Audio-Visual Glossary



D1:  A type of digital video machine made by Sony. It supports High Definition video.

For a technical description of D1, read on… D1 is a format for digital video tape recording working to the CCIR 601, 4:2:2 standard using 19mm wide tape, allowing up to 94 minutes to be recorded on a cassette.


D9:  A type of digital video machine made by JVC. Some of the big video equipment manufacturers have developed their own digital video formats. Sony has their formats (D1, D2, Digital Betacam, etc.). JVC calls their format “D9.” It is just a digital video format with the number 9 to differentiate it from the other brands. Panasonic has their formats - D5 is one of the top digital formats and it will handle all types of video including High Definition. For a technical description of D9, read on…D9, by JVC, specifically is a component digital video format that records onto a ˝ inch cassette and can hold up to 2 hours of programme. D-9 is JVC’s equivalent product to Sony’s Digital Betacam. It uses 4:2:2 sampling, meaning that for every 4 samples of the luminance signal it takes 2 samples of the (B-Y) signal and 2 samples of the (R-Y) - chrominance - signals.


DAC:       Digital to Analogue Converter. See D to A Converter, A To D Converter.


D-A:       Digital to Analogue.


DACRON:      “Dacron” is a trademark for a brand of man-made fibre. It can be woven into a variety of materials including clothing, building insulation, air filters and more. One form of Dacron is a thick cotton-like sheet that is often packaged in large rolls. It can be used as a substitute for fibreglass, which sheds harmful glass particles. Dacron does not shed its fibbers and is therefore safe for the environment and people. It can be used as a sound-absorbing material, and for air filtration.


DAD:      Digital Audio Disc. This is a type of DVD specifically put out with two channel stereo music, uncompressed, at a high digital rate of 24 bit, 96kHz. Small audiophile music companies, such as Chesky and Classic Records, are doing this. This type of DVD is really a DVD-Video disc but it only has music on it and it is to be played in a DVD-Video player. Usually these DAD’s are played by audiophiles who have special digital converter units that are external to the DVD player to get very high quality sound. They are played on a DVD-Video player using either the player’s own two channel analogue left and right outputs, or the player’s digital connection is sent to an external high quality 24 bit, 96kHz digital to analogue converter.


DAIKIN:        A company that specialises in making computer software programming used to author DVD’s.


DAILIES: See RUSHES. It’s the same thing.




DAMPING (AUDIO):     The amount of control an amplifier exerts on a loudspeaker woofer. Underdamping causes loose, heavy bass; overdamping yields very tight but lean bass. The exact right amount of control gives correct bass sounds.



1) A warm, mellow, excessively rich quality in reproduced sound.

2) Often used to describe an unwanted characteristic of a mix or recording where the treble frequencies are weak (too low in volume). Sounds dull, not bright and alive. Opposite of BRIGHT. The sounds are not as present and clear as they are in real life.


DASH:    Abbreviation for Digital Audio Stationary Head. A standard for digital audio tape recording with stationary heads invented by Sony and adopted by Studer and Tascam. What this means is that Sony worked out a way to record digitally on magnetic tape using a tape recorder that looks very similar to a common analogue tape recorder in that it has reels of tape with record and playback heads that are stationary. Another type of method exists using what is called a “rotary head.” If you have ever looked inside a video machine you will have seen a round chrome drum that the tape goes up against to produce the pictures off the video tape. That drum spins round and round very fast to record or read information off a videotape. It is called a “rotary head” because is rotates (turns). Rotary heads are the most common types of heads used for digital audio recording machines. Sony named this system DASH as it uses stationary heads.


DAT:       Digital Audio Tape. The tape used in a DAT Machine. A DAT is a very small tape cassette that is built very much like a normal videocassette tape but it fits in the palm your hand. It can hold a lot of digital information.




DATACAST:   Short for Data Broadcast. The sending of metadata. (See METADATA.)




DATA CD-R (RECORDABLE):       Data CD-R’s are the same as an audio CD-R but are intended to store computer data. Data CD-R’s are used in personal computers to record (“burn”) CD’s. This type of CD is cheaper than audio CD-R’s, which have built-in royalty costs. A personal computer CD burner is much cheaper than a stand-alone unit and reportedly produces better quality discs.


DATA DVD-R (RECORDABLE):     Recordable DVD discs sold on computer gear marketing lines. Note that several types of DVD recorders exist on the market.




DATA PLAY:  This is a very small computer digital storage device, about the size of a quarter. It provides 500 Megabytes of write-once storage and is used in cameras and music players. (See MEMORY STORAGE DEVICES for complete listing.)


DATA RATE vs. DATA STORAGE CAPACITY:       There is a difference between data rate (how fast data is handled) and data storage capacity (how much a data storage medium can hold). One way to sort this out is to take note of the units used in expressing each of these. Data RATES are usually expressed in “number of BITS per second” and data storage capacity is expressed in “number of BYTES.” For example, Megabits per second - also written as Mbps - which means millions of bits per second, is used for data transmission, receiving and processing rates (speed - how much data can be handled per unit of time). Kilobits per second, Megabits per second, etc. are used to designate how much data per unit of time can be transmitted, received and-or processed by computerised equipment. The storage capacity of a given computer hard drive - or medium like a floppy disc - is designated in “bytes” as in Megabytes. (Some floppy discs store 1.4 Megabytes. A CD stores 650 Megabytes and a conventional DVD has a storage capacity of 4.7 Gigabytes.) To help in understanding this, consider that you have a 10 gallon container. The storage capacity of that container is 10 gallons. Now, you could fill your 10 gallon container at a rate of one gallon per second or you could fill it at a rate of one gallon per hour. In any case the time does not affect how many gallons of water the container can hold, it simply affects how fast it is filled. It’s the same with a computer. If your computer can handle data at a rate of 10 Megabits per second, it isn’t going to take too long to fill up a CD. But if it only puts out at a rate of 10 Kilobits per second, it’s going to take quite a while to fill up that CD.

For more technical information on the data rates and storage capacities of CDs and DVD’s, read on… A common CD accepts (records) and plays back at a rate of 1.4 Megabits per second. A conventional DVD records and plays back at approximately 6.1 Megabits per second of audio data and 3.1 Megabits per second of video data for a total of 9.2 Megabits per second. A DVD-Audio is 9.2 Megabits per second (Mbps) - all for audio playback. In other words, the DVD-Video format has its data rate shared by audio and video, whereas the DVD-Audio uses the disc’s 9.2 Mbps rate all for the audio programme. (The storage capacity of a CD is 650 Megabytes and the capacity of a single-layer single-sided DVD-Video or DVD-Audio is 4.7 Gigabytes.)


DATASTREAM, DATA STREAM:        A flow of digital information. Used most commonly when referring to a flow of digital audio or video information. For example, the surround sound channels of audio that are on a DVD disc are actually not stored on the DVD as 6 separate tracks of information, rather, they have been combined down to just one “data-stream”. It is the one data-stream on the DVD that is then split back up into all the separate channels of surround sound when the DVD is played over a surround sound audio system. Another example of a data-stream is on 35mm film prints - the actual film itself shown on a theatre’s projector. Dolby puts a data-stream on the film that is then used to make Dolby Digital Surround Sound in commercial cinema theatres. A data-stream can also be sent between two pieces of digital audiovisual equipment. For example, when making a digital copy of music, the digital information (such as the data from a CD) will travel to the recording machine. That is a data-stream. It is any stream of digital information. Also called a “bit stream.”


DAT MACHINE:    A Digital Audio Tape machine. A type of digital audio tape recorder used in professional studio and film applications. It uses a very small cassette tape that, more or less, looks like a miniature video cassette. The machine actually operates much like a videocassette recorder technically. It is called a “DAT” machine because the type of tape it uses is called “Digital Audio Tape.” Portable DAT machines exist as well. A DAT machine only records two channel stereo. The tapes made on a DAT machine are referred to as “DAT’s.”


DAT MASTER (Digital Audio Tape):     A digital master for every LRH lecture is made for preservation of the tech. The approved mix and edit of each LRH lecture is copied on the Digital PM Line in the Audio Building. These DAT’s are then used to make the metal records that get preserved forever.






dB:  Abbreviation for decibel. (See DECIBEL.)


d&b SPEAKERS:  High quality p.a. speakers manufactured by d&b Audioteknik, a German loudspeaker company, for live events and musical performances.


dBa:       Abbreviation for decibels adjusted. This is a unit of measurement specifically used when the volume of sound in the air is measured (as opposed to the sound signal travelling inside electronic equipment). The measurement is taken in decibels (“dB”). And the “a” means “adjusted” for this reason:     When the same sound is created at different volumes, the individual frequencies which make up that sound are heard differently by the human ear as to their loudness. The dBa measurement unit is used to indicate to professionals in the audio field that these differences were accounted for (adjusted for) when measuring the sound. In other words, someone else reading the measurement will know that the sound’s many frequencies (bass, mids and treble) were measured in such a way that accounted for the fact that different volume levels change how the loudly these frequencies are heard.


dBFS:     An abbreviation for deciBels in relation to Full Scale. The number of decibels below Full Scale Digital. (See DIGITAL LEVELS.)


dBm:      (See ZERO VU.)


dBu:       Abbreviation for decibels unweighted. (WEIGHTING is defined as a separate entry.) This is a unit of measurement of sound volume. The dBu measurement unit is used to indicate to that no “weighting” was used when measuring the sound levels. In other words, there was no adjustment made on the volume measurement equipment to compensate for the ear’s frequency response.


dBV:       means decibels above or below one volt. Unfortunately the audio industry has not agreed upon ONE standard way of measuring signal strength so we encounter different units of measuring the volume of an audio signal. The voltages noted in the parentheses above give a reference in a common unit - the volt.




DBS:       Direct Broadcast Satellite. This term is used to distinguish a satellite broadcast of Digital TV (DTV) or conventional TV where a transmitter on Earth sends a signal directly to a rooftop antenna.


dB STEPS:     “dB” is an abbreviation for decibel, which is a measurement of the volume of sound. The word “steps” as used here means small increases or decreases in amount. “dB steps” is usually preceded by a number. “Set the meter for 2 dB steps.” “That volume control has 1 dB steps.” In the case of the meter, ˝ dB, 1 dB, 2 dB and so on measures the volume of sound. On a volume control knob these steps represent the increases or decreases.




DBX:       Brand name of an audio equipment manufacturer. When one says “DBX” one usually is referring to a specific type of expander they made to reduce noise on a recording. They also made a noise reduction system similar to Dolby’s for the removal of tape hiss. The name probably means:     DB = decibel, a measure of sound volume used in recording. The  “X”  probably means expander  or something  that increases dynamic or volume range of sound.


DC: See Direct Current.


DCA:       Abbreviation for Digitally Controlled Amplifier. An amplifier’s volume is controlled by the digital signal sent to it. This type of amplifier is very small and used inside audiovisual electronics equipment to perform certain internal functions and features.


DCC:       1) See DIGITAL COMPACT CASSETTE. 2) See DIRECTED CHANNEL CHANGE. 3) An abbreviation for Digital Content Creation. Broadly, the use of computers to create images and special effects.


DCM:      A brand of speakers manufactured by the DCM Corporation. DCM means “Distinct Clear Music.”


DCM SURROUNDSCAPE:   The DCM speaker company came up with a novel loudspeaker design specifically for home theatre surround sound. The idea was to build a speaker that would throw the sound around the room so well that the consumer would not have to place any speakers out into the room, as is normally required for film surround sound systems.


DCM TIME WINDOW:        The DCM company produced a loudspeaker that had two sets of speakers in one cabinet, each angled out into the room differently so the sound produced had a large spread and would literally fill up the room. The speaker would seemingly disappear - the music would all seem to travel at different times out into the room. Thus the company named it “Time Window.”


DCS:       Abbreviation for Data Conversion Systems. (Written “dCS.”) The name of a company that manufactures high quality digital converters.




DDD:      A code printed on the packaging of CDs that indicates the CD was produced using a Digital original recording, Digital mixing and editing and Digital mastering and replication. (Compare AAD, ADD.)


DD, DTS:       Stands for DOLBY DIGITAL and DIGITAL THEATRE SYSTEMS. Said of any theatre or audio equipment that has both systems.


DDL:       Digital Delay Line. 1) An electronic mixing component that accepts an audio signal and stores it for a moment, then lets it pass, thus “delaying” it. A digital delay is commonly used in all types of live and studio audio mixing. It creates a single or repeating echo. The echoes (“delays”) can be adjusted to set how long a time period before the delayed sound is heard. It is called a “line” because the signal is routed to the unit - that is the “line” for the signal. 2) Also, at large events and concerts, loudspeakers that are set up at a distance from the stage must have their sound delayed relative to the stage. If the loudspeaker near the listener was not on a delay line, he would hear the sound twice - once from the nearest loudspeaker, and then from the stage because sound travels at a certain speed and the near loudspeaker will be heard while the sound from the stage loudspeakers is still enroute through air to the listener.


DDP, DDP TAPE, DDP ID: This term is used in regards to the production of Compact Discs and is also found in the SADiE digital audio computer manual. Technical terms in this definition are defined as separate entries. “DDP” is an abbreviation for Disc Description Protocol. (A “protocol” is a set of rules and agreements that instruct how computers interact with one another or with other computerised equipment.) “Disc Description Protocol” (DDP) is a data format developed by Doug Carson Associates (DCA). It is the method of assembling the digital information that goes on Compact Discs to prepare the audio information for CD production. DDP is used to create the “Plant Master” - that master (usually an Exabyte tape),  sent to the company that makes the master disc to be used in CD replication. “DDP” refers to all data stored on the Exabyte tape, including the audio programme and the PQ information. (NOTE:   Older methods of preparing CD plant masters, such as using Sony’s 1630 digital video mastering machine or simply making a recordable CD for use as the final plant master, do not utilise DDP processing software - only computers such as SADiE, Sonic Solutions, Audio Cube, and other audio mastering computer systems utilise Disk Description Protocol.) Note:   When only the PQ information on a DDP tape is being referred to (not the audio programme), the PQ code information is sometimes called the “DDP ID” (Disc Description Protocol Identification). The DDP ID is a small computer file that is put on a DDP Exabyte tape. In other words, the part of the DDP tape that contains the PQ data only - not the audio - is the “DDP ID” (also called, generally, the “PQ Code”). The final plant master may also be called a “DDP Tape.”


DDP IMAGE: (See DDP in order to fully understand the following definition.) The computer directory that contains a list of the DDP data. This directory can be displayed on the computer screen, printed out onto a floppy disc, etc. It’s called a “DDP image” because it is the visual representation of the DDP data that can be seen and edited (changed) by those who are using the computer.


DDSC:    An abbreviation for “Dynamic Discrete Surround Circuitry.” This is a marketing name from the Denon Electronics Corporation that is put on some of its audio equipment, such as their AVR 5800 AV Receiver. “Discrete” in this case refers to the electronic circuit parts inside the receiver. Instead of having one computer chip do all of the receiver’s audio functions for surround sound playback, Denon uses discrete (separate and individual) chips and circuits to do this. It’s not a “one chip does all” receiver and is a quality point that Denon markets.


DEAD:    No echo, no reflection of sound whatsoever. A room that has no reflective surfaces off which sound can reflect is called “dead.”




DECAY, DECAY TIME:        The time it takes for echoes and reverberation to die away. The fadeout of a sound after the original sound source has stopped emanating. Like clapping your hands in a large auditorium. You can hear the echoes and reverberation of the hand clap after your put your hands together to make the original sound. That is “decay.”


DECIBEL:      The decibel (dB) is the unit with which sound levels are measured. For example, we read that a jet aircraft as takeoff creates a noise of 130 dB, or that in the countryside on a quiet day the ambient noise level may be about 30 dB.


These and other sounds may be measured with a sound level meter. On the meter, 0 dB corresponds, not to absolute silence, but to the threshold of hearing – that is, the lowest sound pressure level that an average listener with good hearing can detect.


Even a reasonably silent environment will contain a certain amount of background noise, so we may find that in an appar­ently quiet room the sound level is about 30 dB. In other words, the ambient noise level is 30 dB higher than the zero reference level.





             Jet Engine, Close up




             Threshold of Pain


             Pneumatic Hammer

120        Airport Runway


110        Power Tools





             Heavy Truck Traffic


             Average Factory

70         Busy Street

             Small Orchestra

60         Average Conversation


50         Average Office


40         Subdued Conversation


30         Quiet Office


20         Quiet Living Room


10         Quiet Recording Studio


0           Threshold of Hearing


There are actually two measuring systems in which the decibel is used. The first as a measure of acoustic power (as above) and here the decibel tells how loud they are.


The other decibel tells something about electrical power, or in most studio applications, voltage.


DECIMATION:     The word “decimation” as used in digital audio means to eliminate an unwanted part of the signal. It comes from the Latin “decimus” meaning “tenth.” In a certain type of analogue to digital conversion called “over-sampling”, there are additional samples (“over-samples” so to speak) of the audio signal created by an analogue to digital (A to D) converter in order more accurately duplicate the audio signal. Once the over-sampling process is completed, the A to D converter reconstructs the digital audio signal into the machine’s normal sampling rate before it sends the signal out to another piece of digital equipment. When this reconstruction is done, the extra samples created by the A to D converter in its over-sampling process are eliminated (“decimated”) - by filters inside the converter. This filtering process is called “decimation.”


DECK:    A tape machine, whether it be audio or video, analogue or digital. Is short for “Tape Deck.”


DECODE, DECODER:  The prefix “de-” means to reverse the action of. To decode is the process of applying opposite signal processing to restore a signal to its normal state, as in the playback mode of a noise reduction system. For example, a film’s soundtrack is “encoded” into any of the various surround sound formats at the mixing studio and then the consumer’s playback equipment “decodes” it so it can be listened to.


DECRYPT, DECRYPTED:    To make encrypted (scrambled for security reasons) computer information readable.

A studio or production house that specialises in one or just a few different types of work. For example, in the production of a DVD, one can go to get one’s film transferred from film to video at a facility dedicated to doing this type of work very well. There are also facilities called “mastering facilities” or “mastering houses” or “mastering studios.”




DeCSS:  CSS is the copy protection code that is used to prevent unauthorised copying of DVD video content. It is a type of encryption code that is placed right into the video information on the DVD. CSS stands for Content Scrambling System. It messes the pictures up badly if anyone tries to copy them. However, some computer hackers developed a way to defeat an early version of CSS (CSS 1), although the results were a low quality picture. They called the method “DeCSS.” DeCSS could be found on the Internet and downloaded if one searched hard enough. But, it was highly illegal, took nearly a whole day to make a copy of a DVD and the results are a severe quality degrade. The hackers were able to develop DeCSS because one of the companies involved with the development of CSS did not securely encrypt a part of the computer software code they sent around. In response to DeCSS, a newer protection code was developed that supposedly DeCSS can’t crack. The newer protection code for DVD’s is “CSS 2” but the name was entirely changed to Content Protection for Pre-recorded Media (CPPM) so as to have no affiliation with the name of the earlier code (CSS) that had been cracked.


DEEP BASS:  Frequencies below 40 Hz. A bass guitar in a rock band goes down to about 50 Hz, so the “deep bass” is actually lower than that. Deep bass is often created by synthesisers.


DE-ESSER:    A piece of audio mixing equipment specifically designed to minimise or remove sibilance. A De-Esser is often used when the person speaking or singing emphasises “S” sounds or “C” sounds or “Ch” sounds when they say words. 


DEFAULT, DEFAULT POSITION:     The term “default” means to revert to, or be controlled by, a pre-set set of instructions, position or motion. For example, the factory-set default for a computer’s electricity requirements is usually 115 volts, in the USA. In other words, the computer always returns to the 115 volt setting (it “defaults” to that setting), unless otherwise set to accommodate a different voltage by the operator of the computer.


DEFAULT CROSSFADE:      This is a term used in the SADiE digital audio computer manual. “Default is defined directly above this entry. A crossfade is a smooth lessening of the volume of one segment of audio, coincident with a smooth increase of volume of the next segment. When editing in SADiE, a virtual razor blade makes a “cut” in the audio programme. At the exact point of the cut, there is a very brief lessening of the volume (from its full volume down to no sound at all) of one segment of audio. Then, for the next segment of audio, the sound goes from no volume to its full volume. This is so the cuts will go together without a jump. In the case of a SADiE edit, this crossfade is usually very brief in duration, e.g. 1 75th of a second.


DEFINITION or DEFINED:       The quality of a sound or picture that allows it to be distinguished from other sounds or pictures and be heard or seen very clearly and distinctly. 


DEFRAG, DEFRAGMENTATION:      A term used in computers. When a computer stores a file in its internal memory, on a floppy disc or any medium, it puts the files in order, one after another…document 1, document 2, document 3, etc. Each of these documents occupies an exact amount of space in the computer. In using the computer, one often goes back to one or more of the documents and makes changes in them. For example, a change might be done to “document 2” to make it bigger. However, it would now exceed the allocated amount of space the computer had set aside for it when it was originally made. Still the document needs to be saved in the file. To solve this, the computer stores as much of “document 2” as it can in its original storage space. The rest of document 2 (a “fragment”) is stored in the next available file space. When done repeatedly for several documents, this can scatter the files into fragments all over the floppy disc or internal memory of a computer. Then, when one tries to access the file, the computer has to retrieve it from several different places. This is time-consuming. To handle, computers have a “defrag” function that defragments the files and puts them back in order. NOTE: If you wish to activate your computer’s defragmentation programme, ensure you turn off the “screen saver” programme first as this will often interfere with the process. It can take some time for the computer to run this programme - so plan to have the computer do the process overnight.


DEGAUSS, DEGAUSSER:    “Gauss” is a measurement unit of magnetic force. It is named after Karl Friedrich Gauss (1777-1855), a German mathematician and astronomer. 1) Some of the magnetic force used in recording an audio signal onto tape also magnetises the parts of the tape recorder itself. This occurs during both recording and playing back a tape. If enough magnetism is retained by the metal parts of a tape machine, any tape being played or recorded on that machine thereafter will be erased to a greater or lesser degree. After even once playing a tape on a magnetised machine, the programme can become audibly degraded. Usually when a tape is magnetised like this it will have more hissing noise and the recorded audio programme will sound duller. That is why tape recorders and even cassette decks must be demagnetised (“degaussed”) regularly. A “degausser” (also known as a “demagnetiser”) is used for this. 2) Another use for a degausser is to intentionally erase an entire tape so it can be rerecorded or securely disposed of. These types of degaussers are quite large. One puts a full reel of tape onto a conveyor belt and the machine passes the tape through an electrical magnet that erases the tape’s programme. Such a degausser can be seen in a room near the cassette high speed copy line in the cassette manufacturing area.


DEINTERLACING:      This is what a video line-doubler (deinterlacer) does. It takes the odd-lined and even-lined fields of an interlace scanned picture and combines them into one image. Thus it makes an interlaced picture into a progressive picture. (See INTERLACE SCANNING.)




DELAY, DELAYS: 1) The time interval between a direct sound and its echo. This can be generated acoustically from the time it takes for sound to hit a hard surface (such as a wall) and reflect back to the listener, or artificially using an electronic device.


DELAY BOX: See DELAY EFFECT. It’s the same thing.


DELAY EFFECT, DELAY EFFECTS:   1) Any piece of mixing equipment or audio equipment that intentionally creates  a delay. 2) The delayed sound such a unit produces.


DELAY IN THE SURROUNDS:  A mixing term when mixing in surround sound. Sometimes a Mixer will mix a certain sound or sounds into the front speakers in a surround sound mix and then take a “delay” of that sound and put a little in the rear speakers. This can tend to pull the front sound out into the room a bit and make it sound fuller and more “surrounding.” Done both in mixing films and in mixing music for release in surround sound.


DELAYED SURROUNDS:    In most home consumer film surround sound systems the surround loudspeakers are placed out in the listening area. These surround loudspeakers are usually intended to have their sounds slightly delayed compared to the loudspeakers located up front near the screen. Settings for such a delay are normally to be found in the surround sound processor. This is due to the fact that the listener is sitting closer to the surround speakers so their sounds will reach one’s ears sooner than those of the front speakers that carry the dialog, music, etc. To have the surround speakers be heard at the same time as the front speakers, the rear speakers are slightly delayed - meaning an adjustment is done on the surround receiver or processor electronics to make the surround speakers play a fraction of a second later than the front speakers.


DELAY TECH:       (DELAY TECHNOLOGY). This is a mixing technique developed at Gold where a single sound in a mix is made to have a great deal of dimension. This is done by putting the dry (no reverb, no delay added) sound over more towards one speaker (e.g. the left speaker) but then taking that same sound and putting it through several different delays, each with a slightly longer delay time. The sound from each delay is then placed, in the mix, progressively more towards the other stereo speaker. The original dry sound and each delay can then have reverb added. The amount (volume and length of time) of each delay as well as the amount of reverb added to the dry sound as well as the delays, is determined by the Mixer. The added reverb can make the delayed sounds each appear to be positioned further or closer to the listener, depending on the amount of reverb and the reverb settings. The effect created is that the sound appears to come from its first (dry) location BUT space and depth are created. It also sounds much bigger, more open and more natural. The technique was specifically researched and developed based on principles supplied by a famous acoustician, Paul Veneklausen.


DELAY UNIT:       See DELAY EFFECT. It’s the same thing.


DELICATE PRODUCTIONS:      An audiovisual equipment rental company located in Camarillo, California about 1 hour north of Los Angeles that specialises in rentals for live events. Delicate Productions rents audio, lighting and video equipment and they also have resident professionals and crews in each of these fields that can be hired to plan, set up and operate the equipment.


DELTA SIGMA:     An Electronics term used in regards to processing digital audio. This is a key part in analogue to digital converters. (The “analogue to digital converter” is the electronics inside any digital audio equipment that converts the audio to digital information.) “Delta” means “changes” - it is a mathematical symbol that indicates some change of some sort - how much something varied. Sigma means “sum” - the total amount of something. The term “Delta-Sigma” is printed commonly on analogue to digital converters, and is the name of the type of converter used inside. The Delta Sigma converter measures and analyses the incoming audio signal. It combines changes in data (bits) with changes in time (sampling rate) to transform sound into digital information.




DEMO MIX:   A rapidly done mixdown of a song, to get an idea of what the final product will sound like.


DE-NOISE:   This is a term used in the SADiE digital audio computer manual. De-Noise is a computerised feature of the SADiE computer system, developed by the CEDAR company. It is a tool used to remove unwanted noises from a recording. The waveform of the unwanted noise is displayed on the SADiE computer screen along with the desired audio programme. To remove the noise, the Mixer or Editor finds a section of the audio that contains only the noise itself, without any of the wanted programme. This noise will have a definite waveform on the display screen as distinct from the desired sounds. A “sample” of the noise is isolated and the computer can then compare it to the desired sounds being interfered with by the noise. The computer then works to remove the noise, but leave the desired sound for one to hear. 


DENON CD PLAYER:  Brand name of a CD player.


DEPTH:  The perception of relative distance of different sounds from the viewpoint of the listener - an impression of sounds receding behind a loudspeaker, as well as projecting from the speaker into the listening environment. 


DES:      An abbreviation for Digital Encryption Standard. This is a set of regulations from the National Security Agency (NSA) that governs the types of encryption that may be used for any electronic communication that is sent out of the USA. It was developed at Stanford University under the supervision of the NSA. The NSA, a United States government security agency, attempts to maintain the ability to eavesdrop on any electronic communications, even those that are encrypted, for “national security.” The NSA therefore tries to insist that only those encryption methods they have okayed (and can therefore crack) are to be used. However, laws were passed to limit the NSA’s power to stipulate encryption methods and there are now wholly secure methods, that the NSA can’t crack, available for private and commercial use called Public Key Codes. (PUBLIC KEY CODE is defined as a separate entry.) DES is the digital encryption standard that the NSA can monitor. Any type of encryption for text messages or any other form of digital communication being sent outside national boundaries must conform with DES. For example, any encrypted international bank transactions or commercial trade activity (purchases, stocks, interoffice traffic, etc.) done over the Internet must conform with DES in order to be sent over Internet lines.


DESKS:  Another name for mixboards. Principally British slang.




DESCRIPTIVE VIDEO SERVICE (DVS): A television and pre-recorded video service for the sight impaired, similar to closed-captioning for the hearing impaired. (See CLOSED CAPTIONED.) With Descriptive Video Service, a narrator describes the unspoken action and visual cues in a TV show or movie playing on the TV. It is activated by using one’s remote control menu and turning on the  additional audio channel. Such features come with all new TVs and its inclusion on all broadcasts is mandated by the Federal Government in the USA.


DETAIL: 1) The subtlest parts of the original sound, which are usually the first things lost by imperfect components or poor recording, mixing and copying. 2) To “detail a mix” means to do the final polish up to wrap it up.


DETENT:       A notch that you can feel as you move a fader up or down or turn a knob. It signifies the point at which no level boost or cut is being applied by the fader or where its position is to be normally set.


DE-THUMP:  This is a term used in the SADiE digital audio computer manual. Thumps are unwanted low frequency (bass frequency) noises that are sometimes encountered on an audio recording. Such “thumps” are caused by such things as wind noise getting into the microphone when the recording was made, the signer’s hands holding and rubbing the microphone or his breathing into a microphone. The SADiE system can come with a “De-Thumping” computer card that is designed to remove these unwanted low-frequency “thumps.” The De-Thumping feature is designed by the CEDAR company and supplied to SADiE for inclusion in their audio computer system. Unlike ticks, clicks and scratches, which are unwanted sounds that can be removed by other SADiE (CEDAR) processes, these “thumps” often contain actual wanted audio information within their unwanted thump noise. The De-Thumping facility works to remove the “thump” but retain the wanted audio information   that  occurs  during  the  thump  itself. 


DEVELOPING (film developing):   After the film has been exposed it is removed from the camera. The film is taken to a darkroom for development. There, it is treated with chemicals that bring forth the photographed image so that it becomes visible. Once the shot film has been developed it is thereafter called a “negative” and it can be brought out into normal light. The developing process ceases the film’s ability to react to light any further. This “developed” film (the negative) can then be used to make prints.


DFAST:   (See Dynamic Feedback Arrangement Scrambling Technique.)


D5:  A type of digital video machine made by Panasonic. Often used for High Definition film to video transfers.

For a technical description of D5, read on… It is a digital video cassette format that records a digital signal at 10 bit resolution onto a ˝inch tape. The D5 (Panasonic) machines will play a D3 (Sony) recorded videotape. D5 is fully uncompressed component quality video and it will support all forms of High Definition video.


DFT:       Digital Fourier Transform. See FAST FOURIER TRANSFORM.


DGA:      An abbreviation for Director’s Guild of America, the professional organising and negotiating group for directors, assistant directors, production managers, production assistants and stage managers in both the film and television industries. (A “guild” is any organisation or persons with related interests, goals, etc. formed for mutual aid or protection.)


DIAGONAL:  The measurement of any TV’s screen physical size is always taken from two diagonal corners…“The TV’s size is 27 inches diagonal.”


DIALNORM:  (Short for “Dialog Normalisation”.) This is the name of a special feature regarding Digital TV that, when selected by the consumer on his Digital TV receiver or TV, works to keep different stations at the same sound volume. With Dialnorm, the consumer can switch between the different TV stations and they will all have the same apparent loudness.


DIALOGUE:   The spoken word recorded in film or video sound, commercials or other recordings.


DIALOGUE ENHANCER:    On some DVD players, a feature that allows you to hear the dialog, even when the overall volume of one’s audio system is playing quite low (such as late at night so as not to disturb the neighbours). The feature is really included because often consumers do not keep the volume on their TVs very loud when they watch TV and the volume dialog is mixed at for commercial theatre releases is often very low compared to the volume of special effects and big music crescendos.


DIALOGUE NORMALISATION:        On many DVD-Video players and consumer surround sound receivers or processors there is a feature that can work to keep the dialog for a film playing on a surround sound system at a more constant volume. This feature is sometimes used because often the dialog of the film is so low in volume compared to music and sound effects. Usage Note: There is another type of dialog normalisation used in digital t.v. broadcasting called “Dialnorm,” however this is not the same as dialog normalisation for video DVD’s.


DIAMOND STYLUS:    The small diamond tip on a record player that rides in the phonograph’s grooves to create music. (See STYLUS.)


DIAPHRAGM:       In a microphone, the part that moves in response to sound. In a speaker, the part that moves in response to electrical energy being fed to the speaker. The movement of the diaphragm causes pressure changes in the air molecules, resulting in sound.


DIAPHRAGMATIC ABSORBER:        A diaphragm is a surface that is flexible and can bend. In the field of acoustics, sometimes surfaces are installed in rooms that are designed to “bend” when certain sounds strike them. Due to the bending of the surface, the sound is absorbed. It can’t bounce back out into the room as it would after striking a hard reflective surface. Thus the term “diaphragmatic absorber”. It can be as simple as a sheet of thin plywood - anything that can create a surface that will flex when sound hits it. You won’t see the flexing, but the surface is doing so in response to sound hitting it. The amount of stiffness determines what frequencies will be absorbed. Computer programmes are often used to work this out.


DICHROIC:   Descriptive of a type of glass that reflects certain colours while passing others. Such pieces of glass are sometimes used in photography and film projectors to correct or enhance the picture’s look. Comes from Greek meaning “two-coloured.”


DIELECTRIC:       A material that does not conduct electricity. “Di-” means “apart, away or having a reversing force”. A dielectric pushes away or will not pass electricity. In audio, a very common use of dielectric materials is inside wire cables. (Note:  The outside jacket surrounding a cable is not the dielectric.) Cables have more than one wire and if each is not surrounded by a dielectric, the individual signals running in each wire can influence the other wires causing interference or distortion.


DIFFERENT PLANES: When mixing in stereo there is said to be one “plane” - that being the plane (breadth) of sound created between the two stereo loudspeakers. However, when one moves to mixing in surround sound, there are many more planes. The main four planes in surround mixing are the front, rear, left side and right side planes. These planes are created by the front loudspeakers, the rear loudspeakers, the speakers to the left of the listener(s) and the speakers to the right of the listener(s). There are also planes created by the Centre Channel speaker relative to the Left Front and-or the Right Front. Often Mixers mixing in surround sound will establish a reverb setting for each plane of the main four planes. Sometimes even one overall 4 channel reverb will be used for sounds being placed in the four corner loudspeakers, which create the main four main planes, in addition to other reverb units and their settings being used to mix the other planes involved in the overall mix as well.


DIFFUSE:      Sound reproduction in which individual sounds are not present and lack punch and impact. The sounds are severely deficient in detail and they lack exact positioning in terms of location within a mix or as presented by loudspeakers of questionable quality. Sounds that lack body and substance and are sort of diffused in the mix or by the loudspeaker system.  


DIFFUSER:    Any material or surface in a room that does not reflect sound directly back in the direction from which it came, but rather “diffuses” the sound and reflects it back out into the room or auditorium at many different angles. This breaking up of the reflections is very beneficial to the sound in a room as these reflections are minimised and thus don’t muddy up the original sound. If a room or hall is designed specifically for audio purposes, often diffusers are designed and installed to do this function.


DIGIBETA:    Short for Digital Betacam - a professional level Sony video deck and related equipment.   


DIGI-CART:  Short for Digital Cartridge machine. A cart machine is a playback machine that uses tape cartridges instead of open-reel tapes for fast access to a specific sound or a programme. The Digi-Cart, has nearly instant access to any of the sounds it contains.


DIGIDESIGN PROTOOLS: Digidesign is a company that manufactures DAW’s (digital audio workstations). A “workstation” is a computer system that performs all the individual functions required to produce a completed product. The Digidesign Protools is a software package that, when loaded into a computer, will perform multitrack recording, mixing, editing and mastering operations. Many professional studios utilise Digidesign ProTools, including Gold’s Music, A.V. and Cine Mixing studios. The software comes in advancing levels of sound processing capabilities. All audio is recorded and processed within the computer itself. No tape is required and editing can be performed instantaneously. DigiDesign was the first company to design and provide this type of audio computer system.


DIGIDESIGN SUPERCLOCK:    Protools and Avid workstations, made by DigiDesign, use a special form of word clock as a timing reference. This is called “DigiDesign Superclock.” This type of word clock operates at a much faster clock rate than conventional digital audio workstations and non-linear editors. This higher clock speed helps the computers to transmit and receive data more smoothly and to operate faster. If a file from a slower computer is used in an Avid or Protools computer system, the Superclock circuitry speeds up the clock information to match that of the DigiDesign equipment. (See WORD CLOCK for more data on the function of clocks in a computer.)


DIGITAL:      Digital is a term that describes and covers all audio and video recording, mixing, processing, etc. done through the use of computer-based (“digital”) equipment. Digital audiovisual equipment is based on computer principles. Digital equipment uses numbers (digits) to represent sound and pictures. A digital audio recorder records by recognising changes that occur in sound, instant by instant, and it assigns numerical values to each change. These digital values are called “bits.” (A bit is the smallest individual piece of data a computer uses to do work.) The digital audio recorder takes “samples” of the sound as the machine records or plays back. (A sample is a brief instant that the digital device examines the sound and assigns a numerical value to it.) The device takes these samples many thousands of times per second. How many times per second the sampling occurs is called the “sampling rate.” Digital audiovisual equipment can sample at different rates. For example, a CD player samples at 44,100 times per second. Some equipment can sample at 96,000 times per second, or more. Each time a sample of the sound is taken, the machine’s digital electronics convert what it “sees” into a numerical value. It assigns an exact number of bits to each sample. If a machine samples at 44,100 times per second, there are 44,100 individual groups of bits for every second of sound. Professional digital recorders and playbacks usually have a rating of “24 bits,” meaning they have a maximum of 24 bits available to assign to each individual sample. If it is a 16 bit device, such as the CD player, a maximum of 16 bits can be applied toward each sample. As a rule of thumb, the more when the digital audio device plays the programme back, it reads the data off of the disc or other medium and converts it into a sound signal that can be heard over headphones or loudspeakers.




DIGITAL AUDIO SERVER:        A computer-based device that stores huge volumes of audio and can supply it to many separate receiving terminals.



DIGITAL AUDIO TAPE (DAT) MASTER:        A DAT tape that has been recorded to as a final master of a mix or any audio source.


DIGITAL AUDIO WORKSTATION (DAW):    A computer that looks much like a personal computer, but which is specifically for the recording, processing, editing and mixing of audio. The workstation is a full-featured computerised audio processing system. On its screen can be put up a visual representation of the audio, a mix board, tape recorder controls, etc. All the sounds are in the computer digitally. Sounds are recorded into the computer, edited in the computer, mixed in the computer, etc.


DIGITAL BETA MASTER:   A master video tape made on a Sony Digital Betacam. (See DIGITAL BETACAM.)


DIGITAL BETACAM:   Sony brand name for a type of professional video cameras and recorders. Digital Betacam is a Sony format widely used in the audiovisual industry. It records digital component video and 4 tracks of digital audio onto a ˝ inch wide magnetic tape cassette.


DIGITAL BIN:      A digital bin is any computerised storage device. For example, audio cassettes can be duplicated using a digital storage device that holds the master audio programme from which all the cassettes are then copied on high speed copy lines. There is a digital bin used for this on the Gauss Line in the A.V. Manufacturing area.


DIGITAL CABLE READY 1, 2, 3:      Cable TV companies can supply Digital TV broadcasting over their cable networks. “Digital Cable Ready” refers to specific that features High Definition TVs have. “Cable Ready 1” means that the TV can receive both a normal analogue signal and digital Cable TV signal by direct connection to the Cable TV system. It does not need any sort of special wire or connection such as FireWire or a converter box, but it will NOT allow interactive TV. “Cable Ready 2” means that the TV is the same as “1,” but it is possible to connect the TV up for interactive programming using a FireWire cable. “Cable Ready 3” means the same as “1,” but that the TV can receive advanced interactive service programming, and no FireWire connection is needed.




DIGITAL CLONE: A “clone” is a direct digital copy made with no vias between the playback machine and the copy machine except the wire carrying the signal. It is “playback machine to copy machine” using high-grade wiring with each machine perfectly calibrated. The first clone made is considered the “Protection Master” because it “protects” the actual Edit Master from ever having to be used. At Gold, it is the Protection Master that is sent to the Audio Division to receive final mixed audio. The other clones are used for foreign versions and back-up copies.


DIGITAL COMB FILTER:   This is a term commonly used in specifications for home consumer TV’s and projection screen TV’s. In a digital TV or video signal going to a TV set, the “colour” information travels on the same wire that the “brightness” information does. Sometimes, these two signals can interfere with each other and the picture on the screen is not clear and precise. For example, if someone pictured on the TV has a striped shirt, the picture seen can be distorted - the person’s shirt lines are not clearly delineated on the TV screen. They can be fuzzy. The “comb filters” in the TV prevent such distortion and make a far clearer picture.


DIGITAL COMPACT CASSETTE (DCC):  This was a short-lived effort by some companies in  the electronics industry to record digitally to an audio cassette tape. It lasted for about a year in the mid 90s then died with the proliferation and ease of recording one’s own CDs.




DIGITAL CONSOLE:   The basic name of a mixboard that is entirely digital - all controls, and how it routes the sounds of the mix through its internal electronics. The audio comes into the mix board and is converted to a digital signal, if not already digital. The mix board then processes the sound and does all controlling of the sound using digital controls and methods. Even changing volumes of individual sounds is all done digitally. Many companies now make such mix boards, such as Yamaha, Mackie and others. Note that the Euphonix mix boards used here at Gold are not actually Digital Consoles because they are analogue mixboards that are controlled digitally. Often analogue mixboards sound better than all-digital mixboards, though digital controls for the mixboards are highly desirable - and that is what the Euphonix mixboard does (digitally controls analogue mixing processes and signals).


DIGITAL CONTROL:   The controlling of audiovisual equipment digitally. This means that computerised control features are able to cause precise, desired functions of the equipment to be done. For example, Euphonix (brand) mix boards such as the ones in Audio are huge “digital controls” for all the mixing functions that are done. However, in reality, the sounds are actually being mixed inside a tall rack of electronic units located in a separate room near the mixboard. The mixboard that you see, is really just a digital control for all that is done to the sound in the rack of equipment located in the adjacent room.


DIGITAL CONTROLLER:   The new name for an audio preamp that also has full surround sound capability (Dolby, DTS, and other forms of surround sound formats). It is not an Audio Video Receiver (AVR), as AVR’s have amplification for loudspeakers. Also, Digital Controllers differ from “A.V. Processors” in that a controller has many inputs for such equipment as CD players, tape cassette decks, AM, FM tuner, as well as DVD, video inputs, and they have video inputs and outputs for switching video signals between video sources as well (such as between a DVD player and video deck.). A.V. Processors are strictly designed and built to supply surround sound settings and adjustments and they lack any sort of video switching capability and as well have a limited number of inputs and outputs reserved for connection to a separate preamp or digital controller. Note:  Some controllers lack any surround sound processing and adjustments, so are meant to be hooked up to a separate A.V. processor, which is a separate device that has such. A digital controller is usually higher quality than an AVR and it allows the use of a higher quality, separate amplifier, not one built into the same chassis as is the case with an AVR. Sometimes a Digital Controller is called an A.V. Processor and vice versa.


DIGITAL COPY LINE:        The Digital Copy Line in the Gold Audio division was specifically established to provide the very best digital copies of LRH lectures to CST’s archives. Very intensive research and development was done at Gold to establish this line. It is very stringently quality controlled as its products are used to preserve LRH’s lectures for eternity. The final copies, in DAT (Digital Audio Tape) and Ľ inch magnetic tape format, are perfect duplications of the original mix being copied.




DIGITAL DESK:   Another name for a digital mixing console.


DIGITAL DISCS: While this term can be applied to any CD or DVD or other disc storage medium, the term “digital disc” is being used to describe ultra-high quality digital discs that are being sent with full-length feature motion pictures on them to professional theatres to play films digitally. This means no film and no film projector. It is very much the future of general cinema theatre film showings - the use of digital projection using very large and powerful digital projection systems rather than film projectors. Also, such films are being transmitted to some theatres now via satellite - the transmitted film being stored on a huge digital disc.


DIGITAL EDITING:    Film, video and audio editing (assembly of all parts in a desired sequence and timing) done using computerised editing equipment as opposed to cutting actual film or tape and splicing it together or using normal tape machines to copy to other normal tape machines.


DIGITAL EQ, DIGITAL EQUALISATION:      While there are some audio equalisers that are labelled by manufacturers as being “digital eq.,” in fact, they actually process the audio using analogue methods. There is, however, a type of true digital equalisation and other mixing processing devices that do fully process the sound entirely in the digital domain.










DIGITAL INTERCONNECT:      This is the cable, connectors and electronics that allow a CD transport to be hooked up to a D to A converter. Also used to connect an A to D converter to a recorder such as a DAT machine.




DIGITAL MILLENNIUM COPYRIGHT ACT:   (DMCA). A legal set of rules and codes set to protect artists and music corporations due to the growth of copyrighted works being placed on the Internet and broadly used.






DIGITAL MUSIC PLAYER: The same thing as an MP3 player.






DIGITAL RIGHTS MANAGEMENT:      This is a type of copy protection developed and used exclusively by Microsoft for its Windows Media Audio (WMA) Internet music format. Digital Rights Management copy protection is not embedded into the audio content at all. It exists only in the large server computer that supplies music for websites supporting and providing WMA. When a consumer logs onto the website, the Digital Rights Management system simply verifies that he is a paying customer. If so, access to the file is granted and if not it is denied. Digital Rights Management doesn’t prevent any further copying of the material once the consumer has paid for his original copy. 








DIGITAL TELEVISION, DIGITAL TV (DTV):        Digital TV (DTV) is the type of broadcasting that has its programme signal in the form of bits of digital data instead of analogue information. DTV can be received in three basic ways. The first is over the air (broadcasts) via satellite or local stations’ antennas, the second is via a cable DTV service, and the third is via the Internet. To receive DTV requires a special television, antenna and receiver. The type of TV necessary to receive the full quality of digital television broadcasts is a High Definition TV (HDTV). HDTV’s are capable of presenting High Definition video programme sources as well as standard definition digital broadcasts. (Not all DTV programmes are broadcast at the high resolution of High Definition TV.) DTV began in November 1998 when stations in eight US cities began broadcasting using the new Digital TV standards in addition to their normal broadcasts. The plan in the industry is to phase out all analogue broadcasts and have only DTV by 2006.


DIGITAL THEATRES:  Theatres that show movies using digital projectors and a digital playback instead of using film and film projectors. The films are played directly from a high definition video source and projected digitally. Currently, the equipment and procedures necessary to do this are fantastically expensive and is only being used by very few theatres around the world.


DIGITAL THEATRE SYSTEMS (dts):      The surround sound systems developed by Digital Theatre Systems of Westlake Village, California. dts makes a professional surround sound system that is used for general cinema theatres and a number of home surround sound formats as well.


DIGITAL VHS, D-VHS:       Also called “D-VHS” or “D-Video.” This is principally a Panasonic consumer digital video format. JVC is also releasing Digital VHS. It, unlike DVD-Video, can record and play full High Definition video images. The format is not widely in use presently, but promises to be a major format as, unlike DVD, which can only have 480 lines of picture resolution, the D-VHS can have up to 1080 lines for true high definition picture quality. This is highly desired by consumers who have purchased High Definition TVs and High Definition video projectors for their homes. JVC has arranged with major film studios to release films in high definition. Consumers will also be able to record high definition broadcasts right at home using the D-VHS format. It records a digital video at any video resolution desired, with very high quality audio too, onto a normal Super VHS videocassette.


Digital Video:      General term to describe electronic images that are captured, stored and played back using digital computer information and digital computerised equipment and processing techniques.


DIGITAL VIDEO BROADCAST (DVB):   CalledDigital Signal Broadcast” (DSB) in the United States. Any digital broadcast by satellite, by a studio or remote truck. It is called “Digital Video Broadcasting” outside the USA.






DIGITISE:    To “digitise” something means to transform audio and-or video information from an original analogue form into a computer or computerised audiovisual equipment. The analogue information is first converted into digital information and then loaded into the equipment.


DILA:     Abbreviation for Digital Image Light Amplifier. This is a type of digital video projector.


DiMA:     Digital Media Association. Founded in June 1998, the DiMA’s membership is comprised of over 60 major companies involved with all forms and methods of digital media. It focuses much of its efforts on public policy, lobbying before the U.S. Congress, persuading them to modify anti-Internet music and media proposals that would limit Web-based companies from competing with cable and satellite companies as programme distributors. DiMA is also an accredited participant in the United Nations’ World Intellectual Property Organisation (WIPO), which has worked to develop international treaties regarding the use of copyrighted material over the Internet.


DIMENSION, DIMENSIONALITY:  Said to describe a mix or sound heard over loudspeakers where the sound is very open, big, and the individual instruments are clear and each having their own apparent space, location and size. They have dimension.


DIMMER:      A rheostat or similar device by which the intensity of an electric light may be varied. A rheostat is a large variable control for adjusting the amount of current passing through it.


DIN (DIN connector):      Deutsche Industrie Normenausschuss. A German standard for electronic connections and the name of the connectors that meet these standards.


DIODE:  A part used in electronic and electrical circuits to allow current to only flow in one direction. The “di” means “two” and the “ode” means “electrodes.” Therefore it has “two electrodes.”


DIPOLE:        See MONOPOLE for full definition. Compare BIPOLE.




DIP SWITCH:      A switch often mounted on a printed circuit board that commonly has from 2 to 8 or more switches within a single package, that turns on or off various functions in a piece of equipment. These switches are very compact and usually have to be switched using a small screwdriver (tweaker) or some such tool.


DIRECT BOX OR “DI” BOX:     DI is an abbreviation for Direct Input. This is a small and very portable unit that can be plugged into a line between a musical instrument and a mixing console that allows the instrument to be plugged in directly, as opposed to using a microphone. Sometimes the output of electronic musical instruments, including guitars and bass guitars, is not strong enough to run down a long length of wire to the mix board. A DI box will help with this problem. It is a box that allows the instrument to be plugged in “direct” to the mix board, rather than having to go via the instrument’s usual amplifier (such as a guitar amp). Some amplifiers also have an output so that their signal can be sent direct to the mix board, before it goes to the internal speakers of the amplifier itself. This is called a “direct out.”


DIRECTED CHANNEL CHANGE (DCC):  This is a feature for Digital TV stipulated by the Advanced Television Systems Committee (ATSC). With Directed Channel Change, broadcasters can tailor programming or advertising based upon viewer-supplied demographic information and essentially “change the channel” for the viewer. The broadcasting station can transmit multiple programmes and-or programme versions simultaneously using different channels and the viewer’s set-top receiver for Digital TV will automatically switch to the specific programme or commercial based upon the information voluntarily entered by the consumer, such as the viewer’s zip code. When a consumer sets up his television using his remote control, he or she may be prompted to enter in their zip code or other information. The television will then display a programme that is more tailored to the home consumer. Note that the directed channel change function doesn’t give an unlimited choice at all. It is not the same thing as Video On Demand. It does enable the average viewer to programme his television to receive the programming that is more suited to what he or she generally wants to watch or for programmes and commercials that are applicable to his location. For example, this means that a local commercial can air specifically for that public viewer, or the name of the nearest local Scientology org and information about it be provided to that select area of viewers - all done automatically by the home consumer’s television receiver. The channel is actually “changed” by the viewer’s set-top receiver, which receives a code signal sent from the broadcaster. The receiver then changes it to a specific channel that has the programme or commercial version appropriate to that viewer based on the information he or she has voluntarily loaded into the receiver.


DIRECT CURRENT:    See Alternating current.


DIRECTOR’S CUT:      At times, when a movie is put out on DVD, it is re-edited in the way that the Director prefers and preferred. Sometimes a film is edited down in length or some scenes taken out when released on film to general cinema theatres. This might be due to surveys of public, or ordered by movie studio executives for one reason or another. The Directors “cut” is how he always wanted to have the film edited (cut).





1) This is a feature on many mixing consoles that allows connection directly to the output of an individual channel in the console before it goes through all the other wires and circuitry.

2) Some amplifiers also have an output so that their signal can be sent direct to the mixboard, before it goes to the internal speakers of the amplifier itself. This is called a “direct out.”


DIRECT SOUND: A sound reaching the ears in a straight line from its source. The direct sounds are always the first sounds heard. The direct sound is not the sound heard reflecting off of any surface. It is the sound heard directly from a loudspeaker or other source of sound, not influenced by any reflections.


DIRECT TV, DirecTV: (Correctly written “DirecTV.”) A DSS (Digital Satellite System) TV company.


DIRECT-VIEW SETS: This is a more recent term for normal TVs. They are called “direct view” because one looks directly at the source of the picture (the picture tube) Other types of sets exist - such as large “projection TVs”, which have a screen but the source of the picture is deep inside its box and the picture reflects off a mirror onto the screen. Therefore, one is not seeing the “direct” source of the pictures but rather a reflected one.


DIRECT X:    A format of computer plug-in software that is designed to be used with smaller digital audio workstations (DAW’s), such as those based on Windows 98 and Windows NT. Direct X is not fully supported by the larger computerised digital audio workstations like Protools and SADiE. It can be used with SADiE, but not to its full capacity. (When used in a Windows platform, Direct X can transfer files at faster than real time speed, but it cannot be used with SADiE’s faster than real time processes.) Equipment manuals for DAWs usually state which formats their system will support. If not clearly stated in the manual, the manufacturer should be consulted.



1) A sound that is not “clean.” The sound lacks clarity and, due to a very small amount of distortion (a fuzziness or graininess), one cannot hear all the small details that make the sound appear to be natural and have complete reality.

2) A mix or loudspeaker system can have a “dirty” quality. One cannot hear the sounds well because the images (sounds) do not have great clarity and delineation between each other.

3) Roughness or gritty quality in the sound.

4) It’s a tiny bit of distortion, a bit of fuzziness to the sound or picture. Loudspeaker systems can sound dirty when they are of poor quality.

5) Sometimes a sound is intentionally made dirty, such as a “dirty sounding electric guitar,” or a rock singer’s voice can intentionally be a bit dirty. This type of dirty can be a plus, when desired.


DIRTY DUP(licate):   A black and white copy of the work print that is used in editing to prevent excessive handling (and potentially damaging) of a film’s work print.


DIRTY POWER:   Refers to power that has inconsistent voltage or has distortions in it. Dirty power is what comes out of normal electrical wall outlets. Ideally, these are not used for computers and A.V. equipment. (Compare CLEAN POWER.)


DISC-AT-ONCE CD:    This is a term found in the SADiE digital audio computer manual. When all the songs (or tracks) for a new CD have been fully mixed and one is now ready to make a CD, the SADiE computer has the ability to make a CD. All the audio for the CD can be recorded at one time to a recordable CD using the SADiE system. The entire CD can be recorded - the SADiE will take all the tracks and record them, one after another, following exact instructions stipulated by the SADiE operator. This is as opposed to recording one song only to the CD, then recording the next song at a later date, then another still later on, etc. Instead, all the final mixes can be stored in the SADiE system and when one is ready to make a CD, the “Disc-At-Once CD” feature is used so the entire CD is recorded. SADiE does this real-time, meaning each song plays through fully, just as it was mixed, and then the next song is automatically recorded. (It can also record faster than real-time.) The process repeats until all songs are transferred to the recordable CD. It is therefore possible to produce the entire disc at one time - thus, “Disc-At-Once CD”, is the name of the SADiE feature. The “Disc-At-Once CD” feature is recommended by SADiE as the preferred method of creating a final CD recording of the completed songs for the album. (Compare to TRACK-AT-ONCE CD.)




DISC DRIVE:       The mechanism in a computer that writes onto and reads from a floppy disc. This is not a CD Drive.


DISC EXPLORER:       A feature on some DVD or CD changers that hold many different discs (called MEGACHANGERS). The Explorer function allows one to find desired discs.


DISCRETE INPUTS:   1) Five, six or more inputs labelled “discrete inputs” may be found on higher quality surround sound receivers, processors and preamplifiers. DVD-Video players are actually hooked up to surround sound receivers and processors with only one digital wire, if Dolby or DTS digital film surround sound is to be played. If the player is to play a CD (which all DVD players can do), that audio is sent to the receiver using two analogue inputs. A DVD-Audio disc on the other hand, or one of Sony’s SACD discs in surround sound, are meant to be hooked up to 5 or 6 discrete (separate) inputs on the receiver, processor or pre-amp - if the consumer model to be used has such. Otherwise, it can only play surround using Dolby or DTS. 2) Any entirely separate input(s) on any audio or video equipment, professional or consumer level, that keeps the signal separate at all times.


DISCRETE SOURCES: Individual, totally separately recorded sounds, each having their own track on a tape recorder. They were not in any way mixed with any other sound when recorded so therefore are able to be assigned to their own individual mixboard channels and mixed and processed entirely individually.


DISCRETE SURROUND SOUND:     The word “discrete,” in audio, means completely individual and not depending upon anything else. Discrete surround is the surround sound format where each channel of the surround audio is kept entirely separate, recorded separately and played back each over their own individual loudspeaker with no type of processing or combining at any stage. DVD-Audio disc playback is designed to be done using 5 or 6 discrete channels, not processed by any film surround sound method such as Dolby or DTS. This is possible if the discrete outputs of the DVD-Audio player can be routed to discrete inputs on a surround sound processor or preamplifier or receiver in a surround sound audio system. Sony’s SACD discs are meant to be played as discrete surround sound. These players can also provide other formats of the music, such as a stereo version. (See SMART FOLD-DOWN for how a DVD-Audio disc does this.) The Sony SACD’s have two layers of audio on the actual CDs themselves - one layer has surround sound, and the other a stereo version of the same piece of music. The stereo version will play in a CD player. The surround version requires an SACD player.


DISCRETE MOSFET DEVICES: A type of transistor used in audio amplifiers. MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor.    


DISHED OR DISHED-DOWN:   1) Describes a frequency response that is depressed through the entire middle range. The sound has too much bass and treble compared to midrange frequencies. 2) The term is also used to describe how sound is heard over a loudspeaker system wherein the music seems excessively withdrawn or distant from the listener. It is called “dished” because it’s as though the lacking frequencies or presence are “dished” (like in the shape of dish).


DISH NETWORK:        This is another provider of satellite TV programming. They are part of a larger company called EchoStar Communications. “DISH” is an acronym for Digital Sky Highway, a term made up by Dish Network symbolising satellite TV broadcasting.


DISH PLAYER:     A brand name digital satellite receiver and recorder, playback device manufactured by a digital satellite company called EchoStar. It is for home consumer use. The “Dish” in Dish Player (and in Dish Network) is an acronym for Digital Sky Highway. It is a consumer unit that receives and can record digital broadcasts. It utilises a computer hard drive to record up to 3 hours of programme.


DISKETTE:    See FLOPPY DISC. It’s the same thing.


DISPLAY, DISPLAY SCREEN:  Said of some TV type screens. The word “display” is used to distinguish types of screens that are not like a normal TV screen that uses a picture tube. A “display” is like one of the flat type screens one sees commonly used with computers.


DISSONANT:       Unpleasant to the ear; not enjoyable sounding. Dissonance is where various sounds do not seem to go well together, like their various qualities and timbre do not seem to compliment each other but instead are irritating. (See CONSONANT for comparison and for derivation.)


DISTRESSOR:      The name of a computer plug-in software made by Empirical Labs. The “Distressor” is a combination distortion effects and compressor card that can be plugged into a digital audio workstation and used for music mixing. The Distressor is designed to replicate the sound of vintage compressors and guitar distortion pedals




DITHER:        Dither is a very quiet hissing type noise sometimes added to audio as it is being recorded digitally. This is done by electronic circuits within the digital recorder itself, and is used to help the digital recorder to A-B better and to reproduce sound that is more lifelike. Usage Note:    To understand dither and how it is used, realise that sounds in real life have many qualities that make them sound real. Some of these qualities are so subtle that one does not really notice them, unless they were suddenly absent. For example, the very soft way a musician blows his flute might create a subtle quality that markedly contributes to the unique character of its sound. The flute may sound quite usual to you, given a casual listen. But, if listened to closely, these nuances will very much be there, each contributing to the flute’s characteristic sound. These qualities are sometimes “too fine” (too slight; too low in volume) for digital equipment to fully record or play. The fact is that a very subtle sound may be too “small” to be accurately recorded and played back by the digital machine. It can be too low in volume for the digital machine to recognise it. Therefore, to sort of “trick” the digital recorder to better record such nuances, dither is used. Dither adds a very quiet hissing or other type of noise into the sound as the recording is made. If done properly, dither isn’t noticed by those listening to the final recording. The word “dither” comes from Middle English meaning a “state of agitation.” Because the dither noise is slightly there, it literally keeps “agitating” the data bit that records and plays back the lowest volume sounds - where the subtle details are. It keeps this bit recording (or playing back) and thus active. The dither noise keeps this bit recording, even though it isn’t detecting the actual lowest volume subtleties. In other words, even though it is not actually detecting the subtleties of the sound, the bit keeps recording the dither. The result is an appearance that more of the subtle details of the sound were recorded. Additionally, dither helps to reduce distortion. It does this in the following way:      Though the digital recording process may not quite capture all the given subtleties, it often records them to a greater or lesser degree. In other words, it may only record a half or part of the whole sound available. If you were to visually represent this incompletely recorded sound on an oscilloscope, the partial digital recording of the very subtle sounds would have missing parts and look jagged. The waveform would not be complete. A sound with missing or jagged parts is heard as having less resolution than the original and in extreme cases as distortion. Dither fills in these jagged parts, and smoothes out the sound.


DIVERGENCE:     This is a term used in the SADiE digital audio computer manual. In mixing a surround sound audio programme, the various sounds are placed by the Mixer so they appear to come from a position in space that is appropriate to the soundtrack. For example, the dialog is usually routed to the centre loudspeaker so it appears to come from the actors’ mouths when they are seen on the screen and music and sound effects are often put in loudspeakers to the left and right of the screen. If there is a gunshot to the left as seen on the screen, then the Mixer can have the sound of the gun more in the left loudspeaker. With the SADiE system, it is possible to do full surround sound mixes. The way the SADiE starts off a surround sound mix is that it actually assigns all the sounds to the middle (centre channel). From there, the Mixer using the SADiE system can decide which sounds he wants to move out to another loudspeaker or loudspeakers, and to which loudspeakers precisely. It is the “Divergence” control that the Mixer uses to do this - allows the Mixer to “divert” sounds to other loudspeakers. It’s a feature and method of mixing for surround sound developed by SADiE. As a sound is panned toward the centre loudspeaker, the Divergence control will balance how much audio comes out of the centre speaker in relationship to the left and right.


Di Vi Awards:      Digital Video Awards. See DVD ENTERTAINMENT GROUP.


DivX:      A new video copying technology for copying and transmitting pictures over the Internet. It was developed by a team of hackers and it works much the same way MP3 works for music to be copied and transmitted. It uses MP4 video technology. (See MP4, MP3.)


DLC:       Abbreviation for Diamond-Like Carbon. A coating put on Sony AME (Advanced Metal Evaporated) brand tape.


DLP:       Abbreviation for Digital Lens Projector.


DLT:       Abbreviation for Digital Linear Tape. This is a format of digital audio tape that is used for mastering and archiving. It is packaged in a cartridge and looks similar to a small video cassette.


DMCA:    (See Digital Millennium Copyright Act.)


DME:      An abbreviation for Dialog, Music, sound Effects, the three basic constituent parts of film soundtracks. This term is also used in Digital TV broadcasting, especially where multilingual soundtracks are concerned. The M&E soundtracks are broadcast separately from the dialog tracks of any of various languages. Receiving this type of broadcast requires a dual stream receiver, meaning one that is capable of receiving and processing two separate audio data streams. (See DUAL STREAM AUDIO DECODER.)




DOCSIS:        Acronym for Data Over Cable Standard Interface Specification. This is a term in regards to Digital TV (DTV) when received over cable from Cable DTV providers. It is the specification for high-speed cable modems. Cable modems are used to send digital TV programmes along with additional data such as interactive programming. In Europe, it is called EURO DOCSIS. The DOCSIS specifications were established by the “Cable Labs.” (CABLE LABS is defined as a separate entry.)


DOCUMENTATION, DOCUMENTATION BINDERS:     When an audiovisual production line is established, all aspects regarding the line and all procedures used to get a product and to QC that product are documented in writing. This information, very clear and easy to read, is contained in DOCUMENTATION BINDERS for the line. The word comes from the Latin ‘Documentum’, example, proof, which comes from ‘Docere’, to show, teach.


DOME TWEETER:        A type of tweeter(speaker) that specifically and only reproduces the high (treble) frequencies of audio programmes. A dome tweeter has a dome shape. It is usually made of black stiff silk or a very thin metal. The dome shape allows the frequencies to radiate out evenly in a large area. Other tweeter designs may handle more power (wattage), but lack the wide dispersion characteristic of the dome design.


DOLBY:  An audio electronics company. “Dolby” is a man’s name - one of the most famous in the audio and film fields. His name is Raymond Dolby. All analogue recording tape, when played, makes a very slight (but audible) “hissing” sound, even when the tape is blank. Dolby created a “noise reduction system” (an electronic circuit) for tape recorders of all types that reduces this hiss. As a result, tape recordings were much clearer sounding. Dolby also developed many other audio systems such as a type of surround sound for films and videos. The various types of Dolby systems are each listed below.


DOLBY A:      A noise reduction system for use in professional studios making analogue recordings on magnetic tape. The Dolby A system gets rid of the “hissing” sound that tape inherently has when played, even when no recording is on the tape. This hiss, if not removed, is very audible. With Dolby A, it is virtually inaudible and high quality sound from the tape is made possible. Dolby A is still in use around the world, but Dolby came out with an improved noise reduction system called “Dolby SR,” which is what we use for analogue recordings. (See DOLBY SR.)

For a more technical description of Dolby A, read on… Dolby A separates the audio programme into four different frequency bands. Each of these bands is separately compressed at attack and release times that are appropriate for the frequency band (faster at high frequencies, slower at low frequencies). The four bands are then re-combined to record onto tape. For playback the process is reversed and the expanders (used to undo the compression) and in doing this push the tape noise down to a much lower volume.


DOLBY AAC: Dolby Advanced Audio Coding. (See ADVANCED AUDIO CODING for full definition of this compression format for audio and video information on the Internet and other uses.)


DOLBY AC-3 (or AC-3, DOLBY DIGITAL, DOLBY DIGITAL SURROUND):   This is Dolby’s digital surround sound format for both professional theatre and for use in home surround sound systems. It is also the type of Dolby used for the broadcast of Digital TV with surround sound audio in a version called “Dolby E.” With many TV shows having surround sound mixes when broadcast over Digital TV, plus the fact that most films have Dolby Digital Surround, this is a well-known surround sound format. The term AC-3 was simply a technical “in-house” Dolby term that was not to have ever gotten out to the consumers, but the press got hold of it. Dolby’s public release name for this format is “DOLBY DIGITAL” or “DOLBY DIGITAL SURROUND.” There are newer versions of Dolby Digital Surround - called “Surround Extended (EX) which add additional channels of surround sound to the rear wall behind a listener. There are many different types of Dolby Digital Surround Sound and these can be found below as separate entries in this glossary or entirely listed in sequence under SURROUND SOUND FORMATS AND TYPES. (See DVD PLAYER for how to hook up for Dolby Digital surround sound.)

For more information on Dolby Digital AC-3, read on… AC-3 is the Dolby Digital Surround Sound format. All Dolby’s digital surround sound formats, be they for professional use, or for home consumer use, are based on AC-3. The term AC-3 is used frequently throughout home theatre magazines and on much home consumer equipment, so it is important to know what it means. AC-3 stands for Audio Codec-3. “Codec” stands for “compression” and “decompression” - it is a general word for digital compression (the squeezing of digital information so more can be stored in less space, such as on a CD or DVD). Dolby Digital surround sound (AC-3), no matter what type, is a compressed digital format - about 12 to 1 compression is applied. Note that the DVD-Video disc is too small to store multi-channel surround information for a film and therefore the compression is required. Even DTS does the same for its system, but at less compression (about 4 to 1). Both DTS and Dolby use “perceptual coding” to perform the compression process. (See COMPRESSION3 and PERCEPTUAL CODING.) The “3” in the name AC-3 simply indicates the “3rd version” of the process. All versions of the Dolby Digital system are generally 16 bit, 48kHz sampling rate. It is a lossy codec. The DTS surround system, on the other hand, is 20 bit, and adheres to the industry technical standards for CD’s so, while it is also a lossy codec, it is less severe.


DOLBY B:      A noise reduction system for cassette tape recording and playback. Most pre-recorded cassettes are Dolby B. This is the principal Dolby tape cassette noise reduction electronics that virtually all cassette tape duplicators use. All cassette decks, including most car cassette players, have Dolby B. It gets rid of the “hissing” sound that cassette tape inherently has. This hiss, if not removed, is very audible. With Dolby B, it is very much reduced, and high quality sound from the cassette tape format is made possible.

For a technical description of Dolby B, read on… The signal is compressed during recording and expanded during playback. The control circuits of the compressor and expander are sensitive to high frequencies only.


DOLBY C:      A noise reduction system for audio cassette tape recording that was developed subsequent to the Dolby B system. It came out from Dolby just as the CD was catching on in popularity so Dolby C, while it is on most all cassette decks, never really was used widely by the audio industry to produce cassettes. In addition to reducing tape hiss, Dolby C limits the volume of loud high frequency sounds during the recording process to minimise distortion.


DOLBY CHIP:       Dolby Laboratories has patented many different noise reduction and sound recording or playback systems. A “chip” is another word for “Integrated circuit.” A “Dolby Chip” is an integrated circuit that has been programmed to play back soundtracks that were recorded using a Dolby system. These chips can be installed into a piece of equipment enabling it to play back Dolby recordings. Or, Dolby’s chip design can be integrated into other manufacturers’ chips so they also contain the Dolby processing. There are Dolby surround sound chips and noise reduction chips.


DOLBY CP65:       The CP65 is a Dolby surround sound unit used in theatres to create Dolby Surround Sound (non-digital). Its forerunner was the Dolby CP 55 unit. It performs the electronic decoding and equalisation to produce surround sound in movie theatres.








DOLBY DIGITAL 5.1: This is the original Dolby Digital Surround Sound as released in the early 90’s for theatres and home theatres. It consists of 5 channels of audio plus an additional channel for the very low bass information (the “.1”). (See DOLBY DIGITAL SURROUND SOUND.)


DOLBY DIGITAL MATRIX EX (6.1):       This is a type of Dolby Digital surround sound, specifically designed to be able to play all film videos that have been mixed with the original Dolby Digital 5.1 surround sound and play them back as Dolby Digital EX 6.1 Surround Extended. This Dolby system creates an additional channel of rear wall surround giving one additional surround channel to the original 5.1 version.








DOLBY DM 100:  A, very small hand-held unit from Dolby that allows one to decode and test the quality of Dolby E and other Dolby bit-streams. (See DOLBY E.)


DOLBY DP 562:   Dolby Digital Processor #562. The numbers “562” are simply Dolby’s own catalogue numbering system. This is the decoding unit used by digital TV broadcasters that goes along with the Dolby DP 569. (See DOLBY DP 569 below.) The DP 562 unit is used at the broadcast station to monitor the audio signal of a Dolby Digital broadcast before it is sent to the home consumer.


DOLBY DP 569:   Dolby Digital Processor #569. The numbers “569” are simply Dolby’s own catalogue numbering system. The DP 569 is the Dolby unit used by Digital TV broadcasters to encode a soundtrack that is to be broadcast in Dolby Digital Surround Sound. Version 2.0 of the DP 569 was released in April, 2001. Note that the 569 unit is used by broadcasters. The studio producing the soundtrack uses the Dolby E DP 571 encoder to create the audio for Digital TV broadcast. This Dolby E soundtrack is turned over to the broadcaster who plays it back through a Dolby E DP 572 decoder. Next, the soundtrack must be put into a form, which can be received by home consumers. To do this, the broadcaster takes the decoded Dolby E data stream and plays it through a Dolby DP 569 encoder that turns the Dolby E stream into Dolby Digital Surround Sound for the broadcast. This encoded Dolby Digital stream is then received by the home consumer’s receiving equipment and decoded into 5.1 surround sound. (The broadcast station uses a Dolby DP 562 decoding unit to monitor the audio after it has been encoded using the DP 569 for broadcast to home consumers.) Note: There is a distinction made between Dolby E and Dolby Digital. Dolby E specifically refers to the data stream created by the studio producing an A.V. product for broadcast. The Dolby E stream is then decoded (with the DP 572) by the broadcaster and then re-encoded (with the DP 569). At this point, the soundtrack becomes a Dolby Digital data stream which can be received by the home consumer. The distinction is made to differentiate the production of the audio done by the studio from the broadcast and receiving of Dolby Digital Surround Sound. It is also important to note that not all television service providers (including satellite, terrestrial, internet and cable) have Dolby Digital capability. Before committing to a broadcast, it is vital to ensure the broadcaster has the facility to accept the audio format you are providing.


DOLBY DP 570:   Dolby Digital Processor # 570. (Note:      The digits “570” are of no significance other than to designate this specific Dolby model). The Dolby DP 570 is used in conjunction with Dolby E for digital audio broadcasting. (See DOLBY E.) The DP 570 is not an encoder nor is it a decoder. It is an authoring tool intended solely for professional use - not a home consumer unit. (See AUTHORING.) The DP 570 is used in conjunction with the Dolby E DP 571 encoder to add metadata into the Dolby Digital soundtrack for an A.V. product (be it pre-recorded or live) in preparing it for television broadcast. (See METADATA.) The 570 can also be used with the Dolby DP 569 digital surround sound broadcast system. Dolby DP 570 metadata is programmed by the audio Mixing Engineer or whoever is authoring the soundtrack to give instructions to the home consumer’s digital AVR (Audio Video Receiver) as to exactly how it should reproduce the soundtrack - i.e. Dolby Digital EX 7.1, Dolby Digital EX 6.1, Dolby Digital 5.1, etc.

Important technical note for those involved in producing a Dolby Digital broadcast… The Dolby DP 570 Authoring Tool does NOT add any latency to the audio signal. In other words it doesn’t delay the signal so does not require any compensation for keeping it in synch. It doesn’t encode, decode or compress the audio data so does not delay the signal at all.


DOLBY DP 571:   Dolby Digital Processor #571. (Note: The digits “571” are of no significance other than to designate this specific Dolby model). This is the professional encoding unit required to produce Dolby E for surround mixes that are broadcast over Digital TV. This unit is used by the studio producing the soundtrack to create the Dolby E data stream. It is used in conjunction with a Dolby DP 570 and DP 572 - and a DP 569 which is used by the Digital TV broadcaster.


DOLBY DP 572:   Dolby Digital Processor #572. (Note: The digits “572” are of no significance other than to designate this specific Dolby model). This is the professional decoding unit required to produce Dolby E for surround mixes that are broadcast over Digital TV. Used in conjunction with a Dolby DP 571 and DP 570 - and a DP 569 which is used by the Digital TV broadcaster.


DOLBY DP 579:   Dolby Digital Processor #579. (Note: The digits “579” are of no significance other than to designate this specific Dolby model). This is a Dolby unit used by professional audio and video facilities to synchronise a Dolby E digital data stream with pictures when doing a telecine in the High Definition format. This includes High Definition 24 fps progressive scanning. For example, if a movie had been shot on film and was then transferred onto High Definition video at 24 fps to create a 24 fps progressive scan High Def video, the DP 579 would synchronise the Dolby E audio with the telecine machine.


DOLBY DP 583:   (See the glossary entry RECLOCKING to understand what the DP 583 is used for.) Dolby Digital Processor # 583. (Note:    The digits “583” are of no significance other than to designate this specific Dolby model). This is a professional unit for use by mixing studios and broadcasters to reclock the Dolby Digital data stream. This ensures that the playback done of the Dolby Digital soundtrack will be accurate. For example, a Dolby E broadcast mix done at a studio which is then taken to a broadcast station in another part of the city or country. To ensure the best possible accuracy of playback, the Dolby E soundtrack is played back through the DP 583 which reclocks the data stream so that it plays back perfectly through the equipment in the broadcast station.


DOLBY E:      Dolby E is an audio format for digital television broadcast applications. The version of Dolby AC-3 used by professional studios to create soundtracks for Digital TV is called “DOLBY E.” While normal Dolby Digital AC-3 surround sound encodes the entire 6 channel discrete mix down to one data-stream that is put on a DVD-Video disc, DOLBY E encodes the surround mix in a special way for Digital TV - it creates a data-stream that is broadcast with the TV or Video pictures. DOLBY E also allows many different versions of the audio to be played by the consumer as well. (For information on preparing surround sound mixes for television airing, see DOLBY DP 569, DOLBY DP 570.) DOLBY E has 8 channels that can be sent on one AES digital audio wire pair or on two audio tracks of digital video tape or a video server. It is a way to get surround sound into a home on a Digital TV broadcast. Dolby E is for professional use only. What it does is allow a 2 channel audio studio to produce a Dolby Digital Surround (5.1 channel) mix for Digital TV airings. The mix is done through the Dolby E DP 571 encoder and 572 decoder. A Dolby 570 unit is also used. These boxes are used in the preparation of soundtracks for television broadcasts that have Dolby Digital Surround Sound. The 571 unit is the Dolby E encoder used to compress the audio signal of a programme for television broadcast so that it will fit within the amount of digital processing power of the Digital Television format. At the studio, the signal is also decoded by another Dolby E unit, called the DP 572. This decoding box is used to listen to the surround mix just like the public viewing audience will hear it. The 572 decodes the TV surround sound so the mix can be heard and QC’ed before it is sent to air. The signal is then re-encoded by the broadcaster using a Dolby DP 569 encoder to create a Dolby Digital Surround Sound 5.1 data stream which can be broadcast and then received by home consumers. Upon receipt of the Digital TV broadcast, the home consumer’s A.V. receiver decodes the Dolby Digital information so that the soundtrack can be heard as 5.1 surround sound. The consumer simply plays the programming via the Dolby Digital Surround Sound setting on his home theatre audio equipment.

Important technical note for those involved in producing a Dolby Digital broadcast… The 571-572 system is a dual system. When broadcasting digital audio along with video, there are often timing differences between the sound and pictures that can show up as loss of lip synch. This is due to the “latency” inherent in the digital audio-video process. The DP 571-572 system adds approximately 30 milliseconds of delay to the audio programme. When preparing a programme for broadcast, the audio and video engineers take this and any other latency into account so that the resulting broadcast is in perfect synch. Note: There is a distinction made between Dolby E and Dolby Digital. Dolby E specifically refers to the data stream created by the studio producing an A.V. product for broadcast. The Dolby E stream is then decoded (with the DP 572) by the broadcaster and then re-encoded (with the DP 569). At this point, the soundtrack becomes a Dolby Digital data stream which can be received by the home consumer. The distinction is made to differentiate the production of the audio done by the studio from the broadcast and receiving of Dolby Digital Surround Sound. It is also important to note that not all television service providers (satellite, terrestrial and cable) have Dolby Digital capability. Before committing to a broadcast, it is vital to ensure the broadcaster has the facility to accept the audio format you are providing.


DOLBY ENCODE, DECODE:      These terms are used regarding the Dolby systems that are used to reduce tape noise, such as Dolby SR for professional audio and Dolby B for cassettes. Analogue audio tape has an audible amount of noise (a hissing sound) inherent in the medium. Dolby noise reduction is used to remove the hiss so it is doesn’t detract from the clarity of the sound. When using these systems, there is a dual process. The first is used during recording and the second is for playback. During recording the audio signal is sent through a Dolby encode unit and during playback, a Dolby decode unit. Technical descriptions of exactly how these units work are fully written up in Dolby manuals, but basically they work together and result in greatly reduced tape hiss.


DOLBY EX (Surround Extended 6.1 and 7.1):    Stands for Dolby Digital Surround Extended. Dolby EX is a 6 or 7 channel digital surround format with one subwoofer output. It differs from normal Dolby Digital Surround in that it adds a rear-wall channel of surround, called a “Back Surround.” Dolby also has a version that creates two independent back surround channels. Dolby EX is for both commercial cinema theatres that pass THX certifications as well as for home consumers.








DOLBY HX PRO:  This is a professional level Dolby distortion reduction system that also increases sound quality. It is sometimes used professionally on cassette high speed copy lines. The HX Pro system applies a special Dolby process that reduces distortion and provides greater clarity of the high frequencies of the recorded programme.

For a technical description, read on…HX Pro stands for Headroom eXtension PROfessional. This is a recording enhancement system that reduces the amount of bias applied to the tape when it is recording a high-frequency signal because in tape recording, the amount of bias needed reduces at high frequencies. The Dolby HX Pro system, can, therefore, record high-frequency signals at higher levels and with less distortion. Since the system is a record-only system, no special equipment is required for playback of the tape. HX Pro lowers the amount of bias added during recording when the signal being recorded has a lot of high frequencies. This allows high frequencies to be recorded at higher levels with less distortion.




DOLBY NOISE:    This is a form of pink noise generated by a Dolby SR unit that is used for calibration purposes.


DOLBY NOISE REDUCTION:    The circuitry, electronic processes and electronic units that Raymond Dolby developed to remove the inherent low volume “hissing” sound that magnetic tape has.


DOLBY NR OFF, ON, DOLBY NR B, C:   (Buttons found on cassette decks.) These are the buttons that activate (turn “on”) or deactivate (turn “off”) the Dolby Noise Reduction (NR) system. Dolby B and Dolby C are different types of noise reduction. Dolby Noise Reduction is a process, developed by Raymond Dolby, used for analogue tape recording. This is because tape, regardless if it has any sound recorded on it or not, actually will produce a “hissing” noise as it plays. Even blank, unrecorded tape will make this noise. “Noise Reduction” electronically gets rid of this noise. It’s important to select the correct type on the cassette player. There are two types - “B” type and “C” type. Use “Dolby B” for all cassette tapes produced by Gold. Activate this feature of the cassette deck by pressing the “Dolby NR button“ to its “on” position (press it in). And then press the “B, C” button to ensure it is in the “out” position (which is for “Dolby B”). If you wish more information, there are detailed definitions of Dolby B and Dolby C as entries in this glossary.


DOLBY PRO LOGIC, DOLBY PRO LOGIC II:       (Also called “PL” or “PL II.”) This is the home consumer version of Dolby’s older style surround sound - also just called “Dolby Stereo” or “Dolby Surround.” Dolby Pro-Logic predates Dolby Digital Surround, but is still in use for video film releases and some TV broadcasts. (Dolby Digital is used in commercial theatres and for DVD-Video discs and home surround sound audio systems.) Dolby Pro-Logic is called “Pro-Logic” because it mimics Dolby’s original “Professional” surround sound system used for years in countless theatres around the world. The word “Logic” is used because it literally does do a type of computing (logic) to create the surround sound effect. Pro-Logic has the following surround sound channels - Left, Centre, Right, mono-surround (but with two speakers, one to either side of the home audience) and a subwoofer output (4.1). There is now a more recent version of Dolby Pro Logic, called Pro-Logic II. Pro-Logic II gives improved sound quality for the thousands of films already produced over the years in normal Dolby Pro-Logic. It is also better suited than the original Pro-Logic to accept two channel stereo music (such as a normal CD) and to convert its sound into surround sound. (Also note:    the “2.0 version” of Dolby Digital surround now handles the problem that the newer digital Dolby format of surround would not play over the older Pro-Logic - a problem for consumers who only had such older equipment.) The new Pro-Logic II will be found on DVD players too and this will allow the player to be adjusted to a “Dolby Pro-Logic II” setting that will play on the consumer’s older “Dolby Pro-Logic” equipment. Pro Logic II is Dolby’s direct competition with the DTS Neo 5 and Neo 6 systems.


DOLBY SEU4:       The Dolby Surround Encoding Unit - 4 (channel) is a professional level Dolby surround sound unit used in mixing a film’s soundtrack to create the original Dolby Stereo surround sound (non-digital). It is used in conjunction with a decoding unit called the Dolby CP65 that is installed in theatres to play back film soundtracks that are produced in the original Dolby Stereo format. It performs the electronic decoding and equalisation to produce surround sound in movie theatres.


DOLBY SOUND HEAD:       This is another name for optical sound head. (See OPTICAL SOUND HEAD.)


DOLBY SR:   This is the highest quality Dolby noise reduction system for analogue tape recording. It is a system that reduces recorded analogue tape noise and distortion. It gets rid of the “hissing” sound that tape inherently has when played, even when no recording is on the tape. This hiss, if not removed, is very audible. With Dolby SR, it is inaudible and high quality sound from the analogue tape format is made possible. For a technical explanation of exactly how Dolby SR works, see the Dolby SR manual.


DOLBY STEREO:  Many meanings! In the broadest and most common sense, “Dolby Stereo” is the trademark that appears on movies and in movie theatres that have any type, old or new, of Dolby surround sound. It is superseded by “Dolby Digital,” which has its own specifications and configuration. “Dolby Stereo” more often refers directly to the older Dolby surround sound format - also many times called “Dolby Surround.” In its home version, its name is “Dolby Pro-Logic.”

For a technical description of “Dolby Stereo,” read on… “Dolby Stereo” is where a given film has been released in prints that employ Dolby A-type Noise Reduction encoding. There are two tracks on 35mm stereo optical prints, referred to as Lt and Rt (Left total, Right total), which are matrix-encoded to contain four channels of information. The 4:2 encoding is done during the print mastering, with the 2:4 decoding occurring at the theatre. In their standard form, Dolby Stereo 35mm prints are encoded with A-type noise reduction. Beginning in 1987, Dolby Laboratories has made its Spectral Recording (SR) process available on 35mm stereo optical prints, with the advantage of greatly reduced noise and increased low and high frequency headroom. All of the stereo optical prints - Dolby Stereo (A-type), Dolby SR, DTS Stereo and Ultra Stereo - occupy the same area as standard mono optical sound and are capable of mono-compatible performance. The exact degree of mono-compatibility is mix-dependent. Dolby Stereo on 70mm usually means four discrete primary channels (left, centre, right, surround), with the left-centre and right-centre dedicated to “boom” information below 250 Hz. The four primary tracks are normally A-type encoded, although selected films since 1987 have utilised SR encoding on 70mm prints.        


DOLBY SURROUND:   The Dolby trademark used specifically for non-film usage, such as for videos and television uses. Also called “Dolby Stereo” or “Dolby Pro-Logic.” This is the older style Dolby Surround still in use for film video releases and in some theatres, but being rapidly replaced by Dolby Digital Surround. The new DVD’s will use the term “Dolby Digital Surround,” which is a newer type surround system.


DOLBY TEST FILMS:  Dolby Laboratories manufactures films with test programmes on them that are used to properly set up a theatre for playing Dolby-encoded films. Every Dolby format used in a movie theatre has its own test film.


DOLBY TONE:      A reference tone that is generated by a Dolby Noise Reduction unit and can be recorded on a tape that is recorded with Dolby Noise Reduction. The Dolby Tone is used to set the correct level into the Dolby unit for decoding on playback. This is done because volume level errors cause mis-tracking of the Dolby decoding function and degrading of the audio. 


DOMAIN:      The word “domain” as used here means a sphere of concern or function. One hears of “the analogue domain” and “the digital domain.” This means that all the audio or video is being handled digitally or by analogue means. “The mixboard keeps all the sound in the analogue domain.”




DONGLE:       Also called Copy Protection Key. It is a little wire that hangs off the back of a computer. It has a connector on it and some electronic parts are packaged in a little plastic box. The dongle has to be plugged into the back of the computer. If it is not plugged in, the computer will not turn on. The dongle is literally a key that unlocks the computer. It is a security protection device used in some computer programmes. 


DOPPLER EFFECT:      This effect is named after Christian Johann Doppler, an Austrian physicist who worked in the field of sound. Doppler Effect is the phenomenon perceived when the source of the sound is in motion in relationship to the listener. For example, if one stood near a railroad track when a train is approaching and the engineer blows the whistle, the sound of the whistle would change in pitch as the train approached and as it passed by. It increases in pitch as the train approaches and decreases in pitch as it passes by.


DOS:      Acronym for Disc Operating System. This is the way a computer functions and handles its operations - specifically, how the computer runs its memory, stores data on a disc, runs it’s programmes and interfaces with other computers. DOS was developed by Microsoft and was previously called Microsoft Disc Operating System. IBM adopted this system and since then, all operating systems for computers - especially IBM computers (including PCs) call their operating system “DOS.”


DOT COM (correctly written as “.com”):    A .com is slang for a business organisation or business individual who conducts his business entirely over the Internet by running a full feature Internet site. “She works for a dot com.”


DOT CRAWL:       Also called “zipper effect.” When the many small dots seen in a projected video image appear to crawl (move or shift) in position or the outline of the dots appears to vibrate and travel. “Dot Crawl” is much more noticeable on a large image as is made by a video projector, but it can also be visible on smaller TV and monitor screens. It is most visible when there are straight vertical lines in a picture. Instead of being perfectly vertical, small jagged dots will sometimes be visible on the vertical lines of an image. These can be seen if one looks closely at the picture. A type of picture that is more susceptible to dot crawl is when an additional image or caption is added to a basic picture. For example, in a newscast when you see the newsman on the screen and there is an additional image of what he is reporting on. If you look closely at the added image, you will often see unwanted artefacts on the vertical lines. These artefacts are in the form of small jagged points on the verticals of an image that seem to crawl around. There are moving jagged parts that appear to “crawl” around - and that is what is known as “dot crawl.” The scanning lines of the video cannot fully accurately track with the vertical image and additional unwanted artefacts are created.




DOUBLE (OR DUAL) MONO:    Reproduction of a mono signal through both channels, both speakers of a stereo system. Just because it is playing on both speakers does not make it stereo because the two speakers are playing the exact same source. (See STEREO.) Therefore, the sound will appear to come directly from between the speakers. It will not have the space or dimensionality of an actual stereo programme.


DOUBLE MUT:      A “MUT” is an acronym for Make-Up Table. When 35mm films larger than a standard reel that fits on a projector must be played, a special attachment is needed. In this case all reels are usually spliced together and the film is played straight through in one pass, without needing to change reels. One “makes up” the film into that one long continuous length - by splicing each reel’s worth of film together and in proper sequence. This is done on a “make-up” table. Really what the “table” is, is where one can take each reel, roll it out, and splice it to the previous reel for the film. Sometimes this is done on a motorised device that has huge (up to 4 ft in diameter) reels that are mechanically driven as one loads each consecutive reel to the large one on the machine. That machine is called a “double mut.” It is “double” because there are actually two reels that are mounted on the machine. One reel holds the film, and the other reel accepts (takes up) the film after it plays through the projector. After the film is all spliced together on one reel, the double mut machine is then wheeled over near the projector and the film is threaded through the projector and onto the double mut’s take-up reel. The double mut mechanically spins the reel in time with the projector, feeding film to the projector and taking up the film as it is played. There is a double mut in the Rushes Theatre.




DOUSER:       A metal screen that interrupts the light path in a movie film projector. The douser “douses” (cuts off) the light so no light appears on screen. When the film is ready to play, the douser is lifted and one sees pictures on the screen. At the end of a film, the douser closes.


DOWNCONVERT, DOWN-CONVERT:     The action of reducing (called “truncating”) the bit and sample rates of an audio and-or video programme so that its digital data will fit into a smaller package. An example of down converting is taking an original music recording done at 24 bit, 96 kHz and reducing it to 16 bit, 44.1 kHz for CD production. Another example is taking a High Definition video picture that was originally recorded at 1080 lines of resolution and reducing it to 600 lines for a television broadcast.


DOWNLINK: Receipt point of a satellite broadcast. Any point receiving a satellite broadcast, even a home consumer with satellite equipment, can be called a “downlink.” The receipt point is “linked” to the sending (broadcasting) point. It is called “down” because the signal is received coming “down” from the satellite up in the sky.


DOWNLOADING: To transfer or record a computer file. To stream audio or video content (media) off the Internet. 


DOWNMIXING, DOWN-MIX, DOWNMIXED:       1) A second mix derived from a surround sound mix, such as a stereo two channel version or a mono version. Also called a “fold-down” mix. The Mixer does these after the primary surround mix is completed. 2) The many channels of a DVD-Audio disc are “down mixed” to a version with less channels. (This does not apply to DVD-Video discs and players.) Digital Television broadcasts are often done in surround sound and special Dolby equipment is used to enable the surround mix to down mix on the consumer’s receiver. (See “SMART” FOLD-DOWN and METADATA for how downmixing is done by a DVD-Audio player.)


DOWNMIXING SWITCH:  A switch installed in a studio on or near the mixboard that allows the Mixer to hear, whenever the switch is turned on, what his full surround sound mix will sound like when downmixed to a version with fewer channels, such as a stereo two channel version for playing on normal stereo audio systems in the home.


DOWNTIME: 1) A period of time during which a system or piece of equipment cannot be used due to a failure in the hardware or software. 2) Nonproductive time, such as when technical equipment is idle but operational.


DOWNWARD EXPANDER: A piece of audio mixing equipment. (See EXPANDER.) A “downward” expander reduces the volume of the unwanted noise in an audio programme, but the meaningful sounds are NOT changed in volume. Examples of unwanted noise might be outside wind or a noisy air conditioner that was left on during a sound recording. A downward expander pushes the unwanted noise “downward” (in volume) but not the main recorded sounds. This is an ideal expander. Some expanders work differently. They push the unwanted noise in a recording to a lower volume, but at the same time, increase the volume of the meaningful signal. This latter type of expander can create problems with the loud parts going very loud and messing up the dynamic range. 


D + M & E:   An audio mix that has all dialogue, music and sound effects. Same as CM (complete mix).


DRAG:    When one audiovisual machine is connected to another or others so they are all operating together in synchronisation. There is a lead machine, called a “master.” The others are called “slaves.” The master is said to be “dragging” the slaves. This is done by the use of time code and the machines literally run at the exact same time together.


DRAM:   Abbreviation for Dynamic Random Access Memory. DRAM’s are used with integrated circuits containing capacitors. Because capacitors lose their charge over a period of time - meaning that the RAM would lose its memory once the capacitor discharged - DRAM chips have to be recharged (“refreshed”) continually. DRAM’s are referred to as “dynamic” because they are continually in motion in that electricity is kept flowing to the DRAM so it retains its memory and can thus supply data to the computer user. While a DRAM is being refreshed, it won’t transmit data to be displayed on the computer screen and one has to wait a bit. Despite being slower, DRAM’s are used more commonly than RAM’s because their circuitry is simpler and they can hold up to 4X the data.


DRAWMER:   A brand of mixing equipment. The company makes all types of compressors and other types of gear.


DRIVE:  The word “drive” means to control something or force it into motion or operation. It also refers to a mechanism that does the controlling or imparts the force in a mechanical or electrical object. 1) To feed an audiovisual signal to another piece of equipment - to “drive that piece of gear.” 2) Music or a mix can have “drive” when it is upbeat and has impact. 3) Short for a “disc drive,” which is the part of a computer that writes data onto and-or reads data from a floppy or other type of disc. A computer can also have a “CD drive” and a “DVD drive.”


DRIVER:       1) An individual speaker located, or to be located, within a cabinet. “He removed the broken driver and installed a working one.” 2) An electronic circuit that supplies an input to another electronic circuit. This is as opposed to just passing the signal with only a piece of wire. When a driver circuit is used, the signal is “driven” by the electronics. 3) A computer software programme that performs a specific function. For example, a printer that is hooked up to work with a compute requires a driver be installed in the computer for that specific printer. The software drives the computer function that operates the printer.


DR-1, DR-3, DR-8:       See NAKAMICHI.


DROP FRAME TIME CODE:       This is a type of time code used in audio-video production. Time code is a code used so that the audio and video machines run together with the same timing and start and stop together precisely. Time code is also used to show an operator precise locations on the recorded tape. To understand “Drop Frame” time code some TV video history is provided. In the early years of TV, before colour television sets, all public had black and white. Black and White TV runs on a TV video signal that has 30 frames a second - 30 individual picture frames per second, similar to how film has 24 frames per second. Well, when colour TV came out, all TV programming tried to broadcast in colour. The hope was that those consumers with black and white sets would receive the broadcast OK - just seeing it in black and white, not colour. It did not work out so well. The colour broadcast when seen on the black and white sets was ghosting - there were double images (ghosts) seen on the screen. This was because the frequencies of the colour signals interfered with those of the black and white signals. Technicians found, however, that if they reduced the frame rate just a little bit for the colour TV pictures, then the black and white sets would play OK. They literally had to “drop” frames. So, instead of black and white’s 30 frames per second (fps), they broadcast colour at just a little less - at 29.97 frames per second. This worked out fine for the broadcast. BUT, the studios making the programme to be broadcast were hit with a BIG problem. The earlier 30 frames per second was an exact time reference they had been using in their studios. They could easily use 30 and get their many different machines involved with creating a TV programme to work together. 30 frames per second was, to them, a stable datum. One frame of video = one 30th of a second. 30 frames of video equalled 1 second. 60 frames equalled 2 seconds, etc. This new 29.97 number was an oddball. The problem was compounded by the fact that TV and video studios all must get their equipment “talking together” using a common reference signal. This common reference signal would be sent to each piece of gear (camera, recorder, duplicator, everything and anything that would receive, process, or transmit TV video). With the common reference signal, each machine would be able to stay in comm. with each other. Without the reference signal, the TV pictures would jerk around and go unstable. The reference signal enables the equipment to keep all the video frames being processed at the same time, with the same timing - simple with 30 frames per second, but not possible with 29.97. The studios had been getting their reference signal for all equipment by doing a trick with the wall current coming from the electricity powering their equipment. Because the wall current operates at 60 cycles per second, they could use simple generators that would take that electricity and cut its frequency in half to run their timing devices. Exactly one half of 60 is 30 - and that corresponded with the 30 of the earlier black and white TV frames. They could therefore use the two different 30s to synchronise together all their equipment - it was their reference signal. To solve the problem, they decided to stay with the 30 frames per second reference signal for their studio equipment. The solution was to go ahead and do all the TV video shooting at the new 29.97 rate but they would use a time code that ran at 30 frames per second to give them their reference signal for their equipment. They worked out a way for the time code to “drop frames.” Every minute, the time code loses 2 frames, except for the 10th minute. They do this electronically. It allows the studios producing the TV video shots and shows to shoot in colour at 29.97 fps and that is what gets broadcast - so no matter what type of TV it’s received on, the picture looks OK (black or white, or colour). But the studios producing the shows, and all their equipment could still work as their equipment could still operate with a 30 fps time reference. The time reference (code) was simply made to drop 2 frames every minute except for the 10th minute - it works out as a match up to 29.97. Note:     Other TV video formats, like some used in the UK and Europe do not require drop frame time code.


DROP IN, DROPPING IN:        When recording an audio programme, such as music, it is often necessary to go back over a section of the recording and re-record it so that a perfect performance can be recorded. It usually doesn’t require that an entire piece be re-recorded, only a certain section. To do this, the recordist will go to that section and re-record (“drop in”) the improved performance. To site an example of why it’s called “dropping in,” let’s say a bricklayer has just laid a row of bricks. Upon finishing the row, he sees that it is perfect except for one brick in the middle of the row that is noticeably chipped. Before the mortar sets, he grabs a perfect brick, removes the chipped one and “drops in” the good one. Now he has a perfect row of bricks.     


DRUM MACHINE:        An electronic musical device, similar to a synthesiser, but used to produce a multitude of different drum sounds and percussion instrument sounds (shakers, cymbals, etc.).


DRY:      1) Having no reverberation or ambience. Describing an acoustical space:        deficient in reverberation or having a very short reverberation time. 2) More loosely used to describe an audio signal without any signal processing (meaning no mixing done to it.)


DSB:       Digital Signal Broadcast. DSB is a Digital Television (DTV) broadcast no matter if it is broadcast via satellite or with earth based transmitters and antennas. The term DSB is used in America. It is called Digital Video Broadcasting (DVB) outside the USA.


DSD:       Abbreviation for Direct Stream Digital. DSD is the format used in the Super Audio Compact Disc (SACD), which is Sony’s version of ultra-high quality digital audio. The other version is called DVD-Audio.) Both SACD and DVD-Audio use the same type of disc as their medium. Most DVD-Audio authoring is done at 24 bits and 96,000 samples per second. SACD uses a different approach with DSD audio. Instead of having multiple bit samples, DSD uses a single bit per each sample. The bit has 2 values - on or off. However, DSD has a sampling rate of 2.87 Megahertz per second. The theory is that this is so many samples that the audio resolution is virtually infinite and thus DSD sounds like analogue. The technology for processing audio at this rate is not new, dating back to 1977. What is new is that there is a medium that can actually store that amount of digital information. That medium is the SACD. The Super Audio CD is not actually a CD. It uses the same type of medium that DVD uses, a digital disc that can store 4.7 GB on a single layer. (DVD and SACD can have dual layers and even dual sides that are read by players equipped to handle these different layers.) USAGE NOTE:  Potentially, any digital audio starts out with a sampling rate of 2.87 Megahertz. However, due to the limited capacity of earlier digital storage media, this rate must be drastically reduced. Thus, conventional A to D and D to A conversion drastically reduce the rate of sampling. DSD simply bypasses the circuits in the converters that reduce the samples. Instead, the full 2.87 million sampling rate goes straight through. (These circuits are called “decimation filters” because they get rid of - “decimate” - the amount of samples in a digital datastream.)


DSL:       An abbreviation for Digital Subscriber Line. This is a telephone company technology that provides digital telephone service, internet access, teleconferencing and other features. “DSL” enables digital information to be transferred over land and satellite telephone lines. It can be used for phone conversations as well as the transfer of computer information. It can also be used to transmit audio and video to another computer.


DSP:       Abbreviation for Digital Signal Processing.

1) This term describes any changes (processing) done to an audio signal digitally. The changes are referred to as “digitally processing the signal” - thus “DSP.” Examples of types of DSP include equalisation, editing and changing volume levels.

2) Can also refer to equipment that does Digital Signal Processing or that DSP was used in mixing a sound. “I used DSP to create that sound.” “There should be enough DSP power in my computer to execute that edit.”


DSS:       Abbreviation for Digital Satellite System. This is the small satellite dish antenna needed to pick up satellite TV services as DirecTV or EchoStar. Hundreds of different stations are provided.


D-SUB (CONNECTOR):     A small rectangular-shaped connector usually consisting of two rows of connecting pins or holes, with one row slightly longer than the other one so that the top of the connector is a bit wider than the bottom. These connectors are often used to connect computer equipment.


DT:  An abbreviation for Digital Terrestrial and is a term used in regards to television broadcasting. Digital Terrestrial refers to any over the air broadcasting of Digital Television (DTV) that is not done using satellites or cable, but only with transmitters located on Earth that send signals directly to home antennas.


DTCP:    An abbreviation for Digital Transmission Copy Protection. A standard developed by the 5C working group (5C = 5 company) of Sony, Toshiba, Matsushita, Intel and Hitachi. DTCP is designed to give restricted access to recording equipment such as that using FireWire interfaces. It allows full access to display-only devices that will show the full, uncompressed high definition image. DTCP also includes within its System Renewability Messages (SRMs - defined separately) data on which exact devices are authorised to receive the signal, as well as any blacklisted devices.


DTLA:     An abbreviation for Digital Transmission Licensing Administrator. A company that authorises the types of devices that can receive high definition video signals, so as to prevent piracy. DTLA certifies devices such as set-top boxes, televisions, DVD players, etc. It also has Certificate Revocation Lists (CRL’s), which is its version of a blacklist of unauthorised devices. More data can be found at HDCP (High-bandwidth Digital Copy Protection) and DTCP (see above).


DTRS:    (Digital Tape Recording System). Tascam's term for describing digital multitrack tape recorders. (Tascam is a manufacturer of studio recording equipment.)


D to A CONVERTER (Digital to Analogue Converter):     The “D” stands for “Digital” and the “A” stands for “Analogue.” A “D to A converter” is an electronic circuit that converts digital information to analogue information. Every time you listen to a CD, you listen to it through a D to A converter. Without the D to A converter, the sound would remain in its digital form and could not be heard as audio. It translates the digital information into sounds that can be reproduced and heard on loudspeakers or headphones.


DTS (“dts”): The surround sound systems (equipment and methods) developed by Digital Theatre Systems of Westlake Village, California. DTS makes a professional surround sound systems that are used for commercial cinema theatres as well as a number of home surround sound formats for both film and audio releases on DVD. Their system relies upon DTS’ own proprietary digital format.


DTS CDs:      These are CDs that are mixed to play back in DTS surround sound - meaning one plays the CD through the DTS setting on one’s surround sound receiver or processor on one’s home theatre loudspeaker system.


dts ES, dts EXTENDED SURROUND:      DTS ES is a feature of DTS’ surround sound systems for professional and home use. This ES version of the DTS surround sound, when used for professional theatre applications, involves having synchronised CDs that play with the film. It is a compressed format - about 4 to 1 compression is applied to the film’s soundtrack. 


dts EXTENDED SURROUND 6.1 DISCRETE: DTS’ surround sound system for home consumers. Technically, it is exactly the same as the DTS ES system that is used for professional general cinema, but rather than using synchronised CDs with the film - as done in real theatres - the home version puts the DTS surround sound audio on the DVD disc and the consumer’s receiver, when set to “DTS Surround” decodes it and plays the audio to 6 channels plus one subwoofer. The DTS ES version adds a centre back channel to the surround sound. Note that it is still one channel less in the surrounds than Dolby’s THX EX surround format, which has two rear surround channels.


dts EXTENDED SURROUND 6.1 MATRIX:    This is for home consumers. The matrix version is specifically for taking DTS’ older digital five channel style surround mixes, and turning them into six channels using electronic processing. It competes with a similar system from Dolby, called Dolby Digital Matrix.


dts NEO 5 & 6 MATRIX SURROUND DECODING:      (See DTS.) Neo 5 & 6 are additional versions of DTS’ home surround sound systems designed specifically to provide up to six channels of surround from conventional stereo sources such as CDs, cassettes, FM, TV, or any other analogue or digital stereo source. “Neo” is a word that means “new or recent form.” In other words, DTS Neo turns “old stereo” into “new surround.” NEO:6 is for movie soundtracks and NEO:5 is for the stereo music sources. “Neo” is a trademark name of DTS. DTS NEO is directly competing with Dolby’s newest “Dolby Pro-Logic II,” which does the same thing as DTS NEO.


dts TEST FILMS: DTS (Digital Theatre Systems) manufactures films with test programmes on them that are used to properly set up a theatre for playing DTS-encoded films. Every DTS format used in a movie theatre has its own test film.


D3:  A type of professional digital video machine made by Sony. It is no longer being made. Some of the big video equipment manufacturers have developed their own digital video formats. Sony has their formats (D1, D2, D3, Digital Betacam, etc.). Some of these formats are no longer being produced.

For a technical description of D3, read on… It is a digital composite video format that records a digital signal at 8 bit resolution onto a ˝ inch tape. D3 has the same general quality level as D2.


DTV:       See DIGITAL TELEVISION for full information on DTV what it is and its relationship to High Definition television broadcasts.


D2:  A very large Sony digital video machine used for many years in the industry. The D2 is no longer being made. Some of the big video equipment manufacturers have developed their own digital video formats. Sony has their formats (D2, D3, DigiBeta (Digital Betacam), etc.).

For a technical description of D2, read on…D2 was the video standard for digital composite PAL or NTSC signals. It uses 19 mm tape and records up to 208 minutes on a single cassette. Not compatible with D1.  


D2 MASTER: Any final Edit Master originally done in the D2 format is often referred as the “D2 Master.”


DUAL LASER PICKUP:       This is a term used in DVD players that can play either a DVD-VIDEO disc or a DVD-AUDIO disc. These two types of discs normally can’t be played on the same player, but some players will accept both. Such players use two lasers inside, a different one for each type of disc.


DUAL LAYERED DVD:   Dual layer DVD’s have two separate surfaces (layers) for recording, storing and playing back digital information, and thus can hold considerably more data than a single-layer disc. Different versions of the programme can also be provided using the second layer, which, during the disc’s manufacturing is literally bonded (glued) on top of the disc’s first layer. The disc looks the same as a single-layered DVD. There are also DVD’s which have dual layers and dual sides. The first layer is “layer 0” and the second is “layer 1.” During playback, the DVD player’s laser reads layer 0 from the inside edge of the disc to the outside. Then the laser shifts its focus and reads layer 1 from the outside in. There may be a small glitch in the picture and sound when the laser shifts its focus to locate the second layer. A common single-layer DVD has 4.7 Gigabytes of storage capacity. Dual-layered ones have 8.5 to 9 Gigabytes.


DUAL LNB:    Dual Low Noise Blocking converter. A device inside a satellite dish that picks up the transmitted signal and routes it to one’s receiver box located near the TV set. The arm projecting from a satellite dish contains the LNB. This amplifier blocks low frequencies and receives high frequencies from 12.2 GHz to 12.7 GHz. A dual LNB means that there are two such units on the satellite receiver dish and these can then be used to send the signal to two separate TV sets.


DUAL SIDED DVD: A “dual sided” DVD is one the consumer must turn over to play a second or alternate side of the DVD. In other words, the DVD has information on both sides. For example, some DVD audio-video discs have a DVD-Audio version on one side and a Dolby, DTS or CD version on the other side. A dual sided DVD is not the same as a dual layered DVD. The latter need not be turned over. Rather, the laser in the DVD player can “focus” on different layers within the DVD and each layer has its own digital information. A dual sided DVD disc may also have dual layers on both sides. 


DUAL SUB-WOOFER: Two subwoofers playing stereo  bass signals. Can be said to describe two subwoofers playing the same signal (not stereo). It’s any time two subwoofers are in use.


DUAL STREAM DECODER (RECEIVER):        This is a type of receiver used to receive Digital TV. It is “dual stream,” meaning that it can receive and decode two separate streams of digital audio information simultaneously. A dual-stream audio decoder is required to receive programmes that are broadcast in foreign language versions. Two streams of audio are required - one for just the dialog and another for the music and sound effects. In a dual stream broadcast, one audio data stream is the soundtrack of music and effects (M&E) and the other audio data stream contains any of various translated dialog tracks. The two streams are blended together by the television receiving equipment, as chosen by the viewer (depending on the language he wishes). The Scientific-Atlanta company was the first to release such a receiver. 


DUAL-TRACE OSCILLOSCOPE:       An oscilloscope that can display two separate channels or wave forms, thus dual trace. The display lines are referred to as “traces” because they “trace” the signal and display it visually. Dual trace oscilloscopes are needed to calibrate any recorder that has two or more channels so that you can see one channel in comparison to another.




DUB:      The word “dub” comes from the word “double.” To make a “double” is to make a perfect copy of something. A dub means:       1) The action of copying a recording. 2) The copy of a recording. 3) To add dialog to a picture after the picture has been filmed or recorded on videotape; a procedure used to replace poorly recorded or unrecorded dialog and also to add foreign language dialog to a film.


DUBBING:    The re-recording of the original sound in a movie. For example, parts of a film’s dialog track may be re-recorded in post-production if the original sound recording is not usable.


DUBBING STAGE:       The studio where a film’s audio tracks are prepared and mixed.


DUCKING:    A trick for mixing voice and music together, such as for video soundtracks. The music is literally “ducked” (rapidly lowered in volume) under the voice whenever the voice speaks. When set properly, the ducking is not audible to the listener because it happens so fast. But it allows the general volume of the music to be kept quite loud while still being able to clearly hear the voice and all words spoken. Ducking is accomplished by using a graphic equaliser hooked up in tandem with a compressor-limiter. To learn how use ducking, one could set up the logs of an approved mix that used ducking and drill.


DULL:     Lifeless, muffled, veiled. Same as "soft”, only more so. The audible effect of high frequency (treble) roll-off (decrease) at around 5 kHz on up.


DUMB DOWN:      The intentional lessening of lines of resolution when feature films are broadcast for any sort of TV playback (satellite, cable, DTV or Internet). To “Dumb Down” is a form of copy protection required by some major film studios to prevent direct digital copying of films at high definition rates. Though the film may be produced for video playback at 1080 lines of resolution on the screen, the picture is intentionally reduced to only 600 lines.


DUMMY (SPEAKER) LOAD:      A “dummy” is a word describing a replacement that serves the purpose of the real thing, but does not actually fully work as the real thing. It is a “dummy.” A “load” is the burden that something must work to carry or hold. When a technician works on an audio amplifier, most amps should not be turned on unless a loudspeaker is attached. The loudspeaker is the “load” that the amp is designed to handle. A dummy load is attached while the amp is on the workbench. It is usually just a big resistor that has the same amount of resistance as a loudspeaker.


DURATRANS:       These are very large film transparencies. They are used on stages and film sets, usually as background scenes. The word “Duratrans” is short for durable transparency. A Duratrans is literally a huge photographic transparency of an image. These can be of such quality that, for example, an image of the Grand Canyon printed on a Duratrans as a background appears to the audience as if they are actually seeing the Grand Canyon.


DUVETYNE:  A fabric having a dense, soft or fuzzy surface made of cotton, wool, silk or rayon. This is the black fabric that is hung around equipment and anything in an event hall that needs to be covered up to look better.




DVCAM: Abbreviation for Digital Video Camera. A Panasonic video format for digital video. 


DVCPRO:      Abbreviation for Digital Video Camera Professional (version). This is Panasonic’s video format for professional digital video. It is not a High Definition video format.


DVCPRO HD:        Abbreviation for Panasonic’s Digital Video Camera Professional High-Definition (version).


DVD - the Digital Versatile Disc, what it is:      “DVD” stands for Digital Versatile Disc. Originally, when the first film was released in the DVD format, the disc was called “Digital Video Disc,” but the industry rapidly retracted the name because a DVD can be used to store all kinds of different video and audio information. It is “versatile” in this respect. Therefore, the disc is called the “Digital Versatile Disc.” The DVD has 7 times the storage capability of the CD. It can play up to six channels of audio. There are many different types of DVD’s. These are listed under the glossary entry, “DVD TYPES OF.”

Additional data:    As for the history of DVD, it really started when the first CD’s appeared in the early 80’s and many persons dreamed of someday being able to do away with video cassette tapes and put movies on a CD-like disc. In the late 80’s a “High Definition CD” was produced and many hoped then that the day would come when a CD could hold a complete Hollywood film. But it was not until years later that the hope turned to reality. The first “DVD-Video Disc” was introduced, in Japan, in November of 1996 and in the USA in 1997. Since then, DVD-Video has literally become the largest and fastest selling consumer electronics format of all time. DVD-Video players reached sales of over 10 million a year in just three years. (Even the colour television, home video deck and the normal CD took off much slower.) There are many different types of DVD’s, and these can hold different types of information. For example, a DVD-Video disc can hold a full film, surround soundtrack and different versions of the pictures and soundtrack. It can even be used as an audio-only release format (for music). In December of 1995 a group of technical representatives from major audio electronics companies formed the “Working Group 4.” This included Sony, Pioneer, Toshiba, JVC, Panasonic, and others. At the same time, another group formed too called, “The International Steering Committee” who sought to “steer” the industry towards a higher quality replacement for the CD. Together, these groups met and came up with the “DVD-AUDIO disc” - a DVD quite different from a DVD for video. The DVD-AUDIO disc is specifically for music releases, however it will hold video footage and graphics as well. All the different types of DVD’s look like a CD but the DVD has much higher storage capacity than the CD - almost 7X. And there are DVD’s that can hold even more information - with more “layers” of digital information able to be stored. What is a DVD disc exactly? Most persons think a DVD is a shiny metal disc coated in plastic and that the metal itself contains digital information that a CD player’s laser can “read.” In actual fact, the digital information is embedded (moulded) into the plastic inside the disc and then a very thin layer of aluminium coating is applied on top of that moulding, and yet another layer of plastic is applied on top of that (on top of the aluminium) to fully form the disc. The visual and audio information on a DVD is broken up, by computerisation, into many individual segments for each second of its length. These segments are called “samples.” These individual visual and audio samples are each converted into a digital code. This code is represented on the DVD by billions of microscopic pits that form a tight spiral track in the plastic. As the disc spins in a DVD player, a laser beam follows the track of pits. The light reflects off the DVD, and a light-sensitive device turns the different reflections into electric signal pulses. These pulses correspond to the original digital code and are then converted to signals seen over a TV screen and heard over loudspeakers. A DVD, like a CD, is 12 centimetres across. A DVD can have pictures (a movie or video), plus sound, plus up to 32 different subtitles or other printed information on the screen. While a DVD can store more data content than a CD, it can’t store an entire film unless the film receives a special process, called “compression.” Without compression, only about 15 minutes of a movie would fit! The film’s soundtrack is also compressed, for it too would not fit otherwise, especially with all the film’s picture information too. Literally, the digital data is “compressed down” so as to fit on the small DVD disc. DVD exceeds videotape cassette movies - picture quality-wise and in terms of audio quality. However, the pictures on a DVD are not classified as true “High Definition.” The term “High Definition,” for TV-video, means the picture meets certain very high specifications upwards of 1080 lines of resolution on the TV screen. (A DVD-Video disc can only produce 480 lines, which is still quite good and far better than normal video and TV broadcasts.)


DVD-A:  This is a shortened name for DVD-Audio. See DVD-AUDIO.




DVD-AUDIO DISC:     This is a specific type of DVD developed especially to release music in surround sound at very high quality. It is not a video DVD disc (called the DVD-Video disc) however, the DVD-Audio disc can contain pictures, graphics and text in addition to music. The DVD-Audio disc offers superior sound quality over DVD-Video discs no matter how well the DVD-Video disc is prepared, though a DVD-Video disc can have very high quality sound as well. Digital discs are rated by how fast they can accept and release information. This is called “transfer rate” and the DVD-Audio disc’s transfer rate is faster than a DVD-Video disc or a CD. Therefore, a DVD-Audio disc can deal with higher amounts of digital data. It’s not that more total data can be stored on DVD-Audio than a DVD video disc - it’s how fast data can be gotten off the disc. And, as the DVD-Audio disc is so much faster, it can have very high audio quality, even better than the DVD-Video disc. Therefore, the audio on a DVD-Audio disc does not need to be compressed and processed the way audio is on a DVD-Video disc. The two discs are produced differently and because of these different processes, a DVD-Video player cannot play a DVD-Audio disc. It just won’t read the DVD-Audio disc’s data. One needs a DVD-Audio disc player, or a “Universal” player that is designed to play both types. Due to this fact, and because so many consumers have only DVD-Video players, some music production companies are putting out DVD-Audio discs with a second layer of information that will play on a DVD video player. Another company is using a dual sided DVD and putting a CD version on the flip side of the DVD-Audio disc so consumers can play it in a CD player, providing they play the DVD-Audio disc upside down.

Additional data:    The DVD-Audio disc has certain exact specifications and capabilities that are unique. A DVD-Audio can have a dual-layer or dual-sided DVD disc for increased storage. This can accommodate a CD version of the audio, playable on a CD player, to exist on the DVD disc as well. A Dolby and DTS version can also be included. When a DVD-Audio disc offers a version of its music that can play on a DVD-Video player, in addition to the DVD-Audio version playable only on a DVD-Audio player, the DVD disc is said to be a “DVD-Audio Video Disc.” This simply means its content has versions that will play on the DVD Audio players and a version or versions that will also play on normal DVD-Video decks. Offering different versions of the music is now being done by some music companies, such as “5.1 Entertainment” in LA. They are releasing older music titles, remixed in surround sound for DVD-Audio, but including Dolby and DTS versions on the a second layer of the disc for consumers who do not yet have a DVD-Audio player but do own a DVD-Video player. (These consumers will not be able to hear DVD-Audio surround sound, but they will be able to hear a version processed with Dolby or DTS methods on their DVD-Video player.) DTS itself is also now releasing DVD-Audio discs. They utilise a data compression called Meridian Lossless Packing - just like all other companies producing DVD-Audio releases, and they are in 5.1 surround sound. However, the DTS DVD-Audio discs also includes, on a second layer of the disc, a DTS 5.1 surround version and a stereo version (using Dolby Digital processing). Another company, called AIX Media Group, is using dual sided DVD discs for their DVD-Audio releases. The consumer plays one side of the disc for the high resolution DVD-Audio music, or he can flip over the disc and insert it into his DVD-Video player and have a choice between a DTS or Dolby Digital surround sound version. Most companies involved with DVD-Audio production are producing their discs using dual layered or dual sided DVD’s so as to provide the different versions of surround sound consumers may be able to play in their home systems. (Note: some companies are not bothering to provide other than the DVD-Audio mix on their DVD-Audio releases.)

Sony has a digital disc which directly competes with DVD-Audio discs. Sony’s disc actually uses a DVD disc too, but the disc is called “Super Audio CD” (SACD). Both these formats create surround sound music using advanced digital processes that have higher audio quality than Dolby and DTS surround sound. Like most DVD-Audio discs, the SACD provides a second version (on a second layer of the SACD disc) that will also play in a CD player. However, unlike DVD-Audio discs, the SACD does not provide Dolby and DTS surround sound versions of the music programme. The DVD-Audio disc can include all versions; music in discrete DVD-Audio surround sound (which will play only in a DVD-Audio player), Dolby Digital surround sound and DTS surround sound (both of which will play on a DVD Video player and a DVD-Audio player), plus a stereo version (which will play on a DVD-Audio player, a DVD video player or CD player). SACD, on the other hand, has only a Sony DSD surround sound version (which will play in a SACD player only), and a stereo version (which will play in an SACD player, DVD-Audio player, DVD-Video player or normal CD player).

Some audio equipment manufacturers (i.e. Sony, Philips, Marantz and the Accuphase Corporation) produce players which will play DVD-Audio AND the SACD. A DVD-Audio player has six individual output connectors, one for each channel of surround sound. These six wires (for Left, Centre, Right, Left Surround, Right Surround and Sub-Woofer) route directly to the pre-amplifier, then to amplifiers and loudspeakers. Consumers purchasing DVD-Audio players must also ensure their pre-amplifier accepts the six discrete inputs. (Most all consumers with home surround sound systems presently rely entirely upon Dolby and DTS processing, but DVD-Audio does not involve the use of such. Dolby and DTS route their audio from DVD-Video players to the consumer’s pre-amplifier using just one wire. That one wire routes a digital stream of data that contains the entire Dolby or DTS surround sound mix. The consumer’s pre-amplifier decodes that one stream, splits it up into all the channels necessary for surround sound, and then the pre-amp routes the audio to amplifiers and loudspeakers. Because DVD-Audio is not made with Dolby or DTS processing, Dolby and DTS processing must be bypassed by the consumer and not used when listening purely to DVD-Audio disc content. All the newest surround sound audio equipment is being provided so as to accept DVD-Audio’s six individual wires. The DVD-Audio disc can do all kinds of things. For example, it even has the ability to have written lyrics on a screen, select a portion of those lyrics and the song will play starting at the lyric highlighted. The DVD-Audio disc may have all manner of different digital rates (how many bits are available and samples per second are taken). Most DVD-Audio discs have the audio put on the disc using the Meridian Lossless Packing Compression system. (MERIDIAN LOSSLESS PACKING - MLP - is defined as its own entry.) While it is possible to make a DVD with no Meridian compression, the industry uses this system. Still, the DVD-Audio player will read a disc without MLP and an uncompressed DVD-Audio disc can be made. Many DVD-Audio authoring systems won’t make a non-MLP compressed DVD - due to licensing agreements with Dolby (the international licensee for the Meridian process). A DVD-Audio disc could be made with over 250 minutes of stereo audio programme 24 bit, 96kHz uncompressed. But remember, it will still only play in a DVD-Audio player (not in a CD player or DVD-Video player.) Even higher digital resolution rates than that are possible but the amount of time on the disc, when uncompressed, starts to drop radically. (At the DVD-Audio disc’s highest rate of 24 bit, 192kHz, it will hold only 64 minutes of uncompressed audio and that’s with no other information on the disc.)


DVD-Audio PLAYER:  Specifically for playing DVD-Audio discs. This player is designed to process DVD-Audio discs with Meridian Lossless Packing (MLP) compression. It will also play DVD-Audio discs that do not have MLP processing if such a disc is made. Different versions of the mix can be included on the DVD-Audio disc, or the player itself can be set, by the consumer, to “fold-down” the surround sound audio into a stereo version. Ideally the DVD-Audio player is meant to be hooked up with its channels not processed by any Dolby or DTS surround sound electronics. Rather, the audio is to be sent directly to amplification and then to loudspeakers using separate inputs on the receiver or preamp. But, if the preamp does not have this hook-up capability, the DVD-Audio player itself can create versions of the music that are compatible with Dolby or DTS and stereo audio systems. In other words, the DVD-Audio disc player has 6 outputs that ideally, if the surround receiver has such, get routed to 6 discrete inputs of the surround sound receiver or processor. This will bypass the Dolby and DTS processing. If the audio system does not have discrete inputs on the receiver, then there is a digital output on the DVD-Audio player that can be used for Dolby or DTS surround sound, and it has an analogue stereo output as well. The digital output will allow the receiver to receive a Dolby or DTS version of the music on the disc, as created by the player itself by the player’s SMART FOLD-DOWN setting. Some DVD-audio discs will have Dolby, DTS, stereo versions of the music put right on a second layer of the disc itself so that the disc will also play in a normal DVD video player and not require the use of an actual DVD-Audio player. The two players are different and a DVD video player will not read the actual DVD-Audio disc’s main music programme. A DVD-Audio disc player does not play DVD-Videos and vice versa, unless a “Universal player” is used that will play all digital discs including normal music CD’s.


DVD-AudioV, DVD AUDIO VIDEO DISC:      Stands for “DVD-Audio-Video.” When a DVD-Audio disc offers a version of its music that can play on a DVD-Video player, in addition to the DVD-Audio version playable only on a DVD-Audio player, the DVD disc is said to be a “DVD Audio Video Disc.” This simply means the DVD Audio disc contains versions of its contents that will play on a DVD Video player. Some DVD Audio Video discs are dual layer, meaning one layer of digital data on the disc has the DVD-Audio content and another layer has the digital information that contains both the Dolby and DTS versions which will play on a DVD-Video player. Other DVD Audio Video discs are dual sided, meaning that the consumer must pick which side of the disc to play and turn the disc itself over and play the desired side. (One side has DVD-Audio data for playing in a DVD-Audio player and the other has the Dolby and-or DTS versions intended for DVD Video players.) 

Note:     When a dual sided DVD disc is used, the printing on the DVD itself can only be in the very centre of the disc as the laser of the DVD player cannot read the disc’s information through printing on the disc itself. Therefore, the only “open space” for printing on the disc is in its centre, just near the centre hole itself.




DVD CCA:      DVD COPY CONTROL ASSOCIATION. This agency is backed by the Motion Picture Association of America to help develop and enforce methods of protecting DVD’s from being illegally copied or played. They can be reached on the internet at


DVD CHANGER:   A DVD player that can hold more than one DVD.






DVD DRIVE, DVD ROM DRIVE:       A DVD player for a computer. The use of a computer to play a DVD often results in better picture quality than a normal DVD player, because the information can be kept digital all the way to the projector and not converted to an analogue video signal, as is done by a normal DVD player. For technical information on configuring a computer to play high quality DVD presentations, see HOME THEATRE PERSONAL COMPUTER. A DVD drive will also play CD’s. A CD drive will not play a DVD. There is no drive presently available for playing DVD-Audio discs in a computer. These require a DVD-Audio player or “Universal” player - one that plays all types of digital discs. Although DVD drives are very common on PC’s, most computer software still comes on CD-ROM (which DVD drives can also read).


DVD ENTERTAINMENT GROUP:     An organisation that keeps track of DVD usage by consumers and advancements in the field of DVD, especially as they relate to consumer usage and sales of DVD products. They hold a yearly convention and issue “Di Vi Awards” (Digital Video Awards) to terminals in the DVD industry with stellar accomplishments for the year.


DVD FORUM:       The original name of WORKING GROUP 4, one of the main groups who originated the DVD-Audio format. See WORKING GROUP 4 for details.


DVD-5, DVD-9, DVD-10, DVD-18:  A DVD with 5, 9, 10 or 18 Megabytes of digital storage capacity. The conventional DVD-Video disc that one rents to watch movies has 4.7 Megabytes of capacity - a single-layer, single-sided disc. (See DVD LAYERS.) The DVD-9 and DVD-10 require two layers on a single side - 2 layers being the maximum layers per side. The DVD-18 is a double-sided disc, each side consisting of 2 layers. The DVD-18, which has an 18 megabyte storage capacity, is currently the highest capacity DVD disc.


DVD’s how they are made and how they work:       There are many production steps involved in producing a Digital Versatile Disc. By knowing how a DVD is made, it is also possible to fully understand how the DVD actually creates pictures and sound when played in a DVD player. The list below contains, in sequence, the basic steps involved in producing a DVD, after which follows a description of how a DVD is then able to play visual and audio information. 




(Note:    The production sequence of preparing and manufacturing a DVD can be done in several different ways, depending upon methods and software used. Certain aspects are also advancing and simplifying in the industry too. The steps below are generally sequenced and applicable to most DVD production.)  


1) The production of DVD Video discs starts back when the film itself is completed. Once the film is edited for general motion picture theatre release, a version for DVD is often prepared. Additional scenes may be added, parts originally left out may be put into the edit, etc. There can be different versions for different countries. (For example, the movie “Pearl Harbour” had some offending comments about the Japanese removed for the film’s release in Japan.) The soundtrack is made to match the DVD film edit too. If the soundtrack was produced in Dolby Digital (most films are), that soundtrack can be used directly on the DVD - the Dolby process is actually the same for theatres and DVD discs, though adjustments may be made by the Mixer to better play in home environments. More importantly, “metadata” is created by the Mixer for the DVD’s audio soundtrack. (Metadata is digital code information that gives instructions to the DVD player on how to play the soundtrack in stereo or mono, if the consumer selects other than the surround sound version. If a DTS soundtrack is required, this will also be prepared for the DVD. But note that the disc will not store a full Dolby surround soundtrack plus a full DTS surround soundtrack. There is simply not enough room on the disc. Therefore, if there are to be the two versions, the DTS soundtrack will be created at a lower than normal digital rate (about ˝ DTS’s normal digital quality level). There may be additional pictorial information and audio required for the DVD, such as a Director’s Commentary or a “Making Of” [the film] video. These are also prepared. The film is also translated and a computerised list of all the subtitles to appear on the screen created, with exact timings is generated.


2) The entire film’s pictures and audio are transferred to video using the telecine process. This is a critical production step, one where final adjustments in colour and picture can be done. A DVD only produces pictures at 480 lines of resolution on the screen, but often the telecine process is done at far higher resolution rates. There is good reason to do so. First, the telecine process creates a digital archive copy of the film on video tape at the highest video quality possible. Also the film may be broadcast over Digital TV which can accept much higher resolution rates than a DVD disc offers. (Digital TV can broadcast up to 1080 lines of resolution.) By having a telecine of the film at the highest possible video resolution, one is able to produce or air the film at any resolution desired in the future, as well as produce a version converted for DVD release. 


3) With the film now telecined and all other information to exist on the DVD fully prepared, the process of “DVD Authoring” occurs. Just as a book must be “authored” (written), so must a DVD as there are so many different parts that make up its contents. Unlike a CD that has only music information that is easily transferred over for inclusion on a Compact Disc, the DVD has many different items such as the film itself, its soundtrack and soundtrack versions, subtitles, Director’s Commen­tary, “The Making Of” videos, interviews, etc. Also, films on DVD are usually broken down into “chapters” and a menu must be created so the consumer can select what he wants to see on the DVD and what soundtrack, subtitles, etc. In other words, the DVD’s must be “authored” (all its elements put together).


4) It is at this point too that all the picture information to be on the DVD is processed so that the DVD disc can actually store such. This is done by a “Video Compressionist.” A DVD is really quite small, and in order for it to store a complete film, its surround sound soundtracks, and all else on the disc, the digital information containing such must be reduced - “compressed.” Thus, the visual information to go on the DVD is converted to MPEGinformation. (MPEG=Moving Pictures Experts Group, which is a group of technical specialists who developed a method of reducing the amount of digital information required to digitally record picture information. This is called “compression” as the data is literally “compressed” - made smaller so the entire film and all other visual information can fit on the DVD disc.) The Video Compressionist plays back the telecine of the film (and other footage to be included on the DVD). He has the ability to compress some scenes more than others. For example, a fast action sequence are compressed less so its clarity and resolution is better while a static shot of a man sitting can be compressed more. The Video Compressionist’s job is to convert the film to MPEG, but in doing so, he works to compress the film as little as possible as compression does affect quality.


5) The MPEG film, plus all other visual footage to be included on the DVD (which is also converted to MPEG), can now be used by the Authoring Engineer. He puts it all into a computer file, complete with all the needed instruction codes and various other information that must exist on DVD in order for it to work fully in the consumer’s DVD players.


Note:    For an audio only surround sound release on DVD, a special DVD disc is used called the “DVD-Audio disc.” Music for DVD-Audio discs is processed by “Meridian Lossless Packing,” a special form of digital compression available through Dolby Laboratories specifically and only for DVD-Audio programmes. See MERIDIAN LOSSLESS PACKING for a full definition. There are some music DVD’s however that are put out on normal DVD-Video discs containing music. Such discs contain Dolby and-or DTS versions of the music, if in surround sound, and are not DVD-Audio discs, and do not use Meridian Lossless Packing. DVD-Audio discs require their own special player and will not play on a DVD-Video player, unless that player has been specifically designed to play both types. Music only releases on any type of DVD disc usually receive audio mastering, just like CD music, before activating the DVD production process.


6) When the Authoring Engineer has completed authoring the new DVD on his computer, he creates a master digital recording of the entire DVD’s contents. This recording is called a Plant Master and will be used to replicate the thousands of DVD discs to be sold to consumers.


7) The Plant Master is then sent for “Glass Mastering.” This is done by a company which specialises only in glass mastering or by a DVD replication facility that does glass mastering in addition to running mass volume DVD’s on replication machines. 


8) In the first step in glass mastering, a glass disc that has a light-sensitive coating is used. The glass master is bigger than a normal DVD, being 20cm in diameter and about 6mm thick. The coating of light-sensitive material is 150 microns thick and its uniformity on the disc is very important. The coating is baked onto the glass, which also makes the coating very hard. A laser is then aimed at, and “fired” at the glass disc. (Actually, it is fired at the light-sensitive coating on the glass.) The laser shoots in bursts. Its beam is “modulated,” meaning the laser is started and stopped by being instructed how long to fire and how long to remain unfired, based upon the Plant Master’s digital Binary number information. The Plant Master’s different binary numbers each cause the laser to start and stop firing differently. In this way, the laser’s “pulses” actually create an exact representation of the Plant Master’s binary information on the light sensitive coating. When the laser’s light is “on,” a tiny spot on the light-sensitive coating is “exposed,” Where the laser is “off,” the coating remains unexposed. The glass itself is unaffected by the laser, only the coating is affected.


9) The light-sensitive coating on the glass is actually called a “photoresist coating,” meaning that wherever the coating was NOT exposed to the laser’s light, that part of the coating will later “resist” being removed or rubbed off from the glass master. Therefore, after the coating has been “shot” by the laser, it is then processed, similar to how photographic film is developed, and anywhere the coating was exposed (“shot” by the laser), the coating is made to disappear. In other words, where the coating was exposed to the laser’s light pulses, the coating is removed. This leaves small microscopic “pits” in the coating right down to the glass. And, the unexposed areas of the coating remain on the glass. 


10) The unaffected coating areas exist between the pits and are called “lands.” Therefore, it can be said that “pits and lands” are formed on the surface of the glass master disc, right in the coating itself. For every DVD, there are billions of pits created by this process. The pits and lands vary in length. This is because the original binary information coming from the Plant Master tells the laser to remain “on” (or “off”) for different lengths of time. As such, a unique pattern of pits and lands, each with different lengths, is created which corresponds precisely to the unique binary number information from the Plant Master. (Later, after the final DVD’s are made, this pattern of pits and lands will be read back by a consumer’s DVD player to once again create the original Binary number information that was provided by the Plant Master. Binary information is easily converted to pictures and sound - the conversion process being the whole basis of digital audiovisual systems and explained in more detail in later steps below.) (Also see BINARY, BIT and DIGITAL. for full information on how sounds and pictures are recorded and played back digitally.)


11) Next, a layer of metal is then gently created over the glass master’s coating of pits and lands. Electrolysis is used - electricity allows molecules of the metal to build up over the glass master. (Another similar process, called “sputtering,” is sometimes used as well.) No heat is involved. The metal coating is allowed to thickly build up before it is removed from the glass master. (See ELECTROLYSIS, SPUTTERING for more technical information on these processes.)


12) This metal coating is now called the “Metal Master” or, more commonly, the “Father.” It is an exact duplicate of the pits and lands created in the light-sensitive coating on the glass disc. However, the metal Father is actually opposite, meaning a negative image of, the original glass master. (Like a print of your hand in mud, the Metal Master - the Father - has an opposite imprint of the glass master’s pits and lands. The Father is therefore said to be a “negative image” of the glass master.)


13) The Father is then used to create a “Mother,” similar to how the Father was produced. The Mother is an exact copy, made of metal, but it is an opposite image of the Father.


14) The Mother is then used to make “Sons,” using a similar metal coating (plating) procedure. Each Son is a negative image, exactly copying but opposite to the Mother. More than one “Son” is made, as Sons are the actual Stampers used to “stamp” (mould) the thousands of final DVD copies for consumer release.


15) The full “glass mastering process” is now complete. The glass disc, upon which a light-sensitive coating was turned into a pattern of pits and lands by a laser, has been used to create a Father, then a Mother, then Sons (“Stampers”) to be able to produce the thousands of DVD’s sold to public. DVD discs are often dual layered - meaning there are actually two “layers” of pit and land tracks in order to hold all the digital information required for a complete film and its soundtrack plus versions and extras, such as interviews with actors, director, etc. This means that the glass mastering process must be repeated for the second layer. Some DVD’s are dual layered and dual sided. With such a disc, a DVD-Audio release can have a “flip side” that will play in a normal CD player. For each layer, and for each side, the glass mastering process is repeated. Eventually, when the final DVD’s are replicated, the two layers (and two sides) will literally be bonded (glued), one on top of the other, to create the final DVD.


Note:    A Father or a Son can be used as a Stamper. Both are made of metal and both have a “negative image” of the original glass master. While the Father may give just a bit better sound quality than a Son (the Father is a direct copy of the original glass master), it is a fact that Stampers can only create a certain number of DVD’s before they become worn. By having and using multiple Sons, more final DVD’s can be produced without having to repeat any glass mastering steps.


16) Now the DVD’s can be replicated in volume. To do so, the Stamper (a Father or a Son) is mounted in a moulding press. Hot melted plastic is injected and the plastic takes the form of the Stamper. (This will be the final DVD the consumer can play at home.) Note: Because the Stamper has a negative image of the glass master’s pits and lands, and the moulded DVD is an opposite (mirror image) of the Stamper, the final DVD actually has a positive image, just like the glass master created by the laser originally.


17) Each final DVD is finished by applying several successive layers upon the new moulded (“stamped”) plastic. One layer is a thin coating of aluminium, which is used to reflect the laser beam within DVD players that will eventually play the disc. Other layers are also applied to bring the DVD to its final form, including a protective layer of plastic over the aluminium, creating the top surface of the DVD upon which label printing is then added.


Note:     It is actually the top, where the printing is located, that is the most sensitive part of the final DVD. (Most consumers think the bottom, where the laser strikes, is the most important side to protect from scratching. However, it is the thin top protective layer just above the aluminium that is the most sensitive.) If the thin protective plastic coating (just below the printing on top of the disc) becomes scratched at all, molecules of air and impurities can work their way inside the DVD and deteriorate the aluminium, thus harming its reflectivity and degrading sound and picture quality. There is far more plastic on the bottom of the DVD so it is not so susceptible to allowing aluminium deterioration. However, deep scratches on the disc’s bottom, as well as dirt, oils and smudges, can block the laser from fully reading the disc and so the bottom must be kept clean and undamaged as well. Also, bending the disc severely can distort the aluminium coating inside the DVD thus degrading its sound and pictures. In summary, owners of a DVD should take care to ensure the disc is never scratched on its top (the printed side) as well as the bottom and that the DVD is never bent. (See CD’s and DVD’s CLEANING AND CARE for more information and technical data concerning disc storage, care and cleaning.)


Note:     For technical personnel involved with producing DVD’s, see the technical reference, “DVD DEMYSTIFIED” by Jim Taylor, published by McGraw-Hill. Also see, “PRINCIPLES OF DIGITAL AUDIO,” by Ken C. Pohlman, published by Sams.






When a DVD is placed in a consumer’s DVD player, a laser strikes the disc as it spins. The laser starts from the centre of the disc and moves outwards (opposite to how a vinyl record album is played on a phonograph). It is important that the laser beam read the disc at a constant unchanging speed, but due to the disc being smaller towards its centre with its diameter increasing towards its outer edge, the disc’s rotational speed must change as the laser moves outward. The disc is therefore rotated 500 times per minute when the laser first starts, and as it moves across towards the outside of the disc, the disc’s speed is steadily slowed to only 200 rotations per minute. The pits and lands of the DVD exist in a continuous line spiralling tightly out from the centre of the disc. There are about 50,000 tracks on a DVD, which are really just one track spiralling outward. (If the track of pits and lands were to be “un-spiralled,” it would stretch about 11.7 km!) The track is about 150 times more narrow than a single human hair and consists of a pit, then a land, a pit, then a land, etc., continuing all in a row. (If a DVD were enlarged so that its pits were the size grains of rice, which is roughly how pits are shaped (running length-wise), the disc would be over a mile in diameter!)

Each pit and land is a different length, forming a unique track that corresponds to the original audio information. As the laser beam travels along this track of pits and lands towards the DVD’s outer edge, it reflects off the bottom of the pits and the surface of the lands. These reflections are received by an optical sensor (a light sensor) located inside the DVD player. The light sensor converts the laser’s reflections to electrical pulses, and those pulses are then converted to audio and picture information by other electronic circuits also located inside the DVD player. But realise that when a DVD is played, it is actually played “upside down” compared to the original glass master! The laser is actually looking through the “bottom” of the DVD, at the backside of the pits and lands. (Remember, the DVD’s “top” is where the printing is yet the laser fires at the DVD through the other side; its bottom.) Therefore, the pits are actually upside down as seen by the laser. In other words, the pits are raised, not sunken, as viewed by the DVD player’s laser beam. And, because the pits are raised, the edges of each pit create tiny ridges, like a mountain’s cliff walls. The laser’s light reflects back easily all in one direction when it strikes only the flat horizontal surface of a land, or just the bottom of a pit (actually it’s the “top” of each pit - remember that the DVD is being played “upside down”!). But when the laser beam strikes a pit’s edge (technically called a “ridge”), the surface of the ridge is at a vertical angle to the beam. The ridges are right where a land ends and a new pit starts and where a pit ends and a new land starts. The laser’s “ridge reflections” go off in many different directions. But also, when the laser beam strikes a pit’s “ridge,” it also strikes some of the flat surface of an adjacent land and a bit of the ridge’s bottom pit surface too! These several different surfaces create many different reflections of the laser beam. And, because a pit has a different elevation to a land, all the reflections from these various surfaces are out of time with one another and therefore they tend to cancel each other out. (Vibrations of light and sound tend to cancel if they are out of phase with each other, and this is specifically designed to occur in the playback of a DVD - the player’s laser reflections are to cancel out when a “pit-ridge-land combination” is struck by the beam as opposed to reflections coming from just one flat surface such as a land only or a pit only.) The DVD player’s light sensor can tell when it receives full “in-phase” reflections coming back off a flat land or off the flat part of a pit. And, the sensor can also tell when it receives partial, “out-of-phase,” broken up reflections when the laser beam strikes a pit-ridge-land combination (those areas in the track where a pit ends or a pit starts, divided by a land). This then gives two types of light reflections:      1) Full reflections from a land or a pit, and 2) Partial (mostly cancelled) reflections when the beam strikes a pit and ridge AND land all together. Note the number TWO. That is the binary system once again! The DVD player’s laser produces two types of light reflections and these are then used to precisely recreate the exact binary number information that was on the original Plant Master. The light sensor receiving the reflections sends out electrical pulses when it detects full light reflections. However, when broken up partial reflections are received, the light sensor does not send out any electrical pulse. Therefore, the player’s light sensor provides “on” and “off” signals. Of course, that is how a computer works. In the field of computers, the binary number system is used. The binary system uses only two numbers (“1” and “0”) and those two numbers represent “on” and “off” of electrical pulses. A DVD player is a computerised device, so, once it has recreated the exact binary information “contained” on the DVD, it then quite easily converts that binary information to visual and audio information one can see and hear.


DVD-I, DVD-INTERACTIVE:    A DVD that has the facility for a user to participate in its recorded programme. DVD-I requires a computer plug-in card or a built-in feature in his computer that allows the user to access the disc’s contents.


DVDit! : A computer authoring software for creating DVD’s produced by Sonic Solutions. DVDit! can fully author a DVD. The DVDit! lets users quickly create menus, titles and combine audio and video and is compatible with most professional level computer files.


DVD LAYERS:       This refers to the technology developed originally by the 3M company that allows production of a digital disc with more than one recordable layer. To read the different layers of recorded digital information, the laser inside the DVD player shifts its focus to read the different layers in the disc. When the laser completes reading the first layer (called “Layer 0”) it then shifts and reads the second layer (“Layer 1”) from the outside of the DVD moving towards the disc’s centre. There can be a very slight glitch in the audio and picture when the laser shifts from the Layer 0 to Layer 1. DVD-Video discs are often produced with dual layers as they can contain much more than just a movie, such as interviews with actors and directors, etc. Also, for DVD-Audio discs, which require their own special player, some music companies are including versions of the disc’s music on a second layer of the disc that will play in a DVD-Video player.


DVD-MUSIC (discs):  This is a type of DVD that is primarily for music releases. It is also called or labelled DVD-AudioV (for Video), and is NOT the same as a DVD-AUDIO disc. It is really just a video DVD that has a music release on it. These types of DVD’s are played through Dolby or DTS surround processing. Visuals are included that play concurrently with the music. This type of DVD will play in a video DVD player, unlike DVD-AUDIO disc.




DVD PLAYER (for video), DVD VIDEO PLAYER: A unit that plays (does not record) a DVD. There are different players required for different types of DVD’s. Some players, called “Universal” players, will play all types of DVD’s.

For information on hooking up a DVD player, read on… It is important to know that a DVD-Video player is connected to the surround sound receiver in TWO different ways in order to supply audio information to the surround sound loudspeaker system. In order to use DOLBY DIGITAL or DTS or MPEG SURROUND digital surround sound processing in one’s surround sound receiver or processor, the signal is sent from the DVD-Video player to the surround sound receiver using one digital wire. This will be labelled ‘DOLBY” or “AC-3” or “BIT STREAM” or “BIT STREAM PCM” and is connected to the receiver or processor connector labelled “DIGITAL IN” or “AC-3” or similar wording. The DVD-Video players also provide a left and right analogue stereo outputs. (These two-wire connections are for Dolby Pro-Logic, the older Dolby version, as well as just listening to a stereo CD.) Also, there is usually a digital output on the back of DVD players that can be sent to an external D to A CONVERTER to improve the quality of sound when playing these special audio-only 24bit, 96kHz music discs and normal CD’s on a DVD player.) For best picture quality, if you have a TV or projector that will accept such, always use the COMPONENT or RGB video outputs. If the TV only accepts Super VHS, then use that. If it is an older TV and has none of these, then use the usual (poor quality) RCA or BNC connector composite video output. NOTE: Most commercially available DVD players do not have digital video outputs. They are intentionally designed to do a conversion to analogue to prevent direct digital copying of the material. The conversion downgrades the quality.  


DVD PLUS:    A DVD that has a movie recorded on it, including the film’s soundtrack, just like a DVD-Video. The “PLUS” is a separate audio-only recording of the music from the film that can be played back on a CD player. The DVD Plus is a DVD plus a CD.


DVD-R:  A DVD disc that can be Recorded on once. (Compare with DVD-RW.)


DVD-RAM (Random Access Memory discs):      This is the type of recordable DVD disc used by Technics and Panasonic DVD recorders. It will allow the user to erase the disc and re-record and the user can also only partially erase the disc and the recorder will seek out blank areas to re-record on. The drawback with this type of DVD recording format is that it will not play back on most other DVD players. Will play back on computer DVD drives.


DVD REGIONS:   This refers to how a DVD-Video disc is made playable only in certain regions (countries). Many films come out on DVD in the USA at about the same time they are released to theatres in the rest of the world. Releasing a film on DVD simultaneously in Europe and the US thus might discourage European theatre attendance. Each nation also has unique ways of handling films in terms of ratings, censorship - not to mention dubbing for foreign languages. To release the English version on DVD at the same time as all the non-US release actions is something the film industry sought to prevent. To prevent a DVD from playing in other countries, there were eight “regions” established to cover all parts of the world. When the DVD is produced, a code is installed on the DVD disc that enables DVD players in only certain countries to play the DVD. Players sold to consumers are given an internal code to only accept DVD’s for their region.


DVD-ROM:    Abbreviation for DVD - Read Only Memory discs. It can only play, it cannot record and cannot be erased. The DVD-ROM is intended for play or information transfer on computers rather than consumer DVD players.


DVD-RW (discs):       Abbreviation for DVD Re-Writable. This type of recordable DVD can be recorded onto and then erased and re-recorded onto many times. Requires it’s own special RW type recorder but will play on any player. More used for computer data and lower quality music recording where the consumer wishes to rerecord favourite songs, etc.


DVD + RW (discs):    Abbreviation for DVD Re-Writable, Plus. This is a recordable DVD format that will play on any DVD player. Requires a DVD+RW recorder. It will play on a p.c. with a DVD-ROM drive. Enables consumers to shoot home videos, edit them on their personal computers, record their video to DVD+RW on their computer’s DVD-ROM drive and then play them on their tv’s using the DVD player in their home audio system.


DVD SCREEN SIZES:  There is important data to know about DVD’s and the various screen sizes they can produce. (The data also applies to how Digital TV programmes are broadcast.) If a DVD-player is not adjusted correctly and if the TV is not adjusted correctly or of a certain type, the pictures from a DVD can look very odd - people in the picture on the screen can look very fat, buildings will wiggle, and when the camera pans across the screen there will be many distortions to the picture - if things are not set up properly. When you first set up (install) a DVD player, one of the first steps is to press its control buttons to select “4x3” or “16x9.” This tells the player what size TV you have or how you wish to project the image using a video projector. “4x3” means that you have a usual, normal, TV - these have a screen size that for every 4 cm wide, the screen is 3 cm tall. If you have one of the brand new types of wide-screen TV’s (made for High Definition TV), for every 16 cm the screen is long, it is 9 cm tall. DVD packaging will say what size screen image is recorded on the DVD disc. If it says “4x3,” FULL SCREEN or FULL FRAME, and you have a normal 4x3 TV, the picture will be correctly displayed. However, if the DVD packaging says “16x9” or “enhanced for wide-screen” or “Anamorphic” or “wide-screen Anamorphic” or “enhanced for 16x9 televisions” AND you only have the conventional 4x3 TV, then the player itself, because you selected “4x3” on the player’s controls, will not convert the picture to play on your normal TV screen size - it will make it letterboxed and the picture will not fill the screen but will have black areas above and below a long narrow picture on your set. If you have one of the new 16x9 TV’s, then set the DVD player to the “16x9” setting. Now, no matter what is on the DVD’s packaging, the player will send it along to your 16x9 screen. 16x9 display screens have a button that selects “4x3,” “letterbox,” or “wide-screen” - whatever the DVD itself was recorded with. It could be any of the three. Leave the player set to 16x9 and set the screen to the appropriate settings, per its manual. You never have to change the setting on the player, only the screen you are watching. If you are watching a DVD on a 4x3 TV and the objects in the screen wiggle and shake when the camera pans, it means that the DVD player is not a very good one at converting the wide-screen DVD pictures to a picture that can be played on a non-wide-screen TV (a normal 4x3). If you are watching a DVD on a 16x9 screen and people and objects look very fat on the screen, and objects wiggle, it means you have not set the DVD player to 16x9, but rather have it set at 4x3.

Additional note:    for best picture quality from a DVD player, use the component or RGB video outputs from the player and inputs on the TV, if your TV accepts such. The SVHS output is second best. If the TV is older and no such inputs exist, then you will have to use the lower quality composite video output and input (an RCA or BNC connector).


DVD types of:      (Note:    See DVD - THE DIGITAL VERSATILE DISC, WHAT IT IS for full information on the DVD format.) There are different names and-or types of DVD produced that are commonly heard about in the audiovisual industry. They are currently as follows:


The following is a list of all the names and different types of DVD’s commonly used and heard about within the industry. There is considerably more information on each type of DVD at the separate entries throughout this glossary and at the entry “DVD.”


hDVD Disc (High Definition)


An hDVD disc will store and play back standard definition TV-video, but it also can store and play a very limited length (running time) of high definition TV-video signals. Even with compression, an hDVD will hold only 15 to 20 minutes of HDTV programme on a single layer DVD disc, or 30 to 40 minutes on a dual layer. While a “dual-layer, dual-sided” disc could hold up to 70 minutes of programme, there are no current plans to produce any such discs. The hDVD disc format uses MPEG-2 compression to accomplish the storage and recording of both standard definition and high definition programmes, including 1080i and 720p scanning lines of resolution. hDVD is not yet released but for demo samples.




A DVD made for film and video playback. It can also be used as an audio-only format. This is the main type of DVD purchased and rented by consumers. A DVD-Video disc is the type that has a full motion picture and surround sound audio. It plays on a DVD-Video player. It can also be used for audio-only releases that will play in both a DVD-Video player or CD player, if specially authored as a dual-layer or dual-sided disc.




Made expressly for music releases in surround sound. Requires a separate player. DVD-Audio discs will not play on a DVD-Video player. Like a CD, its playing time is 74 minutes, but can be greatly extended if only intended for 2 channel stereo content, not surround sound. The audio information is not made with Dolby, DTS or MPEG compression, but rather Meridian Lossless Packing digital compression (MLP) is used. A dual layered disc and dual layered plus dual sided disc can be used thus enabling Dolby and DTS surround sound versions to be put on the same disc (which will play over a normal DVD-Video player. In this way too, a CD version can be included that will play on a CD player or any DVD player. DVD-Audio players have settings to provide Dolby, DTS and stereo versions of the music. A DVD-Audio disc may have picture, text and graphics too. It is intended to be played with all 6 of its full range audio tracks NOT processed by Dolby or DTS.


SACD - Super Audio CD (Sony)


This is Sony’s and Phillips’ competition to DVD-Audio. In fact it actually uses a DVD disc, but its information is recorded with a proprietary digital method developed by Sony and Philips. The SACD provides a second version, on a second layer of the SACD disc that will also play in a CD player. However, the SACD does not provide Dolby and DTS surround sound versions. More details at SACD glossary entry, in the S section.




This is a DVD-Video disc, however it has a music release on it and video pictures. Popular for recorded live concerts. Is not the same as a DVD-Audio disc. A DVD-Music disc is meant to be played through DTS or Dolby film surround sound settings on consumer equipment. Also known as “DVD-AudioV” and “Digital Audio Disc.” Pictures are MPEG 2.




A high quality 2 channel music-only DVD-Video disc with music at 24 bit, 96kHz uncompressed audio. These are played on a conventional DVD player. (Not the same as DVD Music Discs.)


DVD-AudioV or DVD-Audio-Video or DVD Audio-Video Disc


When a DVD-Audio disc offers a version of its music that can play on a DVD-Video player, in addition to the DVD-Audio version playable only on a DVD-Audio player, the DVD disc is said to be a “DVD-Audio Video Disc.” This simply means its content has versions that will play on the DVD Audio players and a version or versions that will also play on DVD-Video decks. A dual layer or dual sided DVD can be used.


DVD-i (Interactive) Disc


Any DVD disc that has interactive capabilities.




A DVD with 5 Megabytes of storage space. The conventional single-sided, single layer DVD disc that one rents for movies has this amount of storage space.






A DVD with 9 Megabytes of storage space. This requires that a DVD disc have two layers of information storage space. DVD-9’s are single-sided, dual layer discs.




A DVD with 10 Megabytes of storage space. This requires that a DVD disc has two layers of information storage space. DVD-10’s are single-sided, dual layer discs.



A DVD with 18 Megabytes of storage space. This requires that a DVD disc has two layers of information storage space on each side of the disc. DVD-18’s are dual-sided, dual layer discs.




A DVD with content written on both sides of the disc as opposed

to the normal one side only. The consumer must physically turn the disc over to access the information on the other side of the disc. (See DVD-18 above. See DUAL SIDED DVD for more information.)




A DVD that has two separate layers of digital information that the laser in the DVD player can focus on for additional information. The two layers are always on the same side of the disc. Frequently used to include both a surround sound (layer one) and a stereo version (layer two) of music on a DVD.


Audio DVD-R (Recordable) Disc


Recordable DVD discs sold on music market lines. Note that several  types of DVD recorders exist on the market presently. This is the type of disc used in Pioneer DVD recorders. They will not play back on most DVD players but only on computer DVD type drive or the recorder that made the disc.


data DVD-R (Recordable) Disc


Recordable DVD discs sold on computer gear marketing lines. Note that several types of DVD recorders exist on the market presently.


DVD-RAM (Random Access Memory) Disc


This is the type of recordable DVD disc used by Technics and Panasonic DVD recorders. It allows the user to erase the disc and re-record and the user can also only partially erase the disc and the recorder will seek out blank areas to re-record on. This type of DVD recording format will not play back on a conventional DVD player. Will play back on computer DVD drives.


DVD-ROM (Read Only Memory) Disc


This is really what any pre-recorded DVD you purchase is. It can only play, it cannot record and cannot be erased. The DVD-ROM term is used more in reference to DVD’s intended for play or information transfer on computers rather than consumer DVD players. May have

certain error correction on the disc designed more for computers.


DVD RW (ReWritable) Disc


This type of recordable DVD can be recorded onto and then erased and re-recorded onto many times. Requires its own special RW type recorder BUT may not play on any DVD player. More used for computer data and lower quality music recording where the consumer wishes to rerecord favourite songs, etc.


DVD+RW (ReWritable Plus) Disc


This is a recordable DVD format that will play on any DVD player. Requires a DVD+RW recorder. It will play on a PC with a DVD-ROM drive. Enables consumers to shoot home videos, edit them on their personal computers, record their video to DVD+RW on their computer’s DVD-ROM drive and then play them on their TVs using the DVD player in their home audio system. Probably won’t play back on DVD-RAM or DVD-R format machines.




A DVD that has a movie recorded on it, including the film’s soundtrack, just like a DVD-Video. (See DVD-Video above). The PLUS is a separate audio-only recording of the music from the film that can be played back on a CD player. The DVD Plus is a DVD plus a CD.


M-DVD Disc


Magnetic-DVD.” An early type of recordable DVD introduced in 1998 by Castlewood Systems of Pleasantwood, California, and Sanyo (an electronics company in Japan). The M-DVD was a predecessor to DVD-R and DVD-RW recordable discs. (See DVD-R, DVD-RW.) It was the same size as a DVD but could only hold a little under half a DVD’s capacity of digital information. M-DVD has been replaced by the DVD-R and DVD-RW, and is no longer on the market.


DVD-V (discs):    This is a shortened name for DVD-VIDEO. See DVD-VIDEO.


DVD-VIDEO DISC:      A DVD made for film and video playback. It can also be used as an audio-only format. This is the main type of DVD purchased and rented by consumers. A DVD-Video disc is the type that has a full motion picture and surround sound audio. It plays on a DVD-Video player. It can also be used for audio-only releases that will play in a DVD-Video player.




DVD ZONES: This refers to the several data storage “zones” available on a DVD such as a zone for audio, a zone for pictures, a zone for the menu, etc. This is not the same thing as DVD REGIONS. (See DVD REGIONS.)


DVE:       1) Digital Video Effects. When you see video pictures that do all kinds of graphic type effects or spin and twist about, or morph, they are called “effects.” DVE machines produce such effects. They have grown highly advanced with powerful computers. The list of effects varies, including zooms, rotations, 3D perspective, page turns, picture bending, mosaic patterns of many pictures on screen, etc. 2) Digital Video Enhancer - a feature on some home consumer DVD players that is said to enhance picture quality.


DVEous: Pronounced “devious.” DVE means Digital Video Effects. DVEous is a play on words for the name of a brand of equipment that produces high quality digital video effects. (See DVE.)




DVI:       An abbreviation for Digital Visual Interface. A high-speed interface designed to transport uncompressed digital video to a display. DVI’s capacity and speed (up to 5 Gb/s) can transmit uncompressed high definition video signals. By contrast, other digital interfaces require the h.d. signal to be compressed. Although originally intended as a high-speed interface for connecting computers to lcd, plasma and other digital displays, DVI has been adapted for use in the consumer market (i.e. set-top boxes, DVD players, etc.). In the consumer market, DVI is being used with a content protection protocol called High-bandwidth Digital Content Protection (HDCP - defined separately).




DVS:       See Descriptive Video Service.


DYNAMIC:    1) Sound that is “dynamic” is alive sounding. It can go loud and powerful and the next instant play a softly recorded sound. It has impact and draws the listener’s attention, as the sounds are real and interesting. Dynamic music gets one’s feet tapping as the rhythm and beat is alive and impacting. It has punch. 2) Said of a type of computer memory chip that requires continual electrical current to operate and will not store data without a constant supply of electricity. “Dynamic”, in this sense, means “continually in motion.” In order for the memory to be retained and available to the user, a continual charge of electricity must be supplied by its electronic circuit - it is the continually moving electrical charge that allows the dynamic memory chip to be in continual motion (retain and supply data). (There is a separate entry on DYNAMIC RANGE. This is not the same term.)


DYNAMIC AUTOMATION: Mixboard automation that is based on time code. It’s called “dynamic” because the mixboard’s controls are able to move by their own computer-automated mechanisms in reference to a precise point of time in the soundtrack, and do not require a person to do the turning of the dial once the original move is written and recorded into the computer. The mixboard’s computer stores the moves done by the Mixing Engineer at exact points of time, based on the hours, minutes, seconds and frames. For example, If an explosion occurs in a film soundtrack at 1 hour, 15 minutes, 33 seconds and 10 frames (1:15:33:10), and the Mixer writes a move for a fader (volume control) at that exact point, the mixboard’s computer will store it and replay the move at that exact time code point every time the mix is played back.


DYNAMIC FEEDBACK ARRANGEMENT SCRAMBLING TECHNIQUE:      Abbreviated DFAST. A term regarding Cable TV carrying Digital TV and High Definition TV signals to consumers. The Cable TV industry provides Digital TV to the home consumer market. In addition to its scrambling feature, DFAST also can take a High Definition signal (which can be upwards of 1080 lines of resolution on the screen) and down-convert it to far less resolution (600 lines). This is required by some movie copyright owners to prevent digital copying of high definition broadcasts.


DYNAMIC MICROPHONE: At the heart of any microphone is its diaphragm, where acoustical energy is converted into an electronic signal as the diaphragm vibrates in response to the impinging sound wave. Microphones are commonly classified according to the manner in which this energy conversion takes place. One of the most common classifications of studio microphones is the dynamic microphone. Dynamic microphones are those in which an electrical signal is produced by the motion of a conductor within a magnetic field.


DYNAMIC PANNING: A coined word in mixing, “dynamic panning” is where a sound is “panned” (moved across) from one loudspeaker to another, but done so by an automated feature of the mixboard that will turn the knob that does this very smoothly.


DYNAMICS PROCESSING:       The action of taking an audio programme and controlling its dynamic range during mixing. The Mixer has two basic tools he uses for this - the limiter and the compressor. (See LIMITER, COMPRESSOR, DYNAMIC RANGE.) 


DYNAMIC RANGE:      The dynamic range is a measure of the span between the quietest and loudest sounds an instrument is capable of producing or of a programme that is being put through audio equipment.


DYNAMIC RANGE COMPRESSION:        This is a feature (a process) on some DVD-Video players and home consumer surround sound receivers or processors that keeps the loud volume peaks heard in film soundtracks from getting too loud. Therefore one can set the volume of the film a little louder overall so as to hear the dialog and other lower in volume sounds well but not get blown out of the room if a really loud sound effect comes on.


DYNAMICS:  The amount of fluctuation in level (volume) of an audio signal. When music (or any recorded or mixed sound) is reproduced in a way that does not restrict its loudness while also allowing one to hear the softer (lower) volume sounds as well, it is said to have “good dynamics.” A tremendous orchestra that sounds huge and able to play very loud, or play very soft, has good dynamics. It also has to do with the speed with which the music or audio loudspeaker system can shift from loud to soft. The faster, the better and more lifelike. Some mixes and some audio equipment and loudspeakers can restrict dynamics. They can sound slow or compress the loud parts of the sounds. This is important in judging the quality of an audio programme and any audio loudspeaker system.


DYNAMIC SHADING: All musical instruments and singers, when combined in a well-mixed piece of music, have differences between each other in dynamics (loudness and softness) and differences within themselves in this regard. This is a quality that gives reality, life and interest to a piece when heard over loudspeakers or headphones. The perceived differences are referred to as “shadings” (similar to how colours have different shades in relation to other colours, even if similar in colour). Also referred to as “Microdynamics” and “Macrodynamics.” Dynamics can be divided into two categories: macro and micro. Macrodynamics are the big crescendos, those moments when all hell breaks loose and the music builds very loudly overall. Microdynamics, on the other hand, are the subtle differences, such as the variations between individual notes on a harp lightly played or the differences in how a pianist hits each key with a certain loudness, touch, or softness. An excellent loudspeaker system can reproduce both types of dynamic shadings and a good recording and mix has these qualities as well. Differences in volumes and impact of sounds contributes to their overall sense of reality and realism in audio.


DYNAMIC SWING:     An audio amplifier is said to have “good dynamic swing” when it can respond lightening fast to the loud and soft parts of sound. A slowly responding amplifier, common in very old designs, could not produce sudden loud passages accurately. It could not “swing” fast enough. It could not react with the power and speed required.


DYNAUDIO:  A loudspeaker manufacturer in Denmark. Dynaudio makes professional speakers for studio use as well as for homes. Their studio speakers are distributed by T.C. Electronics.


DYNE:    The dyne is a unit of force often used in measuring the sensitivity of microphones. Dyne comes from the Greek word “dunamis,” meaning power. One dyne is the force needed to move a particle (or group of particles) that weighs one gram a distance of one centimetre in one second. It is also equal to the pressure of one-millionth of an atmosphere  (an atmosphere being 15 pounds per square inch of pressure). A tiny unit such as this is used to measure the sensitivity of microphones because they respond to very small changes in air pressure in picking up sound.


DYNRNG, DYNRNG METADATA:     An abbreviation for “Dynamic Range” audio compression used for Digital TV broadcasts. Note:  This is not a type of digital data compression that reduces the amount of data to fit it into the storage or transmission capacity available, but rather compression the actual dynamic range of the audio volumes of a digital TV programme.) Digital TV (DTV) can have extremely high quality wide dynamic range digital audio, meaning the audio on digital TV broadcasts can go very loud but also have very quiet sections as well. However, there is a problem in providing such to home consumers. Many TVs have poor quality very small loudspeakers that cannot handle full range audio. On such loudspeakers, any sounds that are quite loud will distort the small speakers and force the listener to turn down the volume. But then it is difficult to hear the quieter parts. As well, TVs are often listened to in noisy environments like airports, kitchens, restaurants, etc. Therefore the TV’s sound has to be played somewhat loudly. This will cause small loudspeakers to distort quite rapidly when the soundtrack goes very loud. Therefore, the broadcaster of the DTV programme compresses the audio using a feature called “DYNRNG.” The loud portions of the audio are lowered in volume and the quieter sections are increased in volume so there is not such a wide variation between the two. In other words, with the “Dynrng” setting, the softer sounds such as quiet dialog are made louder while the louder - like gunshots - are made quieter so that one can hear the dialog in a noisy room without having the gunshots, etc. be overbearingly loud or so loud that they might harm small TV loudspeakers. The consumer can then set the volume on his TV and not have to constantly readjust it to turn down loud portions or to turn up quiet portions of the programme. However, if the consumer has an excellent loudspeaker system with high quality equipment that can handle the wide dynamic range of the audio programme, then the “Dynrng” can be defeated (by the consumer) -  returning the audio to its original dynamic range. DYNRNG is similar to, but not the same as “DIALNORM” Dialog Normalisation - see DIALOG NORMALISATION. Important Usage Note:  These types of compression are being included automatically on all DTV broadcasts. For example, all Digital TV receivers (encoders) will allow consumers to select settings for Dynrng and Dialnorm. Dolby E provides the way that this is performed by the encoders using “metadata.” Therefore, in preparing a soundtrack for DTV broadcast, a Mixer takes this into account and checks the mix with such settings.