“P” or “p”: You will see this in regards to TV video picture quality rates. Stands for “Progressive”. See PROGRESSIVE SCANNING.
PAC BELL ADVANCED BROADCAST VIDEO SERVICE: A service provided by Pacific Bell Telephone Company for transmitting video and audio signals. Pac Bell uses their telephone lines to send video from one point to another in California. They also interconnect with other companies’ fibre optics transmission lines and phone lines to transmit cross-country or internationally. In order to use this service, the customer brings his video or audio programme to the nearest Pac Bell central location. They also provide links from live venues to studios and broadcast stations.
PACKED PCM: This term can be seen in the visual displays of many DVD-Audio players. It is stating that the disc was made with PCM digital audio and was “packed” (compressed) with Meridian Lossless Packing. (See MERIDIAN LOSSLESS PACKING.)
PAD: (See ATTENUATION PAD.)
PAL: Acronym for Phased Alternate Line. PAL is the broadcasting standard used primarily in Europe and Australia, as well as some Latin American and Asian countries. It has more lines on the TV screen than the format used in America, called NTSC (National Television Standards Committee). And therefore separate versions of all video products must be done for release overseas. PAL specifies 768 pixels/line, 576 lines/screen and 25 frames/sec.
PALM TOP: See PERSONAL DIGITAL ASSISTANT.
PANAVISION: The name of a company that manufactures high quality motion picture film cameras and camera equipment for the professional film industry. Panavision has teamed up with Sony to produce the CineAlta 24 frames per second progressive scan high definition video camera system. (More data at 24p.)
PANCAKE: Slang for a large reel of audio tape, wound without the use of tape reel flanges (on an open hub). The pancake may be blank tape or it may have recorded material.
PANCHROMATIC: The prefix “pan-” means “all” and the suffix “-chrome” means “colour”. “Panchromatic” film is a type of black and white film that is sensitive to all visible colours of light. Because panchromatic film is sensitive to every one of the basic colours (blue, green and red) it can produce images that have many shading variations, from bright to very dark areas. It records each colour as different shades of grey, as well as recording the very bright and very dark areas of a scene as black and white, thus producing black and white images having natural gradations in greys and shadows, ranging from very dark (black) to very bright (white) and many shades in between. The earlier monochromatic film used for silent motion pictures was sensitive only to the blue light and the later ortho-chromatic film, which became popular in 1918, was sensitive to blue and green colours photographed, but not red. These two older style films resulted in images (for movies or still photographs) that lacked the many variations of greys that naturally exist. The result was a highly contrasted image, meaning the picture produced was mainly all very black and very white, with no in between gradations of greys. The later panchromatic film was first used in 1926. While it was a major breakthrough in producing a much more natural black and white image, panchromatic film was slower (less sensitive to the brightness of light) than ortho-chromatic or monochromatic films and thus the camera aperture (opening) had to be opened wider to photograph a scene. In doing so, the optical downside is that the larger the camera aperture, the less in focus all objects, from far away to close up, are. In other words, the very wide “depth of focus” achieved with monochromatic and ortho-chromatic films is more difficult to achieve with panchromatic. Photographers take these points into consideration when choosing black and white film types to shoot so as to create the look they wish to achieve. (More data at BLACK AND WHITE FILM, MONOCHROMATIC, ORTHO-CHROMATIC, COLOUR FILM.)
PAN FROM FRONT TO BACK: When mixing in surround sound, moving a sound heard in the front, to the rear loudspeakers so it is clearly heard as a relationship between the front and the rear speakers rather than as a relationship between only the front left and front right.
PANNED HARD RIGHT (or LEFT) and-or RIGHT (or LEFT) SURROUND: When mixing, to place a given sound only in the right or left loudspeakers or, when mixing in surround sound, placing a sound entirely to the right or left side of the surround loudspeaker system.
PANNING THROUGH THE CENTRE SPEAKER: Said in regards to mixing in surround sound when a specific sound in the front loudspeakers is panned from left or from the right, but is heard passing through the centre channel speaker when this is done. This is not just panning from the left to the right front channel. It includes hearing the sound, as it does so, moving through the centre loudspeaker as well. The Mixer works to have the sound transfer smoothly across the front three loudspeakers when this effect is desired.
PANEL PRINTER: A film printer in the Gold Film Lab which prints the 16mm film Release Prints. It is called a panel printer because of its basic design - all the mechanisms are on a large panel. The machine is made by the manufacturer to be modular - meaning that it can be reconfigured to do different printing jobs by taking one panel down and putting another type up on the machine’s frame. It is not a wet gate printer - no liquid is used. But the film and the negative do come in contact with each other. The panel printer is manufactured by the BHP Corporation, formerly known as “Bell and Howell Professional”.
PAN POT: An electronic device that distributes one audio signal to two (or more) channels or loudspeakers. The pan pot places the sound left, centre, right of centre, etc. in mixing.
P&G or P&G FADER: Penny and Giles (an English company that makes electronic parts). A high quality volume control (fader) used in audio equipment, especially mixboards.
PAPERY: Descriptive of the sound of a drum, especially a kick drum, which does not have good tonal quality and presence. It sounds like paper was used to stretch across the drum, rather than a drum skin.
PARALLEL CIRCUIT: 1) An electronic circuit flow in which the source of electrical current feeds two or more electrical devices directly. The current in a parallel circuit flows in such a way that it does not go through one device to another such as the case with a “series circuit”, so interruption of current flow in one of the circuit’s components does not stop current flow in another. For example, if you had a string of Christmas tree bulbs wired in parallel, if one bulb burned out the other lights would still glow. (If the bulbs were wired in series, one burning out would stop the current flow to the others on that string.) 2) A method of sending individual bits of digital computer data all at the same time over multiple wires, rather than linearly all on one wire. 3) Typically refers to a “port” (output or input) on a computer used to send or receive several bits in parallel (usually 8-bits). Most printers connect to a parallel port.
PARALLEL DIGITAL: In computers and some computerised audiovisual equipment “parallel digital” refers to digital information which is transmitted and received in several bits and-or bytes at the same time - and over several different wires (all hooked up to the same connector). This is as opposed to a “serial” connection, which only allows the digital information to flow in one single linear stream. Because more bits and bytes are travelling at the same time, the parallel digital system transfers data faster than serial digital. An example of a system that uses parallel digital information are hook ups for computer printers so more data can flow to the printer faster.
PARALLEL INTERFACE: 1) A method of sending individual bits of digital computer data all at the same time over multiple wires, rather than linearly all on one wire. 2) Typically refers to a “port” (output or input) on a computer used to send or receive several bits in parallel (usually 8-bits). Many printers connect to a parallel port. The SCSI interface is an example of a Parallel Interface.
PARAMETRIC EQUALISER: The root word here is, “parameter”, which can be cleared in any good English dictionary. A parametric equaliser has several bands of frequencies, which can be varied in volume. Each band’s control generally allows adjustment of the centre frequency of the band (what frequencies will be predominately affected by the unit), how much the volume of the band gets boosted or cut, and how wide the band is.
PARITY, PARITY BITS: The word “parity” comes from Latin meaning “equal”. Parity means equal as in amount, status or character. In computers, it means the condition of the bits in a byte or word being either even or odd. Also called “error concealment” and “error correction” bits. Most digital equipment puts additional bits called “parity bits” into a digital signal that help a digital device to replace any lost bits of the digital information. Where the digital recording or processing system cannot verify whether the lost bits were 1’s or 0’s it can make a good guess by comparing other known bits that were close in position to the lost bits. The bits are seen to equal (have “parity” with) those bits which are missing. Parity Bits, which allow the system to recognise information bit errors and-or correct them, are recorded along with the actual digital signal information bits.
PARTIAL(S): A term with the same meaning as overtone and undertone. (See HARMONICS, OVERTONE, UNDERTONE.)
PASSIVE, PASSIVE DEVICE: Any audio device that does not have to be plugged into wall outlet electricity or run off of battery power.
PASSIVE CROSSOVER: For most loudspeakers, the audio signal coming from the amplifier is split up into sets of frequencies (one set each for bass, midrange, and highs) before the signal is received by the individual speakers (drivers) within a cabinet. The electronic circuit which routes these sets of frequencies is called a “crossover” because each set of frequencies could be said to be “crossed over” to a specific driver. Usually these crossovers are built into the speaker cabinet. Some crossovers are external to the cabinet. Usually the latter are adjustable so they can be used with various different types of speakers or used by engineers in designing a new speaker system. An external crossover is said to be “active” when it must first be plugged into wall current in order to work. Most crossovers do not require wall power and, in this case, they are called “passive crossovers” as they do not have to be made “active” (by an external electricity source) before they will work.
PASSIVE EQUALISER: See PASSIVE, PASSIVE DEVICE.
PASSIVE PICK-UP: A musical instrument pick-up (such as for a guitar) that requires no external electricity, as from a battery, in order to pick up and create sound from the vibrating string. Pick-ups that do require electricity to work are called “active pick-ups”. Most guitar pick-ups are passive.
PASSIVE RADIATOR: An additional loudspeaker in a cabinet not actually connected to the audio signal, but it moves back and forth due to pressure generated within the cabinet by the other loudspeakers (which are hooked up to the signal) moving. A passive radiator is used to help reproduce the low bass frequencies. It is a speaker that is not connected to an amplifier, but accompanies another speaker of a similar type in the cabinet, which is also called a “drone cone” or “slave cone”.
PASTE: See CUT AND PASTE.
PA SYSTEM: A “Public Address System”. A loudspeaker system used to present live performances or to communicate outdoors or in a school or business building. It is an audio system used to amplify sound so “public” can be “addressed”. Large music shows use very large PA systems and the speakers can be seen on stage or hung from the hall’s ceiling.
1) To route or reroute the signal in an audio system (such as a console) by using short cables with plugs inserted into jacks.
2) The routing or rerouting of the signal accomplished by #1.
3) The sequence of tone generators and electronic circuits that modify sound, as selected in a musical synthesiser, to obtain a particular sound. (Originally synthesisers were built with the various tone generators and electronic circuits on small modules which were interconnected by short patch cords.)
4) The particular sound obtained out of a synthesiser because of #3.
PATCHBAY: In audiovisual studios. Also called jack bay - a strip of female input and output sockets which are connected to the inputs and outputs of various equipment in the system. Different routings can be rapidly created by using patch cords to change how equipment gets hooked up in the system, without having to go to the back of the equipment to make these changes.
PATCH CABLE: See PATCH CORD.
PATCH CORD: A short length of cable, with a plug on each end, used to route signals in a patchbay. Also called a patch cable.
PATCH POINT: One jack in a patch bay.
PAY PER VIEW: To pay to receive and be able to watch a specific TV programme. Normally cable TV and various satellite TV providers are subscribed to monthly. But to receive certain special programmes, one must pay an additional cost. This is done by calling the cable or satellite company, telling them the show you wish to see and giving them a credit card number for payment. The programme is then made able to be received by the consumer’s cable TV receiver or satellite receiver. Such receivers have a transmission coding system which can be used to block or provide any reception or transmission. Famous boxing matches and major movie releases are examples of common “pay per view’ programming.
PC: Abbreviation for Personal Computer, the original term coined by IBM to describe their first personal computers; now used to mean all IBM-compatible personal computers, or any personal computer.
PC CINEMA: Abbreviation for Personal Computer Cinema. (See HOME THEATRE PERSONAL COMPUTER - HTPC.)
PC DVD: Abbreviation for Personal Computer Digital Versatile Disc. The method of playing a DVD with a personal computer. Said of a system that plays a DVD using a personal computer. This is the highest quality method for DVD playback, even though manufacturers of consumer DVD players will not promote such. A personal computer which is outfitted with a DVD drive, a surround sound “sound card” and several other minor items will present a projected image from a DVD which is markedly better than an actual DVD player. The computer is able to output digital signals to a digital video projector and run the video projector at its highest quality ratings because of this fact. The signal is never turned into analogue video - it is always kept digital. The DVD players, on the other hand, convert the digital information of the DVD to various types of video signals and then route that on to one’s TV or video projector. The player’s picture looks more grainy and fuzzy. The computer’s picture is sharper. There are always new computer accessories coming out monthly which are advancing the quality level and ease of playing DVD using a computer.
PCM: An abbreviation for Pulse Code Modulation. This is the type of digital technology used to create the CD’s and other high quality digital recording formats. It uses digital coding of the music based on changes (modulation) of volume. It is also the type used in many professional studio digital recorders and other devices. Conventional PCM is also called “linear PCM”, which means all its digital information travels with the computer data (bits, etc.) all in a single line or row, not packaged or compressed together. PCM is called “Linear PCM” to distinguish it from other types of pulse code modulation. It is referred to as “linear” because linear PCM keeps the groups of digital bits in one straight (“linear”) line as opposed to dividing them up into compressed groups. In a digital audio signal, the “1’s” and “0’s” making up the digital signal need to be counted correctly and processed in the correct groups. If several 1’s and 0’s are sent back-to-back with no reference, the receiver may not be able to distinguish between them and may miscount the number of bits (which would sound terrible) - thus another signal that contains precise timing information has to be sent along with the bits of data so the bits are always counted correctly. In digital audio recording, the most well-known and used method of doing this is “Pulse Code Modulation”. PCM uses a steady signal (pulse) which runs at the sampling frequency (or a multiple) of the A to D converter. The frequency of the pulses remains constant - only the amplitude of the pulses changes. In PCM, the amplitude of each pulse is varied (modulated) by the audio signal along with the samples being recorded. The way the pulses are changed in amplitude (volume) by the audio signal becomes the digital stream of bits (code). Audio is encoded on CDs in the PCM format with a sampling frequency of 44.1 kHz and a 16-bit sampling size. A 16-bit sample size can contain 65,536 possible levels of sound volume which corresponds to a dynamic range of 98 dB. As a comparison, a DVD-Audio can be encoded in PCM with a sampling frequency of up to 192 kHz and a 24-bit sample size, having a dynamic range of 144 dB.
PEAK: A top volume of signal current.
PEAK INDICATOR: A small light mounted on the front panel of a piece of audio equipment that flickers to alert the engineer that a peak in volume is occurring. They can also be mounted on or near a volume meter.
PEAK LIMITER: A piece of electronic audio equipment that holds back peaks in volume so that the sound signal will not go beyond a certain pre-set level. This type of limiter, if set correctly, does not act on the average volume parts of a programme. It holds back or limits only the peaks of volume.
PEAK MANAGEMENT: Said of various digital audio equipment which can keep the peaks (loud portions of the sound) from going over the digital volume limit and distorting.
PEAK HOLD METER: A type of audio volume meter. A “peak hold meter” will display the peak volumes of signal by having its needle (or other visual display) register a peak and then continue to display it for a short time after the sound that caused the peak has passed. For example, if you were listening to a song and a very loud drum beat was struck the peak hold meter would register the peak volume of that drum hit. The meter’s display would then continue to show that hit for a short time. Then it would register the next peak and so on. The volume meters on some equipment are set up so that they have a peak hold display in addition to a non-holding, normal meter display which just moves freely as it registers the signal of the audio programme. Note: A good example of a peak hold meter can be seen on the Nakamichi model 1000 ZXL cassette decks located in any Gold audio mixing studio.
PEAK OUTPUT: Sudden bursts of power are required in response to certain types of sound. Loud drum beats, explosions and percussive piano playing demand a high peak output power from an audio amplifier. Failure to do so causes signal compression, resulting in a squashed, deadened sound.
PEAK-READING METER: A recording-level meter that rises rapidly and declines at a moderate speed so the user can see the level of transient peaks in sound volume.
PEAK TO PEAK VALUE: The difference in amplitude between positive and negative (highest and lowest) peaks in an audio signal.
PEER TO PEER: Abbreviated P2P 1). A type of computer network where there are individual stations, each having their own files that can be shared by anyone else on the network. The term, “peer” is used because each of the individual computer stations have an equal status on the network. Each can stand alone and does not depend on a large central server for its data. A P2P network does not use a server, files are accessed from individual computer drives using a networking software programme. Examples of Peer to Peer networks include the SADiE system in the Audio building and the “Network Neighbourhood” that can be accessed at various places around the base. 2) An interconnection between two persons via the Internet. Note: P2P is also an abbreviation for “person to person”.
“PEER TO PEER SHARING”: A term describing the practice of using an Internet connection to transfer music or other intellectual properties from one person to another.
PENTAGON: Brand name of a cassette duplicating machine. These were faster than real time copiers that used tape already loaded in cassette shells. The Pentagon line was used for a short time at WHQ and here at Gold. It was nowhere near the speed and quality of the current Gauss High Speed Cassette Duplication Line in A.V. Manufacturing.
PENTIUM PROCESSOR: A computer microprocessor (chip) manufactured by the Intel Corporation. Pentium microprocessors are highly regarded for their speed and efficiency.
PENTODE TUBE AMPLIFIER: A tube amplifier is often referred to by the type of tube used in its output stage: triode or pentode. It’s how many electronic contact points (electrodes) are in the vacuum tube. The first electronic amplification device invented in 1907 by Lee de Forest, who called it the “audion”, was the triode type. The triode, simplest of all amplification tubes, is made with three internal elements. There is also the tetrode which has four electrodes.
For more technical information, read on… The triode, simplest of all amplification tubes, is made from three elements, the plate, the control grid and the cathode. A glowing filament heats the cathode, causing electrons to be emitted into an “electron cloud” near its surface. This phenomenon is called “thermionic emission”. The free electrons are attached to the positively charged plate, meaning that an electrical current flows. (Current is the electrical charge in motion.) As long as the cathode is heated and the plate is positively charged with respect to the cathode, current will flow from the cathode to the plate. To control that flow of current and make the tube function as an amplifier, an element called the control grid is positioned between the cathode and plate. The grid is a mesh of wire that produces an electrical field that controls the flow of electrons, yet doesn’t impede them on their way to the plate. The amount of voltage applied to the grid determines how many electrons jump from the cathode to the plate. Consequently, a low-level audio signal applied to the grid modulates a small flow of current at the plate and a high-level signal produces a large flow. A pentode works in exactly the same way, but has two additional control elements, the screen grid and suppressor grid. These affect the electrical fields inside the tube, greatly increasing the tube’s amplification (gain).
USAGE NOTE: Some tube amplifiers let you switch between triode and pentode operation from the same output tube; in triode mode, the screen grid and suppressor grid are disabled. You may choose triode operation for chamber music at low volume, and pentode for louder music that requires more power. The switchable option also lets you select the best output mode for your loudspeakers. High-sensitivity speakers may work just fine when driven by the amplifier in triode mode; lower-sensitivity models may require the higher output power provided by pentode operation. In 1951, David Hafler and Herbert Keroes developed the ultra-linear output stage, a method of connecting a pentode so that it operates more like a triode. Specifically, some of the plate voltage is returned to the pentode’s screen grid. Ultra-linear operation became the dominant circuit topology in tube amplifiers because it offers the output power of pentodes with the distortion characteristics of triodes. Triode amplifiers generally sound the best but aren’t very powerful and are much more expensive per watt of output power than other tube designs. Triode-based amplifiers can be the push-pull variety or the single-ended type. (See PUSH-PULL, SINGLE-ENDED definition 2.)
PERCEPTIBLE: At or above the threshold of audibility of a trained listener.
PERCEPTUAL CODING: (This is an important term to understand, as it directly relates to many forms of digital audio. It is recommended you first read COMPRESSION3 in this glossary.) When it comes to CONSUMER LEVEL digital audio, the subject of perceptual coding must be fully understood, because, aside from CD’s and a very few music DVD’s, all digital audio information is compressed using the perceptual coding. This includes the entire subject of surround sound. It is even used in professional theatre applications. Perceptual Coding is essentially the “tricks” applied to sound to lessen the amount of digital information and storage space it requires. It is how music is put on the Internet, it is how a film’s soundtrack is put on a DVD, it’s how you hear Dolby Surround Sound at the local cinema, and how the audio for many TV programmes is broadcast. It is how these various systems and methods manage to store and-or transmit tremendous amounts of audio information. They just don’t have the storage capabilities or the transmission capability to deal with as much information the full audio requires when recorded digitally. So, the audio must be “compressed to fit.” Only then will it fit completely on a DVD. Only then can one get it onto the Internet. Perceptual coding is a general term for how these various methods work. Perceptual coding enables one to “perceive” all the audio information is playing, when it actually is not. That’s why it is called Perceptual Coding. How does it work? As you know, digital audio information is really a form of computer information - it is a language computers can deal with. Even a CD player is really a type of computer. A “code” is a specific way the digital information is handled and dealt with. Perceptual Coding is a computer code - a programme - which can make “decisions” about sounds. Specifically, it is a computerised circuit in some digital audio equipment - such as an MP3 player or a Sony MiniDisc, or even a DVD player - that decides what to record and playback for the listener and what not. It seeks to examine the music or other audio programme it is sent to decide what part of the sound the listener will probably not miss if they (the sounds) were not recorded and played back. Upon what are these decisions based? Well, the engineers who thought up Perceptual Coding have tried to get their circuit to sort of “think” like the “human ear hears.” For example, if you were listening to a thundering truck going past, you would not particularly hear the wind behind you. Perceptual Coding “thinks” in the same way. If the person is not going to “perceive” the wind, why bother recording it?! If you were to hear two trucks driving by at the same time, they might sound like just one - so why record two of them? The Perceptual Coding process looks at these types of situations and decides to not record what the “human ear will not perceive.” Perceptual Coding uses the phenomenon that some sounds mask other sounds. This is called “Auditory Masking” - a basic principle of Perceptual Coding. By not recording everything present, less overall sound is therefore required to be stored or transmitted. By recording less, the entirety of a film’s soundtrack can be put onto a DVD disc. 80 songs can be stored in a little MP3 player. A whole CD’s worth of music can be put on the Internet for marketing. An entire film can be broadcast on TV with full surround sound audio. Because all the sound will “fit” into these different formats, the sound is said to be “compressed”. It has been packaged into a smaller unit of digital information so that it can be stored, transmitted, etc. by means which could not do so otherwise. There are many different types of audio compression made by different companies, but their methods all work based on the above.
PERF SCREEN, PERFORATED SCREEN: Most movie theatre screens actually have thousands of small holes - perforations - throughout their entire surface. (You don’t see them as you sit at a distance from the screen.) The small perforations are put there because there are loudspeakers behind the screen and these need to be heard by the audience. The holes allow the audio to come through the screen.
PERIOD: (Sometimes abbreviated “T” or “t” for “time”). The period is the exact amount of time it takes to do one complete cycle of action. For example a 1,000 Hz frequency tone makes 1,000 complete cycles of action in each second, which means it completes 1,000 periods in a second. Therefore, the “period” of a 1,000 Hz tone is 1 1,000th of a second. A 100 Hz tone has a period of 1/100th of a second, a 200 Hz tone has a period of 1/200th of a second and so on. Virtually anything that does exact cycles of action can be said to have a period or a periodic function.
PERIPHERAL: Equipment physically independent of, but which may be used with a mixboard, computer or controller.
PERSONAL AUDIO PLAYER or PERSONAL MP3 PLAYER or MP3 PLAYER or DIGITAL AUDIO PLAYER or MP3 DIGITAL AUDIO PLAYER: These are all names for one thing - the small portable players that can download music from the Internet or even record music from one’s CD collection. Some of these personal audio players can also play MP3 recorded CDs. Personal audio players are most often called MP3 players.
PERSONAL DIGITAL ASSISTANT (PDA): This is the name of small palm-held computer devices. They have the ability to hold clips of films and audio and even operate other devices using infra-red signals. Also referred to as “Palm Tops”, as they can virtually fit on top of one’s palm. Brands include PALM, Compaq iPAQ, Hewlett-Packard Jornada, CASIO Cassiopeia, Targus and others.
PERSONAL TV: This is a general term used to describe the television services (Digital TV, Interactive TV, etc.) received by home consumers and the use of Personal Video Recorders.
PERSONAL VIDEO RECORDER (PVR): A computerised video recorder which has many capabilities. While it is a home consumer unit, it uses professional level video electronics to record any number of programmes and then it can be asked to instantly access any programme one wishes to play back, in any order. It can skip past commercials on playback. It will, for example, automatically record all news programmes in a group, enabling all news programmes to be played back uninterrupted by other TV shows - with each news programme indexed and accessible by an on-screen listing. The person viewing may select any given news programme or as many as one wishes, in any order. Some PVR's can record up to 60 hours. And any one of the individual programmes recorded is able to be selected and placed on the TV screen instantly - and the various programmes reviewed in any sequence. The unit is the same size as a normal video deck but it records all the programmes to an internal hard disc - it is a computer. They have various names such as “TIVO”, “REPLAY”, SHOWSTOPPER, etc. Many consumers now have such units. They are hooked up between one’s TV and the source of the TV signal; satellite dish, cable or TV antenna - even Internet data can be recorded, with proper hook-up. (Microsoft’s “UltimateTV service” gives web access right on TV and the ability to record two channels at once.) PVR’s can be upgraded and-or combined with the electronics required to receive Digital TV (DTV) as well as Interactive TV and other features. One such unit has been released - the “Explorer 8000” from Scientific-Atlanta.
Technical note: The PVR uses MPEG 2, the same compression method that is used to enable an entire film to be copied and placed on DVD-Video discs. Newer PVR’s allow reception of Dolby Digital Surround audio.
PERSPECTIVE: 1) In audio, perspective is the spatial characteristics of a sound or sounds within a recording or mix. Each sound within a recording or mix has a location, depth, and spatial qualities in terms of presence and dimension. 2) In photography and drawing.
PGP: See PRETTY GOOD PRIVACY.
PFL: Abbreviation for Pre-Fader Listen. See AFL for definition.
P-FRAME: A “Predictive Frame”. A term used in video when MPEG compression is applied. See MPEG for exact description of a P-Frame.
PHANTOM CENTRE: See PHANTOM IMAGE.
PHANTOM IMAGE: The re-creation by a loudspeaker system of an apparent sound source at a location other than that of the loudspeakers. Some audiophile magazines refer to the “images” of instruments playing over loudspeakers as “phantom images” because the sounds very much appear to not come from the loudspeakers themselves, but from elsewhere than the loudspeakers. Literally, the sound of a singer can come from between the loudspeakers, though there is no loudspeaker there. Thus the singer is said to be a “phantom image.”
PHANTOM POWER: A system used to supply certain types of microphones with electrical power in order for the microphones to operate. The power is supplied over the same wires that are used to connect the sound output of the microphone to the mixboard, hence the term “phantom” as the electricity is there, but it does not affect the sound, even though it is on the very same wire that is carrying the sound. (It’s there, but not really detectable = “phantom.”)
PHANTOM SURROUND, PHANTOM MODE: Home theatre surround sound systems which do not have a dedicated centre channel speaker, but only a left and right speaker, can use a setting on their surround sound receiver called the “Phantom Mode”. This mode takes the centre channel information and places it into the left and right speakers.
PHASE COHERENCE: The relationship and timing of sounds that come from different individual loudspeaker elements (woofers, midrange and tweeters) mounted in different locations in the loudspeaker cabinet. Also said of the relationship between a properly or improperly phase adjusted subwoofer to the rest of the loudspeakers. Loudspeaker systems that are correctly adjusted for their timing relationships can be called “phase coherent”, as their reproduced sounds reach the listener in time (“in phase”) with one another. This improves the clarity of sound.
PHASE DELAY: A phase delay is when one sound signal is shifted in time relative to another. Some audio components can cause a phase delay just due to their design. The sound signal’s phase going into the equipment is changed by its wiring or internal electronics.
PHASE DISTORTION: A type of audible distortion caused by time delay between various parts of the signal. Equalisers can produce this type of distortion if their controls are moved to radical positions (high or low) because the phase of the individual frequencies is drastically changed.
PHASE DITHERING: (See THX PHASE DITHERING.)
PHASE LINEAR: 1) The quality of not having phase shift. To be phase linear, a device may delay a signal but the delay must be even for all frequencies. 2) An older brand of audio amplification, from the 70’s and 80’s. No longer being made.
PHASE LOCK: 1) In the control of tape machines, a method of keeping machines synched together by sensing phase differences in the playback of pilot tones by the two machines and adjustment of speed to eliminate the phase difference. (See PILOT TONE.) This can also be done by listening to one audio programme played back on two different machines. If the machines are very nearly perfectly in time and if the sound from both machines is sent to a loudspeaker, the sound coming out of the loudspeaker will appear to be sort of squashed and tunnelled. This is because the machines are so nearly in perfect time that part of the sound is being cancelled. 2) In synthesisers, the control of one of its tone generators so that it begins its sound in phase with the signal from another tone generator.
PHASE PLUG: This is a small protrusion in the middle of some loudspeakers. It is usually shaped like small pointed dome right in the centre of the loudspeaker cone. It helps the sound, as it radiates outward from the loudspeaker to have all its frequencies aligned and so they leave the loudspeaker more at the same time. (See PHASE.)
PHASER, PHASING, PHASE SHIFTER: An electronic device for creating an effect that makes musical instruments sound like they are slightly “floaty” or “swimming”. The unit takes the instrument’s sound, like an electric guitar, and splits the signal into two parts. One of the two parts is left alone. The other is altered slightly as to its phase (timing) in relationship to the first part. (See PHASE.) Blending the two parts back together, gives a pulsing effect to the sound.
PHASE REVERSER: A circuit which intentionally shifts the relationship between two signals to put them 180 degrees out of phase with each other (or, if they are out of phase to start with, to bring them in-phase). This can be in the form of a plug-in adapter. Some mixboards have this as a switch on each channel.
PHASE-SHIFTLESS EQ and PROCESSING: This is a method of digital equalisation and other types of audio mixing processing equipment. (See FAST FOURIER TRANSFORM.)
PHILA: An abbreviation for Point of Deployment-Host Interface License Agreement. (See POINT OF DEPLOYMENT.)
PHILIPS: An audiovisual electronics company that makes home consumer equipment of all types. It also has a large professional division for video post production. Philips works very closely with Sony. Together they introduced the CD and a number of other major electronics breakthroughs including newer types of video cameras. Additionally, Phillips makes a popular High Definition telecine machine.
PHON: A unit of apparent loudness of a sound. Phon means “voice.” This is a subjective unit based on the judgment of how loud something is. It is based on how loud a sound is to a group of people, and therefore isn’t of much use as a precise measurement unit.
PHONE JACK: Also called a “quarter-inch jack”. A phone jack is the receptacle for a male phone plug (a quarter inch plug used in electronics). It can be stereo or mono and be mounted on a panel, in equipment, or at the end of an extension cable. The jack in an electric guitar is usually a phone jack.
PHONE LINE (PL): Abbreviated “PL”. 1) A “PL” is an intercom system used by professional audiovisual personnel to speak to each other between rooms or stations during studio production, broadcasts, etc. 2) Phone lines are also used for transferring data over long distances. Computer Internet data uses phone lines. Music and video information can be sent using certain types phone lines.
PHONE PLUG: Also called a6.5mm
PHONO: Abbreviation for “phonograph”. It is a “turntable”. Phono inputs going into audio components to reproduce the phono’s sound, use RCA (brand name) connectors, sometimes called phono plugs.
PHONO CARTRIDGE: The very small part that attaches to a phonograph’s tone arm assembly. The cartridge houses the tiny diamond needle that rides in the grooves of the record.
PHONO CONNECTOR: See PHONO PLUG, CONNECTORS.
PHONO PLUG: Not the same as a “phone plug.” A phono plug is commonly used to connect audio between different pieces of audio electronic equipment. Also called an RCA connector or RCA plug. It’s the type of connector you will find in the back of a Nakamichi cassette deck. They are 2-conductor connectors that have a centre pin about ˝ inch long and 1/8 inch in diameter. Usually the casing for the connector is metal and the casing screws on over the soldered connections. Often the casing is plastic in less expensive versions. This type of connector is very extensively used for both analogue and digital audio signals. A “phono plug” is so called because it was originally used to connect phonograph turntables with a preamplifier. Also called an RCA plug, as it was originated by the RCA Corporation.
PHONO PRE-AMP, PHONO STAGE: A “pre” pre-amplifier specifically and only designed to amplify the signals coming from a phonograph cartridge. The signal from a cartridge is so tiny that it must first be boosted even before it reaches the normal pre-amp for the audio system. This can be a built in circuit inside audio equipment or an extra unit connected to the main pre-amplifier.
PHOTO CD: A compact disc put out by Kodak for the storage of photographs. The Photo CD can be read by a computer with a CD-ROM drive.
PHOTOELECTRIC CELL: A device that generates a small electrical current when it receives light. It is common for small calculators to have photoelectrical cells.
PHOTOGUARD: Brand name of the protective coating (made by the 3M Company) put on film release prints to help prevent damage from dirt and wear.
PHOTORESIST: A light-sensitive chemical coating that is applied to a surface and used to create a specific pattern on that surface when exposed to light. There are two different types of photoresist, one that washes away when exposed to light and the opposite type, which hardens and will not wash away when exposed. The former is used in making Glass Master discs for CD and DVD production and the latter type is used for making printed circuit boards. The chemical coating literally “exposes” (much like photographic film) wherever it is struck by light. An acid bath then removes the coating and etches into the surface wherever the coating does not remain. The acid creates a pattern in the surface. In the case of CDs and DVD’s, the pattern of “pits” is created that is read by a laser in the CD or DVD player. In the case of electronic printed circuit boards, the pattern of metal conductive traces on the board is formed in this manner.
PICKET-FENCING: A tendency for stereo audio volume balance between two loudspeakers to vacillate from left to right as the listener moves laterally with respect to the loudspeakers. (Also called vertical-Venetian-blind effect.)
PICKING: To pluck the strings on a guitar or similar instrument.
PICK-UP: 1) In Audio “pick-up” means to rerecord a short section of a narration, music or other audio recording. “Let’s pick-up the last sentence of this section”.
2) A device for detecting the signals in a guitar or other musical instrument so that its sound can be amplified.
PICK-UP PATTERN: The shape of the area around a microphone in which the mic will best pick up sound. Any sound outside that area (pattern) will not be picked up with clarity and presence.
PICTURE IN PICTURE: A feature on many newer television sets that gives the consumer the ability to watch one programme on TV while having a portion of the screen tuned to an entirely other programme so he or she can see that too.
PICTURE ZOOM: A common feature on DVD Video players which allows the user to zoom in on (enlarge) the centre portion of the DVD’s picture on screen.
PIERCING: Strident sound. Hard on the ears. Screechy. Having sharp, narrow peaks in the response around 3 kHz to 10 kHz.
PIEZO-ELECTRIC SPEAKER: A loudspeaker principle used in some tweeters that employs a ceramic element, which expands or bends when fed a signal voltage. This generates sound. It is used in fairly cheap commercial loudspeakers and less expensive Public Address loudspeaker systems. Also sometimes used in very small loudspeakers, like the type in a cellular phone.
PIG NOSE: A brand of small guitar amplifier that is battery powered. It has a volume control on it below the loudspeaker grill such that it looks like a little pig’s nose.
PILOT TONE: The word “pilot” means to lead, guide or conduct. A tone, in this instance, is a frequency that can be used to guide or conduct other information.
1) The 19 kHz carrier tone used for stereo radio broadcasts. This tone is added to the basic carrier wave of the radio station to separate the left channel from the right channel. Upon receipt of the FM radio programme, the FM radio filters this pilot tone out of the signal so you don’t hear it.
2) A 60 Hz alternating current signal recorded on an audio tape recorder to be used by another machine as a reference so the two machines can run in perfect synch together. The 60 Hz pilot tone is recorded on a separate area of the recording tape so one does not hear it. But the tone’s signal can be sent to other recording machines and the machines can use the tone as a “pilot” to run together at the exact same speed. “Pilot tone” has been superseded for synchronisation by time code.
PINCHED: 1) Sound that is not full bodied. Lacks richness.
2) Audio as heard over loudspeakers where the individual sounds and overall mix lack any size and dimension. Lacks spaciousness.
PINCH ROLLER: On an audio tape recorder. A rubber roller, used to press a tape against the capstan in order to drive the tape across the heads.
PING-PONG: An audio studio recording technique used, during mixing and recording, to transfer two or more tracks of sound on a multi-track tape recorder to other free (blank) tracks to free up those tracks for further recording. The studio is “ping-ponging” the tracks back and forth between tracks on the tape recording machine. Often the sounds are combined, and combined again, using the mixboard, so as to take up fewer tracks.
PINK NOISE: Pink noise was designed and is used for a variety of audio tests. It is a hissing type of noise that contains all audible frequencies from the lowest to the highest. Pink noise comes from - is created from - a similar type of noise called “white noise”. “White noise” is the sound equivalent of “white light” - the light that contains all visible colours. White noise and pink noise both contain all the individual audio frequencies from lowest to highest, but only certain of these frequencies are needed for audio testing - not all the sound frequencies are actually needed. Pink noise test equipment is designed to register only specific individual frequencies. It is important to know that there are more high frequencies registered and displayed by the test equipment than lows. If one were to list out the selected frequencies, there would be more high frequencies than lows on the list. There is a reason why this is. For ease of use, the many individual frequencies of sound are arranged in specific groups. Each group starts with a specific frequency, and ends with another that has 2X the vibrations per second as the starting frequency. Here are some of the frequency groups that are actually used in testing audio equipment: 31.5 - 63, 63 - 125, 125 - 250, 250 - 500, 500 - 1000, 1000 - 2000 (2000 vibrations per second), and so on. The lowest group listed here only contains about 30 individual frequencies, while the highest has 1000. (The full frequency range of pink noise meters is from 25 vibrations per second to 20,000.) There are progressively more individual frequencies within each group as one looks from lowest to highest. White noise and pink noise are composed of these groups. In white noise, each individual frequency has the same exact volume. However, due to the fact that there are more frequencies in each ascending group, each group is bigger than the last and therefore is louder. (Each ascending group is 1˝ times louder than the previous one.) White noise has to be adjusted to make it useful for audio. Pink noise is actually white noise that has been adjusted so all the frequency groups have the same volume one to the next. Thus, the groups in white noise each get louder but the groups in pink noise have been made to all stay the same volume - tailored for use in audio tests. That’s why pink noise displayed on a pink noise meter looks “flat” across the top. USAGE NOTE: Audio technicians and operators know if selected frequencies are okay, then the equipment or procedure they are doing is okay. When a piece of audio equipment is correctly calibrated using pink noise, all the top row of lights on the pink noise meter are even all the way across from the lowest frequencies to the highest. (White noise would appear, on the same meter, to have a diagonal top line of lights - angling upwards from the left to the right of the meter display.) That’s why pink noise is used instead of white - it’s much easier to accurately test audio equipment if the ideal response is simply dead flat across the top of the meter. If they are all the same level across the top, the pink noise is “flat”, meaning “even” (the same). When testing a piece of audio equipment, one sends pink noise into the equipment and looks at it on a test meter before it enters and after it exits the equipment. If the pink noise looks the same exiting the equipment as it did entering the equipment, it can be concluded that the piece of equipment is accurately passing all the frequencies of sound. There is speculation as to why pink noise is called “pink”. It may be because pink is a shade of white and pink noise is white noise that has been slightly altered for use in testing and engineering sound. It could be because white noise is uncomfortable to listen to, whereas pink noise is softer on the ears just as a stark bright white light is harder to look at than a soft pink light. White noise is not commonly used in the testing of audio equipment or in studio work. Pink noise is very commonly used. On our Audio lines, we have a very precise form of pink noise that is generated by a computer chip. Whereas the conventional form of pink noise tends to randomly vary up and down in volume, especially at the lower frequencies, ours doesn’t. The computer chip generates a very stable type of noise that looks very steady on the meter. This enables much more precise calibration of our equipment. Instead of hissing ocean sound, the type of pink noise we use sounds like a huge organ being played with many of its notes going steadily and at once. IMPORTANT: Individual frequencies are also used in testing and calibrating audio equipment. Such are created by a different type of test generator, and measured using a different meter. Both pink noise and individual frequencies have their specific uses in audio.
PINNED THE NEEDLE, PINNING THE NEEDLE: There is a small pin on the right side of a VU meter needle. This pin prevents the needle from travelling too far and damaging itself. When the VU meter needle is bouncing off this pin you could say, “The needle is pinning”.
PIN-OUT, PIN-OUT DIAGRAM: This is an electronics technical term concerning how various wire connectors are attached to wire and cable. A “pin” is a metal part of a connector that connects and passes signal when connected. “Out” refers to the signal flow of current leaving the connector - it is flowing out. Some connectors have many pins, such as those on the back of a computer. To keep them straight when technicians make the connections, they use a diagram. It is a “pin-out diagram”. The term “pin-out” is used to refer to what pin goes to which wire and what signal exactly travels (“out”) on that wire. A “pin-out diagram” is very helpful as one must make sure that both the female and the male parts of the connector are wired the same so the pins will match up.
PINPOINT IMAGING: Sound heard over loudspeakers has “pinpoint imaging” when the many various instruments and-or singer(s) are precisely located in the audio presentation and their “images” are very precise, stable, and focused.
PIPE, PIPES, PIPELINE: Any wire or cable or system of such that can transmit or carry massive amounts of signal and-or digital information.
PIRATE, PIRATE COPY: To illegally make a copy of A.V. material for personal use or duplication.
PITCH RESOLUTION: Most often, said of the clarity and presence of bass frequency notes as heard in music. These notes are some of the hardest for a recording, mix and loudspeaker audio system to present. Often such sounds are muddy or lacking punch and clarity. This hinders precisely hearing the pitch of such sounds. Poor pitch resolution makes all notes sound similar, when actually entirely different notes are being played. Good pitch resolution allows one to hear even subtle changes in the notes and how they are played.
PITS: In manufacturing a compact disc, a laser beam burns microscopic pits on the recording layer of the glass master disc used in CD production. The untouched spaces between such pits are called lands. During the read process, meaning when a CD or DVD is played, the laser light focuses on the spinning track, and since the pits reflect light less intensely, the read head detects the changes in reflectivity, and those changes are processed to produce a binary data stream.
PIVOTED TONE ARM: On phonograph players, the most common type of tone arm. It swivels on a fixed point and as it travels across a record’s surface, it does so at an angle as opposed to a linear tracking tone arm, which travels straight across.
PIXEL: Picture Element. All TVs and video projectors have and use pixels to create their images. A pixel is the basic unit of a display image. The more pixels in an image the better the clarity. There are thousands of pixels and they are so small, one does not see them individually. Pixels are usually rectangular in shape, if one were looked at under a magnifying glass. The word comes from the Greek word “pyx”, meaning “a box” in combination with the word “element”, meaning a basic unit of something - a pixel is simply a box-shaped element. A TV’s screen has lines that create the image one sees. Each line contains a fixed number of pixels. The greater the number of pixels, the higher resolution and finer details in the picture one will see. USAGE NOTE: The most commonly used screens and projectors have their resolution calculated by multiplying the number of horizontal pixels by the number of scanning lines. (The number of vertical scanning lines is actually the number of vertical pixels.) For example, a 480 progressive scan picture is composed of 480 lines x 640 pixels per line for a total of 307,200 pixels. A professional High Definition TV monitor may have as many as two million pixels. Movie film also has pixels - it is calculated by Kodak that there are some 12 million pixels per frame of film.
PJ51: See CONNECTORS, TYPES OF.
PKC: See PUBLIC KEY CRYPTO.
PL1: A Phone Line - a telephone line that links up an intercom system for use by audiovisual professionals so they may communicate during studio production, broadcasting, etc. The intercom system itself is called a “PL” by these staff. At live events “PL” refers to the intercom radios with headsets and also the wire-connected intercom units used by the event crew for their private inter-communications.
PL2: Stands for DOLBY PRO-LOGIC. See DOLBY PRO-LOGIC.
PL II: PL II (2) stands for DOLBY PRO-LOGIC VERSION TWO. See DOLBY PRO-LOGIC.
PLAINTEXT: Computer information (such as an e-mail) that is not encrypted.
PLANAR: A flat (not very thick) speaker that uses a thin Mylar (plastic) film, to vibrate to make its sound.
PLANES: See MIXING PLANES.
PLANT MASTER, CD PLANT MASTER, DVD PLANT MASTER: Companies who specialise in the mass duplication of digital release formats are called “plants” (CD plant, DVD plant, etc.) They have all the specialised equipment required to create these products in high volume. For such a facility, even if eventually done in-house, a specific type of digital master is required that is prepared per exact technical specifications. This master is called a “Plant Master”. The specification requirements for a plant master may vary depending upon the plant, its equipment, and the actual digital format chosen for release (CD, DVD, type of DVD, etc.).
PLASMA, PLASMA SCREEN: Some newer types of computer, video and TV screens use plasma technology to generate their images. The word “plasma” comes from the Greek word meaning “to form, to mould”. Plasma is actually an additional physical state of matter. Matter in the physical universe usually is in the form of solids, liquids or gases. Another form of matter can be created by taking something and putting a very high voltage electrical charge into it. If it is a high enough amount of voltage, it impacts on a substance so much that some of the substance’s electrons are literally forced out of their orbits. These electrons (negatively charged particles) then temporarily exist as themselves outside their atoms. When this is done, because the atoms have lost some of their electrons (negative particles), the atoms themselves become positively charged. This sets up a potential for a flow of energy. This is what plasma is. Usually a gas is the substance used. Video screens can be made using a “plasma” gas. A very high voltage is shot through the gas thus forcing some of the electrons out of the gas atoms. When the voltage is removed, the electrons collapse back into the atoms and, in doing so, give off light. This is repeated rapidly enough in a plasma video screen that the viewer can’t detect the separate cycles of charging of the gas. That is basically how a plasma screen works. It is also the principle at work in fluorescent lights. Plasma technology has been used in developing and manufacturing very high-quality video screens, such as those that are used in the “widescreen” (16:9) video format.
PLASTERY: A hard-sounding reverberation characteristic of a room or hall responding to sound reflecting off its surfaces. Characteristic of bare, plaster-walled rooms. Such a characteristic is called “plastery” as plaster walls, when they reflect sound, have harsh echoes and reverberations.
PLATE: 1) A type of audio mixing reverberation device first marketed by E.M.T. (company name). A large metal sheet (plate) is suspended on spring clips and driven like a speaker cone. The tendency of the device is to continue to vibrate after the input signal is removed. Contact microphones convert the vibration of the plate into an audio signal. 2) An electrode in a vacuum tube that receives the electrons, also called the anode. (See ANODE.)
PLATFORM: A full operating system, database, major piece of software and-or hardware used for specific work applications. Any computer or computerised digital audiovisual equipment using the same “platform” is compatible one with another. For example, one can watch digital TV stations using a “computer platform” (actually receive the channels Internet style and watch the programming on one’s computer screen.) Or one can receive such stations using a digital satellite receiver platform (a receiver box that sits on top of one’s TV set).
PLAYBACK: The reproduction (playing back) of recorded audio or video or film to a listener or viewer by whatever means.
PLAYBACK EQUALISATION: A reduction of the volume of high frequency audio frequencies and increase of the volume of low frequencies during playback of an analogue recorded tape to compensate for the record equalisation. (See RECORD EQUALISATION, PRE-EMPHASIS and POST-EMPHASIS.)
PLAYBACK MACHINE: It is the machine that plays back a video or audio programme when such a programme is being copied, broadcast, mixed, listened to, watched, etc.
PLAYLIST: This is a term used in the SADiE digital audio computer manual. In a computerised audio editing system, such as the SADiE, a “Playlist” is the window on the computer screen that displays the work you are creating. The Playlist acts as a tape machine presenting all of the sounds recorded into the computer for a given audio programme. The computer screen’s cursor acts like the playback head of a tape machine. When you pass the cursor over the Playlist, the sound can be heard as the cursor passes over each section.
PLAYOUT: Used as a noun in audiovisual, a “playout” is any programme that is being played. “The radio station’s playout for Tuesday included all kinds of songs from the 60’s and few commercials.”
PLEXTOR: A brand of CD recorder which accepts computer type hook-ups rather than home audio type recorders and therefore the CD it makes is suitable to be used as a Plant Master which can go to CD duplication houses. It is actually a CD Drive which goes into a computer. (Technical note: The Plextor uses a SCSI hook-up, so the necessary additional computer coding information required by CD mastering plants is provided.)
PLUG: A male connector, usually found at the end of a wire or wire cable, that mates with a corresponding female connector.
PLUG and PLAY: A feature originally developed by the Intel computer company that allows a personal computer to configure itself to automatically work with other computerised gear. A user can “Plug” another device into his PC and “Play” it without having to manually change the settings of his computer. “Plug and Play” is now also seen on advertisements for home consumer audiovisual equipment. It is basically telling the consumer that he or she can just plug it in and it will work in conjunction with other equipment without them having to change their existing equipment’s menu controls or settings.
PLUG-IN ADAPTOR: A small transformer plugged in to the wall to operate small electronic devices. Sometimes called a “wall wart” because they hang off the wall when they are plugged into a wall socket.
PLUG-INS, PLUG INS, SOFTWARE PLUG-INS: These are computer software (usually on a CD-ROM) that are loaded into Digital Audio Workstations (DAW’s). They are actually different types of mixing equipment such as limiters, compressors, reverb units, delay processors, etc. Almost any type of mixing equipment that can be found in a studio now exists in software form for use in computers that process audio signals. They are called “plug- ins” because originally, when computers were first being used for audio processing, the operator could “plug-in” cards that would do various audio functions into the back of the computer. These were “hardware” type plug-ins, and are still sometimes in use. There are now many computers which can process sounds. They can record and even mix sounds. “Plug-ins” are used in such computers. One can purchase all sorts of different plug-ins. Many are designed to exactly replicate famous mixing and recording equipment. Video editing computers also have various types of plug-ins.
+ 4 dBm: (See ZERO VU.)
P-MOUNT: A standardised type of phonograph record cartridge that plugs (mounts) into a specific kind of tone arm; it requires no adjustment or calibration. Why it was called a “P-Mount” is unknown. “P” could simply stand for “phono” or “phonograph”.
POCKET MOVIES: A video clip or film clip that has been downloaded from the Internet or recorded from some other digital source and stored in a small personal computer (called Personal Digital Assistants - Palm Tops, and the like.)
POD: See POINT OF DEPLOYMENT, HOST INTERFACE.
PODIUM: It has become common to refer to the platform and lectern at which a person stands to deliver a speech as a “podium”. In actual fact, a podium is a raised area of a stage or set floor on which such things as lecterns can be placed.
POINT OF DEPLOYMENT, HOST INTERFACE: Abbreviated POD. Point of Deployment is the type of electronics equipment and methods used to prevent unauthorised reception and-or copying of digital cable television broadcasts by consumers who have not subscribed to and paid for their digital cable TV service. The POD-Host Interface System consists of computerised signal scrambling equipment on the premises of the Cable TV company (the “point of deployment”) and a box in the consumer’s home (the “host” box) that receives the signal, unscrambles it, and routes it to the consumer’s set top box. The host box is actually a separate addition to the cable TV receiver box that the home consumer must also have in order to receive cable TV stations. Being the proprietor of both the POD and host units allows the cable company to have its own scrambling code, and thus only consumers who are subscribers to that particular cable TV company - and who have their unscrambling host unit - can view the decoded digital television broadcasts. The encryption device allows cable TV companies to dictate copying and reception terms by imbedding signals in the original broadcast. In other words, digital codes which are broadcast along with the television programme will allow or not allow a home consumer to watch the programme and to make a copy. In order for a consumer to receive and-or copy broadcasts from a cable TV provider that uses POD technology, he or she must be a paid subscriber, have the separate host box and have a set top box that meets the specifications of the POD system. (Meaning that the consumer’s set top box must meet certain quality standards in order to be used with the POD system. And it has to be programmed with the correct digital security code to “talk” with the host unit.) When the scrambled digital TV signal is received by the host, it sends an unscrambled signal to the set top box only if that set top box has a digital code which complements the code in the host unit. Not all DTV broadcasts are scrambled, only the ones specially designated, and, of course, the home consumer having a host device can also receive non-scrambled (“cleartext”) broadcasts as well. The form of copy protection used in the POD system is called DFAST. (See DYNAMIC FEEDBACK ARRANGEMENT SCRAMBLING TECHNIQUE.) The FCC (Federal Communication Commission) has ruled that the security (unscrambling) equipment for decoding scrambled digital cable television broadcasts be separate from the consumer’s cable TV set top box. The ruling is an effort to prevent monopolies on television set top boxes for cable TV. At present, two companies are controlling the scrambling technology (Motorola and Scientific Atlanta) and the FCC ruling is an attempt to give the home consumer an option of purchasing any set top box that meets the requirements of a POD system and not be forced to buy it from only Motorola or Scientific Atlanta. For example, if a consumer has a Sony television, he may wish to purchase a set top box manufactured by Sony. However, in reality, Motorola and Scientific-Atlanta still have a choke-hold on the manufacture and distribution of these decoding boxes, and only one other company - Sony - is also starting to manufacture them. The POD broadcast methods and equipment for cable DTV are covered under PHILA, the Point of Deployment-Host Interface License Agreement. POD technology incorporates a unique form of scrambling called DFAST which was developed by Cable Labs, and relies upon “secret keys” that are stored in both the POD and host devices and are complemented by the keys contained in the set top box.
POINT SOURCE: A design in loudspeaker systems where the individual speaker drivers mounted within a cabinet are positioned so that the sound appears to emanate just from one location in the cabinet - even though there are several individual drivers mounted within the cabinet.
POINT-TO-MULTIPOINT: A single source of information service delivered to many. Said of broadcasting television to many viewers or of a computer or Internet site that supplies information to many users.
POINT-TO-POINT: Any transmission between two locations - point to point, with no vias.
POINT-TO-POINT WIRING: An older style of designing and building electronic circuits before circuit boards were popular. Each small electronic part inside the unit was connected just by hand wiring wire to each. This was the style with which early guitar amplifiers were made and, to this day, some manufacturers and players swear that “point to point wiring” (no use of circuit boards which have metal traces that pass the signal instead of wire) sounds better than amplifiers with circuit boards. The most expensive guitar amps use point to point wiring as it requires considerable labour to build such. Other types of audio amplifiers and equipment use circuit boards or a combination of some point to point wiring and circuit boards. There is no particular proof that point to point sounds any better than a well made circuit board.
POLARITY: The condition of having opposite characteristics, especially in an electrical or magnetic system. There are two terminals in such systems, one positive and one negative. These terminals exhibit polarity, because they are opposites. They are oppositely charged terminals and a flow or potential flow of electrons exists between them. Polarity is easily demonstrated with a magnet. When the poles of a magnet are put together in one direction (plus to minus), they will attract and tend to collapse terminals - unless held apart. They attract and-or flow because polarity exists between terminals. In the opposite direction (plus to plus or minus to minus) the terminals repel - no polarity.
POLAR PATTERN: Note: The definition of “polar” as used in this term is not the same as in the word, “polarity” above. Polar pattern has to do with a visual representation, such as a drawing. The pattern is drawn as a sphere or part of a sphere. 1) For microphones, a graphic display of the directions and area in which the mic will pick up sound. 2) A graphic display of the audio output volume of a microphone in relationship to sound arriving at the mic from different directions. The graph gives the output volume of the microphone and the angle that the sound arrives to the diaphragm’s axis. 3) In speakers, a graphic display of the speaker’s dispersion (how evenly the speaker will cover a listening area at different angles).
POLE PIECES: Iron or other magnetic material which conducts magnetic force to where it can be used in transducers (energy converters) like record heads, playback heads, microphones, etc. “Pole” refers to the north and south poles of a the magnetic tape recorder head.
POLYFUSION: Brand name of an electronic component used for live performances to get rid of microphone feedback automatically. It detects the sound frequencies that are feeding back and, by shifting the pitch, reduces the feedback.
POLYPHONIC: 1) A musical instrument that is able to play more than one note at the same time. (Two or more keys can be played at the same time, like a piano.) An instrument which can play only one is said to be monophonic.
2) Any musical piece with more than one voice or instrument part. (Compare MULTI-TIMBRAL)
POLYPROPYLENE: A synthetic plastic utilised in speaker cones. The material is lightweight and strong, so it makes a good loudspeaker cone.
POLYTIMBRAL: More than one instrument sound (more than one timbre) may be played at the same time. For example, if a synthesiser is playing a grand piano, more than one timbre (characteristic sound) of the piano can be played by the synthesiser simultaneously by a single keyboard key. “Multitimbral” is the more commonly used term for this capability.
1) Short for Popular. Said of any modern music which is upbeat and leans more toward a rock music influence (rather than jazz), but often has much more varied melodic content, instrumentation and rhythmic percussion intertwined with the song’s other musical instrumentation than rock’s traditional blues-based heavy use of guitars.
2) Unwanted sharp noises that can be heard on phonograph records when the needle hits some dirt or a scratch.
3) A noise induced into a microphone and heard over a loudspeaker system if someone breathes into it or bumps it. Also called a “boomp”.
4) Any brief, sharp electrical noise heard when audio equipment is being mishandled or misconnected.
POPCORN NOISE: A slang expression in the film sound industry for the factors (such as popcorn chewing and bags rustling, air conditioning noise and sound from adjacent theatres) in a movie theatre that influence how a movie’s lower volume sounds will be perceived in the theatre environment.
POP FILTER: A windscreen for a microphone to help prevent pops from breaths or wind noise.
PORT: 1) An opening in a loudspeaker enclosure or in a microphone casing, just behind the diaphragm. 2) A jack (connection point) accepting or sending digital data as to and from a computer or digital audiovisual device.
PORTAL: “Portal” comes from the Latin word meaning “a door, gate or entrance”. 1) There are Internet portals, which are the access points to Internet services. Such a portal allows one to have a “door” to a given site, or the entire Internet. Internet service providers provide “portals” so you can log onto the Web. Internet portals include “Web Browsers” (computer programmes that assist in finding Internet sites) such as Microsoft’s Internet Explorer and Netscape’s Navigator. Such programmes are “portals” of entry and interaction on the Net. They have various prompts and instructions to guide and enable the Internet user to fully connect up to any Website.
2) A portal is also any software feature that helps a computer’s operator use the various functions of his computer to its full capabilities. It is a set of instructions and guidance steps that leads one through operating a computer. Examples of portals include the icons visible on a computer screen or those words and symbols on which one can mouse-click to create a file, edit, change typestyles, etc.
PORTED (or VENTED) SPEAKER ENCLOSURE: A type of speaker enclosure that uses a duct or port to improve ability to play low frequency bass notes.
PORTIA: This is a term used in the SADiE digital audio computer manual. “Portia” is a made-up name of an additional plug-in card for SADiE computers that adds video recording, playback and editing to the SADiE system. This card expands the SADiE system so that one can edit both audio and video programmes. The SADiE manual contains detailed instructions on how to set up and use the Portia video card.
POSITIONING OF THE SOUND: Said of the apparent location of a sound in a mix when heard over loudspeakers as opposed to the location of the loudspeaker itself.
POSITIVE (terminal): See ANODE.
POSITIVE FEEDBACK: “Feedback” as used in an electronic circuit is a very different definition of “feedback” than that describing the unwanted howl sometimes created in a live sound system. A “feedback” circuit assists, inside an audio amplifier, to supply amplification. The circuit literally “feeds back” (back into the amplifier) a tiny portion of its output to help increase the amplifier’s volume. “Positive feedback” is a type of circuit used in an audio amplifier to increase the amount of signal. A “negative feedback” circuit is designed to decrease the signal internally inside an amplifier. (Negative feedback circuits are sometimes used as a method of reducing distortion and to make an amplifier operate more stably.)
POST: See POST PRODUCTION.
POST FADER: Post means “after” and a “fader” is a volume control on a mixboard. “Post fader” refers to listening to a sound that has entered the mixboard after it has been adjusted with the volume fader. Each sound has its own fader and that fader can adjust the volume of that sound in the mix. Note that it is possible, by pressing a button on the mixboard, to hear the sound BEFORE it actually arrives to its fader. In other words, it is possible to hear the sound at the exact volume it has entered the mixboard, uninfluenced by the mixboard’s fader. That would be listening to the sound “pre fader”. “Post fader” is any point or stage in the mixboard’s circuitry that the sound may go through after the volume fader has adjusted its loudness.
POST PRODUCTION: Any and all production steps and stages an audiovisual product goes through after its initial shooting or recording. It includes all editing, Film Lab work, recording of additional sounds, mixing, etc. Also called simply “Post”. “The video is in post right now.” Actually includes all marketing too because there can be no packaging or release of a product without it. Post production is any production to get the A.V. product DONE and turned over for distribution as an effective, marketed release.
POTENTIAL: A difference in the number of electrons contained in one terminal of an electrical circuit in comparison to another terminal. Because one terminal has fewer electrons than another, it will tend to draw electrons from the other terminal. This tendency to draw electrons is known as “potential” because there is a potential (possible) path for electrons to flow on. Electrons actually flow from the negative terminal to the positive terminal in electronic circuits. The flow moves from the terminal that has more electrons, named the negative terminal, to the terminal that has less, named the positive terminal.
POTS: Standing for Plain Old Telephone System. “POTS” is a system used for making recordings off of a telephone line. It is “plain old” because it just utilises the existing telephone wires and is a simple device - no computer or complex electronic circuits. The POTS system is a box that you sit next to your telephone. You plug the telephone wire into the box and you can make a recording of the incoming signal.
POWER AMPLIFIER: A device which takes an audio signal and increases its volume (the power or its signal) so that it can be played over loudspeakers. Note that in most cases a preamplifier is needed on the line between the playback device and the power amp. An example of such a line is CD player to preamp to power amp to loudspeakers. The preamp is the first stage of volume increase and the power amp is the second stage, which makes the audio signal strong enough to drive loudspeakers. Headphones usually have their own little power amplifiers built into the playback device - CD player, cassette deck, radio, etc.
POWER AMP: See POWER AMPLIFIER.
POWER OUTPUT: A measurement of the amount (strength, quantity) of signal an audio amplifier has to deliver to loudspeakers. The power output of a loudspeaker amplifier (also called a power amplifier) is usually measured in a unit called watts. A home stereo with a pair of bookshelf sized speakers has on the order of 20 watts of power per channel, while large PA systems such as those used in large halls have several thousand watts per channel.
For more technical data, read on... The continuous power output is a more relevant indicator of an amplifier than its peak output power capacity. Amplifier power output is usually specified relative to an 8 ohm resistive load (which is the amount of resistance imposed by an average loudspeaker). However, most loudspeakers present a load that varies according to audio frequency. Impedances lower than 4 ohms require an amplifier to have considerably more current drive capacity than those above 4 Ohms.
POWER SUPPLY: An electrical circuit that supplies current for an electronic device to operate. Power supplies can be contained within the electronic device, but can also be mounted externally in a separate assembly.
POW-r: This is a term used in the SADiE and ProTools digital audio computer manual. POW-r stands for Psycho-acoustically Optimised Wordlength Reduction. POW-r is a function of the SADiE used when mastering a CD, or any process, where one needs to reduce the bit rate of the original recording. This is also known as “down-converting”. POW-r reduces the bit rate only, not the sampling rate. Sampling rates are reduced using the SADiE Sample Rate Converter. For example, if a music album was originally mixed and recorded at 24 bit, 96 kHz but was to be released on CD, the music would need to be reduced to the CD’s rate of 16 bit, 44.1 kHz. SADiE’s POW-r and SRC functions can be used to perform this reduction. The POW-r process reduces the quantity of audio information with a minimum loss of quality. This enables reducing the size of the original digital audio file and producing a very high quality master for compact disc production. When the process is applied, the computer analyses which parts of the digital audio information to keep and those it can delete. It does this by way of programming based upon the principles of psychoacoustics. (For more information on this process and the psycho-acoustic principles used, see glossary entries PERCEPTUAL CODING, AUDITORY MASKING and CRITICAL BANDS.) The POW-r function in SADiE operates on these principles. It attempts to keep the amount of lost audio information to a minimum when performing its down-conversion processing. POW-r can operate at sample rates between 44.1 kHz and 192 kHz when used with computer hardware that supports those rates.
1) An abbreviation for Peak to Peak Meter, Peak Programme Meter or Peak Position Meter. (See PEAK METER.)
2) Pulse Position Modulation (PPM). A method of recording an audio or video signal onto a digital recorder. A “pulse” is a brief fluctuation, up and down, in the flow of a current. “Position” refers to the physical relationship between each of the pulses and “modulation” simply means “to change or alter the relationship of”. In Pulse Position Modulation, the digital recorder uses a steady stream of pulses to turn the sound or video into digital information. The stream of pulses is really much like a carrier wave, as the pulses “carry” (represent) the audio or video signal. In the case of PPM, the pulses are of constant frequency (meaning the number of times the pulses appear each second remains the same), they have a constant duration (the length of time that each pulse stays at its full volume) and constant amplitude (strength, volume). It is only their timing that changes - i.e. when the pulses occur, the length of time between pulses. These changes (modulations) are what are used to create a digital representation of the signal (a digital signal). The amplitude, duration and frequency of the pulses remain the same, but their timing positions, each relative to each other, “tracks” with the changes present in the audio or picture signals.
PPM METER: (See PEAK METER.)
PPV: See PAY PER VIEW.
PQ: A CD has several digital codes that are part of the overall information on the disc. Included in these are “PQ” codes, which are added to all compact discs. These are what enables a CD player to show (in its display window) the track number, a time readout for each song and the total programme time of the CD. (When you press the skip forward or backward buttons on your CD player, it uses the PQ codes to locate the selected track.) PQ codes are not part of the audio signal, they are located in a separate section of the disc. All the digital information on a CD is broken down into sectors, “A” through “W”. Sectors A - O are the principal code areas, and are for the audio information. P - W are the “sub-code” areas of the disc. Sub-codes P through W contain the additional data used by the CD player. There can even be text and graphics stored in the R - W sectors of the sub-code area. Sub-codes P and Q contain the data comprising the start and end times (minutes and seconds) of a track, an identification number for each track (track 1, 2, 3, 4, etc.), and an ISRC (International Standard Recording Code) number - which helps to track how often a property is played commercially, such as over the radio, so royalties can be collected. USAGE NOTE: Sub-code areas P and Q are where the data for the PQ flags is stored. (A flag is a bit of digital information that is used to indicate something and bring it to the user’s attention. When working with PQ codes, the flags appear as small pennants on the top part of the computer display screen when the PQ function is selected.) These flags indicate the presence of a track on the CD. PQ codes are placed on each LRH lecture for CD release by the Lecture Editors in Audio. (You can see the flags if you open up the PQ bar for the CD version of a lecture in SADiE.)
PQ BURST: (See PQ above.) There is an another type of PQ data called a “PQ Burst.” A “burst” is a signal of very short duration that supplies information. A PQ Burst on a CD contains the table of contents of the disc. It is recorded onto the very beginning of a CD, and its information can be displayed on a CD player equipped to present such information or a computer or television screen.
PQ EDITOR: This term is used in regards to the production of Compact Discs and is also found in the SADiE digital audio computer manual. The “PQ Editor” function in the SADiE computer is used to create the digital master to be used for CD manufacturing. When creating this master, additional data must also be included, such as the disc’s table of contents, start and end points of each edit (song), the track identification number for each song (1, 2, 3, or 4, etc.), the length of each song, etc. The “PQ Editor” is that function on the SADiE system that puts together all this data (called PQ Code). (See PQ for full information.) USAGE NOTE: The PQ editor affects only the PQ data in SADiE, not the audio. It edits just the P and Q sub-codes.
PRE PRE AMP: See PHONO PRE AMP.
PRECEDENCE EFFECT: The tendency for the ears to identify the source of a sound as being in the direction from which it was first heard.
PREDICTIVE FRAME: A “P-Frame”. A term used in video when MPEG compression is applied. (See MPEG for exact description of a P-Frame.)
PRE-FADER: See POST FADER for full definition and comparison.
PRE-MASTERING: When one goes about making a master for CD production or even a one-off CD, there are certain steps done prior called “pre-mastering”. They are the steps that must be done before (pre) making the master (the glass master and stampers used in CD replication). It includes having the audio information to be recorded on the CD all processed by a computer or computerised CD recorder so that the digital information can be transferred directly to the recordable disc. The term “pre-mastering” is mostly used in regard to when a CD master is prepared of an audio release with that master to be sent to a CD duplication plant for mass replication.
PREMIX: (Also sometimes called a sub-mix.) When creating the soundtrack for a film, video or an album, many individual voice, music and sound effects are recorded which are to be a part of the final mix. These take up a great many tape recording machine tracks and mixboard channels. Often this requires an additional mixing step, before the final mix. To try and mix everything at the same time would be very cumbersome, even if one did have two or three mixboards all hooked up together and numerous tape machines as well! Therefore, a “premix” is done, combining the many individual sounds. For example, if a film soundtrack had 12 channels of sound effects, these could be mixed down to 2 channels. The Mixer is then able to do the final mix of the soundtrack having the various elements already mixed and able to be blended right into the overall mix.
PRE PRODUCTION: All the preparatory actions required to plan the shots, procure logistics, etc. for a new film, video or recording. Pre production is really the “primary targets” which must be done before the audiovisual product can be shot or recorded. Pre Production is done once the Future Films Department has researched, scripted and designed a film or video property. It includes all matters related to procuring and preparing talent, scouting locations, camera planning, lighting planning, sound planning, sets construction, props procurement, etc.
PRE-ROLL, POST-ROLL: The amounts of time before (pre) and after (post) the section of tape or computer file on which one wants to perform an edit or recording. This applies to digital audio workstations, tape recording and editing alike. The term “roll” comes from the reels on a tape machine rotating during playback or recording and was carried forward into computerised audio and video. The operator, by using the settings on his machines, determines how much time before and after his edit-record point the machine will play the soundtrack and-or pictures.
PRESENCE: In sound, a quality of realism and aliveness. A sense that one is hearing the sound live, not pre-recorded. Given a quality original recording, presence can be enhanced by an equalisation boost in the upper middle and low high frequency ranges, to give a voice a more close-up effect. Adequate or emphasised response around 5 kHz for most instruments, or around 2 to 5 kHz for kick drum and bass.
PRESENCE BAND: The upper middle range of audio frequencies to which the ear is most sensitive. Typically taken to mean the lower-treble part of the audio spectrum, approximately 1KHz to 5 kHz, which contributes to presence in reproduced sound.
PRESERVE A MIX: To run the mix off - meaning to make a perfect recording of it onto tape or other storage medium so it can be used at some time in the future.
PRESSED DISCS: A term used to distinguish the mass reproduced discs which are replicated by pressing a master disc called a stamper onto the replication disc from the discs that are produced one by one, such as on a CD burner in one’s computer.
PRESSURE EFFECT: In sealed box speaker design, the pressure build-up on one side of the cone which may cause non-linearity and inhibit dynamic range in the low bass.
PRESSURE-GRADIENT MICROPHONE: A microphone whose diaphragm is exposed front and back and diaphragm movement is caused by the pressure difference between its front and back. The back and front pressure difference is caused by the gradient of the sound pressure as a sound moves past the diaphragm. Such a mic is also called a velocity microphone because its output is proportional to the velocity of air particles moving to form the sound. A pressure-gradient microphone has a bi-directional pick-up pattern.
PRESSURE MICROPHONE: A microphone where the diaphragm moves because of the pressure of the sound vibrations hitting one side of the diaphragm working against the normal or controlled air pressure inside the microphone case. Only the front of the diaphragm is exposed to the sound vibrations. The entire air pressure change caused by the sound moves the diaphragm. A pressure microphone has an omni-directional pick-up pattern. Also called a pressure-operated microphone or sealed case microphone.
PRESSURE ZONE: When sound strikes a surface the velocity of the air particles is close to zero and the pressure is relatively high. This high pressure layer is referred to as the pressure zone.
PRESSURE ZONE MICROPHONE: (See PZM.)
PRETTY GOOD PRIVACY (PGP): One of the first and only cryptography software programmes which could avoid government breaking. Developed by Phil Zimmermann and used by many to encrypt computer information being sent on the Internet and other computer networks.
PREVIEW: 1) To play the edit in a digital audio editing system to test it before making a final recording of the edit. 2) In a computer assisted punch-in, to have the computer play over the area while switching the monitoring so that the effect of the punch-in can be heard before it is actually recorded.
PREVIEW MONITOR: A video monitor used to see what is going to be projected or recorded before it gets sent to the video projector and-or tape. It is often used to cue a video tape before playing it out to the audience.
PREVOST: An Italian company that builds film projectors.
PRINTS: Copies of a film or photograph.
PRINT (PRINT TO TAPE): To record. To run the mix or video edit off by making a perfect recording. (Chiefly British.)
PRINTED CIRCUIT BOARD (PCB): An insulated plastic board on which a thin pattern of copper conductors has been made by etching, thus forming conducting paths for electronic components mounted on the board (Abbreviated PCB). Because the etching process is accomplished using a process similar to photography - the developing process used to develop (print) photos, the term printed is used. It is the thin board onto which electronic components - resistors, capacitors and the like - are mounted. PCBs may be single sided or double sided.
PRINT STOCK: The film used in the Film Lab upon which to print films. Just like paper stock is called “stock”, so are the bulk rolls of film to be printed upon to create film copies for orgs. Print stock is blank film which has not been exposed. A film negative is used to transfer an image onto the film using a bright light. The print stock is then exposed with the film image, just like film in a photographic camera when a picture is taken. The print stock is then developed to bring the image to view. Once printed and developed, the print stock is thereafter a PRINT of the film, such as a release print.
PRINT THROUGH: An unwanted phenomenon that occurs with magnetic recording tape. Audio signal is stored on magnetic tape by applying magnetic energy. The magnetic particles on the tape store this signal by retaining the magnetism that was originally applied during the recording process. Ideally, each section of the tape would retain only the magnetic force that was originally applied to it and not pass any of that force onto other sections of the tape. “Print through” is the transferring (printing) of an audio signal from one layer of magnetic tape through to an adjacent layer, as when it is wound onto a reel. It is heard as sort of a “ghost echo” of the sound before and after the section of tape where that sound was recorded. When print through gets severe, the entire audio programme can be quite degraded. This is sometimes a situation with analogue audio tapes. Digital audio tapes do not exhibit the effects of print through. Print through is minimised by recording at the correct volume levels and by correct storage (temperature and humidity) of the tape. It is also minimised by winding tapes “tails out” on their reels.
PRISTINE: Very clean-sounding, very transparent.
PRIVATE KEY: See PUBLIC KEY CRYPTO.
PRO AC: Brand name of a loudspeaker manufacturer.
PRO AUDIO REVIEW MAGAZINE: A magazine which specialises in testing all the latest audio equipment used by professional studios as well as audio engineers doing live shows.
PROCESS (to), PROCESSING: 1) The action of modifying some characteristic of a sound or video signal so as to improve its quality or to create an effect. 2) Video processing can involve altering the size of the picture, creating visual special effects, etc. 3) To develop a negative or film print. 4) To create a surround sound audio presentation by using a surround sound processor.
PROCESSOR: 1) Said of any home consumer or professional level surround sound electronics device that has the various settings and adjustments for the different surround sound formats. It does not have amplification to drive loudspeakers or a radio receiver, so it’s different than an Audio Video Receiver (AVR). 2) The word processor is sometimes used generally to refer to any device, including an AVR, which produces surround sound, though this usage is not technically correct. (Compare AVR, A.V. PROCESSOR, DIGITAL CONTROLLER.) 3) An audio mixing device. A piece of equipment that changes the audio in some way. Examples: reverb, compressor, limiter, delay.
PRODUCTION LINE, PRODUCTION LINE PACKAGE, LINE DOCUMENTATION: An establishment consisting of trained personnel, hats, equipment, procedures, communication lines, flow charts, routing forms, checklists, etc. that correctly produces a high quality product in correct sequence. When a production line is established, all aspects of the line - its personnel, technical specifications, and all procedures used to get a product and to QC that product - are documented in writing and with photos. This information, very clear and easy to read, is contained in DOCUMENTATION BINDERS for the line. These binders are called the “line documentation”.
PRODUCTION MASTER: Abbreviated PM. (See AUDIO PRODUCTION MASTER.)
PRODUCTION MIXER: A Hollywood film industry name for the recordist who records the sound on a film set in the studio or on location. This hat is called a production “Mixer” because, for Hollywood movies, the actors’ voices, when recorded during a shot, are usually sent through a small mixboard and mixed onto one or two tracks of a tape recorder. The production Mixers often use equalisation in an attempt to remove faults from a recording or to add high frequencies to a voice in an effort to make the voices sound clearer. At Gold, we don’t use equalisation on the original set sound recordings - as that is a mixing procedure.
PRODUCTION SOUND: The sound recordings done on the set or on location for a film or video. “There were three tapes of production sound turned over to the Mixer today.”
PRODUCTION TRUCK: See TRUCK.
PROFESSIONAL (a): See the ART SERIES 8 entry in this glossary.
PROFESSIONAL DESK: “Desk” is British for mix board. A “professional desk” is a mix board that is of professional quality, suitable for studio work, as opposed to lower quality models often found in home or project studios.
PROFILE: 1) A visual display of an audio signal shown on a computer screen.
2) Brand name of a digital video and audio hard disc recorder capable of playing back pre-recorded videos and their respective audio tracks.
PROGRAMME: 1) A performance or production, especially on radio or television.
2) That recorded meaningful signal (intended message) which is being played back over a video or audio system.
3) The ordered group of internal directions or set of external commands which direct a computer, digital audiovisual equipment or digital musical instrument to perform the desired tasks.
4) To direct a computer or other digital circuit to perform a specific job or to react in a certain way to a given command.
5) The action of programming - to establish what the commands are to be performed and loading them as instructions into the computer or computerised audiovisual equipment.
PROGRAMME FEED: The word “feed” refers to an audiovisual signal which is being sent (fed) from one location (machine) to another location (machine, TV, etc.). The “programme feed”, at an event, is the combined video and audio signals that enable one to see the complete show over a TV screen. There are individual feeds, called isolated feeds, such as just the picture from one camera with no sound, or just sound from the stage microphone and no picture. These two can be routed upon request, such as during rehearsals.
PROGRAMMABLE: Digital audiovisual equipment or digital musical instruments that contain circuits which can be directed by the user to perform certain tasks upon command.
PROGRAMMED PLAYBACK: The ability to programme a CD or DVD player to play back a disc’s contents in a desired order, different to the order of the programme on the actual disc itself. Often used with multiple CD or DVD changers to have selections from several or more discs play in a desired order. Note: Many players have a “RANDOM” button which, when pushed, will simply play random selections at the machine’s choice. Programmed Playback is actually telling the machine the precise order in which to play desired selections from the discs.
PROGRAMMING: 1) Giving an audiovisual component instructions to carry out. For instance, many compact disc players can be programmed to play selected tracks in any order. Professional video equipment can be programmed to start and stop and do many other functions. 2) The action of setting up a musical synthesiser to play back sounds. Selected sounds are picked and tailored for the desired effect. These sounds are then stored in the synthesiser for easy callback by the musician during a performance or when recording. The sequence the sounds are to play, as well as which specific notes are to be played can all be programmed. It is similar to programming a computer - telling the computer what you want it to do so it will do those actions when called upon to do so.
PROGRAMME MONITOR: A video monitor (TV) to which has been routed the programme (i.e. pictures of the event).
PROGRAMME NUMBER: The number assigned to the pre-recorded selection in a CD or DAT. A song number.
PROGRESSIVE SCANNING (or SCAN), PROGRESSIVE DVD PLAYERS: A TV creates its picture by a beam of light tracing tiny thin lines across the screen very rapidly. The difference between interlaced (“i”) and progressive (“p”) images is how these scan lines are drawn on the screen. An interlaced video image is composed of two parts, called fields. Two fields make up a “frame” of a video picture. A TV (video) picture has 30 frames per second. Again, each frame is made up of two fields in the interlaced scanning method. (That means there are 60 fields per second = 30 frames per second.) Each field is a brief instant of the picture lines being put on the screen so one can see an image. The first interlaced field is only the odd numbered scan lines and the second field is the even numbered scan lines put on the screen. The odd lines are scanned onto the screen first, one after another, in a period of 1/60th of a second. Then the “even lines” are scanned during the next 1/60th of a second, one after another, exactly between where the odd lines were scanned. That’s interlaced scanning - the two types of scan lines are never on the screen at the same time. The “even lines” fall between where the “odd lines” were on the screen. They alternate. This weaving on and off the screen in relationship to each other is called “interlacing”. In interlaced scanning, the full picture is never actually all on the screen at the same time. One can see the picture, but what one is really seeing is only half the potential lines at any one time, every 1/60th of a second. Progressive scanning works differently. A progressive scanned picture has all the lines on the screen at the same time. So, there are more lines of resolution to be seen, thus making the picture image far more sharp and clear. The entirety of a progressive scan picture is scanned onto the screen in one pass of the TV’s light beam from the top to the bottom. In other words, all the even and odd lines are put on the screen, one after the other, “progressively”. As a further note, even though the entire image is being displayed at the same time in progressive scanning, an additional handling is needed. If it were only displayed at the video frame rate of 30 fps, you would definitely see the picture flicker. So, progressive scanning displays the entire picture 60 times per second. Whereas interlaced scanning displays only half of the picture 60 times per second (odd lines and even lines alternating), progressive scanning displays all the lines 60 times per second - twice per video frame.
PROJECT: This is a term used in the SADiE digital audio computer manual. In computerised audio editing systems, a “Project” is a useful way of looking at your work on a job-by-job basis. It is really just a computer file that contains all of the individual parts of the work one does on the SADiE system. A project may have more than one soundtrack, therefore all tracks that comprise the entirety of a completed work are stored in the computer as a Project.
PROJECTION BOOTH: The small room located at the back of a movie theatre, restricted from the audience, which contains the film projector(s) and all theatre electronics.
PROJECTION TV SETS: See REAR PROJECTION TV.
PROJECT STUDIO: A small studio used for audio and video production, or just as a hobby. A project studio can be built at one’s home or in an apartment.
PRO LOGIC: See DOLBY PRO LOGIC.
PROM: (Programmable Read-Only Memory) A memory device whose contents can be electrically programmed (once) by the designer.
PROPORTIONAL-Q EQUALISER (ALSO VARIABLE-Q): A Term applied to graphic and rotary (having knobs that turn instead of volume slides) equalisers describing the fact that the knobs which boost or cut levels also affect how many frequencies are affected (the range of frequencies boosted or reduced). The bandwidth affected varies inversely proportional to the boost (or cut) amounts. Such are very wide for small boost or cut levels and become very narrow for large boost or cut levels.
PROTECTION CODE: A digital code added to music to prevent it from being copied. Any code used to prevent unauthorised copying.
PROTECTION MASTER: A direct copy of the final original master of an edited video. A “Protection Master” is made, in addition to other copies.
PROTECTIVE COATING: Optical discs (CDs and DVD’s) are given a clear plastic or lacquer coat that protects the metallic layer. The coating also prevents air from reaching and oxidising the metallised layer - which would render the disc unreadable. Even with this coating, small scratches, pressure, dirt and other markings can make the disc unreadable. Small scratches in such discs can be polished out with a fine rubbing compound and very soft cloth.
PROTEUS: Brand name of a computer used to do rough demonstrations of songs and music pieces.
PROTOCOL: A “protocol” is a set of rules and agreements that describe and-or instruct how computers interact with other computers or computerised equipment. A protocol enables computers to communicate with each other, transfer files, and operate together.
PROTOOLS: A trade name of Digidesign (company) for a hard-disc digital audio recording system. (See DIGIDESIGN PROTOOLS.)
PROXIMITY EFFECT: When microphones are placed very close to the sound source, such as a singer’s or announcer’s mouth, a boosting of the bass frequencies occurs which is known as the “proximity effect”. You have heard this effect when people put their mouths right up to a microphone and speak. Even a man with a relatively soft or thin voice can sound like he has a very deep voice. Some vocal mic's have a bass “roll off” to compensate for this effect.
Pr Pb: See Y, Pr, Pb.
PSIP: Programme and System Information Protocol. PSIP is a Digital Television (DTV) standard used for sending additional information which is broadcast along with the main programme. PSIP is the standard for how such information is added to a broadcast, and what the content of that information is. Examples include weather reports, stock reports, headline news, home shopping, classified ads and Pay Per View information. This additional information can be seen by the home consumer by selecting it on his or her television remote control. Directed Channel Change (DCC) information, which tailors commercials and news reports for a specific local home consumer audience, is also part of the PSIP standard. (DIRECTED CHANNEL CHANGE is defined separately.)
For more technical information, read on… PSIP is a standard specified by the Advanced Television Systems Committee (ATSC) document A/65. The additional information sent along with the digital broadcast exists within the range of a single television channel’s bandwidth, so will not interfere with adjacent channels. The full text of the ATSC A/65 specification can be found on the ATSC website at www.ATSC.org. Further questions can be handled by contacting the technical director of the ATSC, Jerry Whitaker, via the e-mail address firstname.lastname@example.org.
PUBLIC KEY CRYPTO: A secure method of sending computer information. The US Government has blocked the use of unbreakable encryption by private individuals for years, but recently lost the right to enforce such. Now, complete privacy for the sending of computer information is available. “Public Key Crypto” is what the secure system is called. It works like this. You have two “keys”. The two keys are called a) the PUBLIC KEY and b) the PRIVATE KEY. Anyone can have your PUBLIC KEY. But only you have your PRIVATE KEY. The first, key, the “Public Key”, is widely available to anyone who wishes to send a dispatch or information to you. The second key, the Private Key, only you have. Here is how the system works. Bill writes you a message. He uses your Public Key to encrypt it. Now, not even he can unscramble it. All he can do is send it to you. Only you have your Private Key which will unscramble the message so it is readable. Of course you want to make sure that the message really did come from Bill and not someone else. So, what Bill also did when he wrote the message to you was sign it with his own “digital signature”. To do this, he used a feature provided by his own Private Key. His Private Key, which only he has, enables him, and only him, to put his personal “digital signature” on the message. You then use his Public Key, when you receive his message to verify Bill’s digital signature. (Only Bill’s Public Key will verify that Bill signed the message using Bill’s Private Key.) It’s a two key system for both the sender and receiver. When you want to reply to Bill, you write the reply and then use Bill’s Public Key to scramble the message. Now, not even you can unscramble it. Only Bill can, with his Private Key. You signed the message to Bill using your own Private Key’s digital signature. When Bill gets your message, he first uses your Public Key to verify that it was in fact you who sent him the message. He also uses his own Private Key to unscramble the message to him, which you scrambled using his Public Key. Only he has the Private Key (code) to do so.
PS AUDIO POWER BLOCK: A type of electrical power conditioner made by the PS AUDIO Company. It uses digital circuitry to clean up the power and to enable the user to change the frequency rate of the electricity from its normal 60 cycles to a higher or lower frequency. This can improve (or harm) the quality of audio playback. The Power Block is specifically designed for audio equipment, but is said to be effective on video equipment too, including TVs.
PSEUDO SURROUND: Any one of many artificially created “surround sound” settings found on home consumer audio equipment which attempt, usually through phase shifting and altering of signal timings, to create a “pseudo surround”. The settings may have many different marketing names and be found on everything from ghetto blasters to cheap TV sets. May just be called “surround” but not really be any type of Dolby or DTS surround setting at all.
PSMPS FILMS: See PUBLIC FILMS for full definition and listing.
PS2: Play Station 2. See SONY PLAY STATION 2.
PSU: Power Supply Unit
PSYCHOACOUSTICS: The scientific study of the perception of sound. The study of how things sound to individuals because of how the human hearing mechanism perceives audio. An example of psychoacoustics is the “Cocktail Party Effect”, where a person blocks out of their hearing other people talking in order to hear one person.
PUBLIC FILMS: Following are the Public Scientology Motion Picture Series (PSMPS) films:
LRH PUBLIC FILMS
PSMPS 1: WHAT HAPPENED TO THESE CIVILISATIONS?
PSMPS 2: THE SUMMIT
PSMPS 3: BIRTH
PSMPS 4: RAISING THE BABY
PSMPS 5: EVOLUTION OF A SCIENCE
PSMPS 6: THE ORIGINAL THESIS
PSMPS 7: THE STORY OF BOOK ONE
PSMPS 8: HOW THE ORGANISATIONS CAME ABOUT
PSMPS 9: THE WAY TO HAPPINESS
PSMPS 10: RADIATION
PSMPS 11: BRAINWASHING
PSMPS 12: DRUGS AND THE MIND
PSMPS 13: CLEAR DEFINED AND DESCRIBED
PSMPS 14: THE STORY OF STUDY TECHNOLOGY
PSMPS 15: DUALISM
PSMPS 16: EXTERIORISATION
PSMPS 17: FLAG AND EXTERIORISATION
PSMPS 18: THE BRIDGE AND ORGS
PSMPS 19: THE MARRIED COUPLE
PSMPS 20: THE CHILD
PSMPS 21: WHY FINDING
PSMPS 22: WORK
PSMPS 23: ORGANISING
PSMPS 24: WHERE THE INFORMATION IS
PSMPS 25: FLAG EXECUTIVE BRIEFING COURSE
PSMPS 26: ADVICE TO PERSONS BEING AUDITED
PSMPS 27: THE FIRSTS OF DIANETICS AND SCIENTOLOGY
PSMPS 28: INFLUENCING THE PLANET
PSMPS 29: THE DATA SERIES COURSE
PSMPS 30: INTRODUCTORY AUDITING
PSMPS 31: ASSISTS
PSMPS 32: ACCIDENT PRONENESS
PSMPS 33: THE SURVIVAL RUNDOWN
PSMPS 34: SCIENTOLOGY DRUG RUNDOWN
PSMPS 35: EXPANDED ARC STRAIGHTWIRE
PSMPS 36: EXPANDED LOWER GRADES
PSMPS 37: RESISTIVE CASES
PSMPS 38: HAPPINESS RUNDOWN
PSMPS 39: METHOD ONE WORD CLEARING
PSMPS 40: PTS RUNDOWN
PSMPS 41: INTERIORISATION RUNDOWN
PSMPS 42: NEW ERA DIANETICS DRUG RUNDOWN
PSMPS 43: NEW ERA DIANETICS
PSMPS 44: DIANETICS CLEAR STABILISATION INTENSIVE
PSMPS 45: WHAT IS AUDITING?
PSMPS 46: WHAT IS TRAINING?
PSMPS 47: COURSES
PSMPS 48: STAFF RECRUITMENT
PSMPS 49: OPERATING THETAN
PSMPS 50: SOLO AUDITOR’S COURSE
There are 3 public films not included in the PSMPS series, these are:
TR-1: TR’s IN LIFE
EM-1: MAN THE UNFATHOMABLE
POL: THE PROBLEM OF LIFE
Additional Public Films to be produced are:
SFR: THE SECRET OF FLAG RESULTS
CHCC: THE CASE HE COULDN’T CRACK
PULL INSTRUMENTS SLIGHTLY INTO THE ROOM: To mix sounds in such a way that they have dimensionality out into the listening room itself, but in a way that the sounds remain fully integrated with the overall mix itself.
PULLDOWN: See 3:2 PULLDOWN.
PULSE: A rise and then fall in volume or rhythmic beat - occurs fairly rapidly, with a surge. Said in sound, music and electronics.
PULSE CODE MODULATION (PCM): (See LINEAR PCM.)
PULSE WIDTH: The amount of time that a pulse is at maximum voltage (strength).
PUMPING: 1) Audible fluctuations of background noise as it grows louder and then quieter around a speaker’s voice or instrument’s sound in a recording or mix. 2) Large, random motions of a loudspeaker. 3) Slang - to “pump down a line”: The action of sending an audio or video signal at a healthy volume down a wire or through a chain of electronic equipment so as to mix or create some sort of audiovisual product.
PUNCH or PUNCHY: Said of sound that has very good presence and impact. The recording and mixing quality is excellent and reproduces the instrument, voice or sound effect with realism and clarity.
PUNCH IN: See PRE-ROLL, POST-ROLL for full definition and description of “Punch In.”
Technical note regarding punching in on a digital audio recorder… In digital multi-track recorders, when a punch-in is done, all the sound ON EVERY TRACK throughout the area where the punch-in is done is actually lifted off the tape, stored in memory, and then, when the new part is completed and the “Stop” button pressed, the memory buffer records all tracks, including the new part played or sung back onto the tape. Therefore, if there is a power outage during a punch-in while recording to a digital audio recorder, you run the risk of losing that entire section of the taped sounds, all instruments, all tracks, as the tape was literally being erased during the period the punch-in is being done. Excellent electrical power, preferably with an Uninterrupted Power Supply (UPS), is vital when doing critical professional recordings using digital recorders.
PUNCH-OUT: When doing a recording, “punching-out” stops the recording process started by a “punch-in”, thus preserving the previously recorded track starting at the punch-out point. (See PRE-ROLL, POST-ROLL and PUNCH IN for full details on this process.)
PURE TONE: A “pure tone” is a very exact, precise test tone used in audio studios to test and calibrate equipment. It has no distortions or additives. It is just one single, very exact frequency - one pure frequency.
PURIST: 1) An audiophile who dislikes more modern music as it was not produced simply or of instruments common to orchestras or jazz. 2) A Mixer or Engineer who prefers only mixing very simply without much in the way of more modern effects and processing of the sounds, such as those used for modern pop and rock.
PUSH-PULL CONFIGURATION: 1) In loudspeaker design and manufacture, the technique where one loudspeaker driver is mounted normally - facing outward toward the listener - but a second loudspeaker is mounted so that it faces into the enclosure (speaker cabinet). The listener only sees the first loudspeaker in the cabinet, but there is a second unit right behind it. Both loudspeaker drivers share the same air volume space inside the loudspeaker enclosure (cabinet) and they are wired out of phase with one another. Although electrically out of phase, the drivers are acoustically in-phase - because one is physically mounted backwards from the other. Wiring them out of phase causes their resultant physical motion to be in-phase. This alignment theoretically reduces distortion. 2) A method used in electronic circuits such as those in audio power amplifiers. In a “push-pull configuration” the transistors or vacuum tubes used to amplify an audio signal are connected in such a way that each one is only operating part of the time - changing back and forth very rapidly “on” and “off” as the audio signal to be amplified moves through the circuit. This changing back and forth is the “push-pull” action of the transistor or vacuum tube. The transistors (or tubes, if a tube amp) “share the workload” of handling the audio signal. This configuration tends to increase the amount of power that an amplifier can put out and decrease the amount of distortion of the audio signal. (Compare with SINGLE-ENDED, definition 2.)
PUSH AND PULL OF CONFLICTING FREQUENCIES: Said of loudspeakers in an audio system which, when playing different types of sounds, some of those sounds (frequencies) fight each other to a large degree. Often this is also due to interaction with the room’s acoustical properties. Also, the loudspeakers themselves have certain sonic characteristics and non-linear attributes (inability to produce every frequency of sound evenly) and thus there is unevenness and some degree of fighting of frequencies - some being louder some being produced lower in volume, as well as various phase (time) anomalies as regards to frequency reproduction. This is sometimes referred to as a “push and pull of conflicting frequencies”.
PVR: Abbreviation for Personal Video Recorder. See PERSONAL VIDEO RECORDER.
PWM: (Pulse Width Modulation). A method of recording digital audio by varying (“modulating”) the duration (“width”) of a continuous train of signal “pulses”. The unmodulated signal pulses are at a constant width and amplitude. The audio or video information, when added to the signal, makes the pulses either wider or narrower and this modulation of the pulse widths becomes the digital data stream. (Compare PCM, PPM.)
PZM: Abbreviation for Pressure Zone Microphone. Also called “boundary microphone” or “barrier microphone”. A microphone attached directly onto a flat plate of metal. The plate of metal tends to gather up and reflect sound right into the microphone in addition to the microphone also picking up the sounds in the room directly. For this reason the plate is often called a “pressure zone” as the “pressure” of sound hitting it is used to help the microphone itself pick up the sounds to be recorded. It is called a “barrier” microphone as the flat plate creates a “barrier” that stops and reflects the sound into the microphone. These microphones are often used to record conferences or sounds in a room from a distance. They also work well for some specialised uses such as placing on the inside of a piano.