Audio-Visual Glossary



K or k: 1) Abbreviation for “kilo”, meaning a thousand. 2) Uppercase “K” is also an abbreviation for Kelvin, a unit of measurement. (See Kelvin.)


Kbps: Kilobits per second, also kbits/s, which means thousands (“kilo”) of bits per second, is used mainly in computer communications, for data transmission, receiving and processing rates (speed how much data can be handled per unit of time). Note that Kbps refers to the rate of transmission, reception or processing, not the amount of data stored. Kilobits per second, megabits per second, etc. are used to designate how much data per unit of time can be transmitted, received and processed by computerised equipment.      


KELVIN: “Kelvin” is a unit of temperature measurement named after Sir William Kelvin, a famous 19th century British engineer, physicist and inventor. (One of his many accomplishments included being the electrical engineer in charge of laying the first successful transatlantic cable in 1866.) As a physicist and engineer, Kelvin was very involved in measurements. He introduced several different types of measurement scales. One was a temperature scale that included “absolute zero,” absolute zero being the theoretical temperature where atoms and molecules stop moving because they are so cold. Another type of Kelvin scale, the one most important in the field of audiovisual, precisely measures the “colour temperature” of light. (COLOUR TEMPERATURE is a separate entry.) The Kelvin scale gives a finely graduated scale with which to measure differences in colour. The colour temperature of bright daylight is approximately “5600 Kelvin”, and a common light bulb measures “3200 Kelvin.” Note that Kelvin measurements are not written or stated as “degrees”. They are simply referred to as “Kelvin”, such as “3200 Kelvin”, “5600 Kelvin”, etc. This distinguishes them from other temperature scales.


KEPEX: A model name (Allison Research Company) of a gate which can be controlled by a separate control input (called a “key input”). This input “keys” (starts) the device so as to do its job on the actual sound being processed. In other words, a separate sound is used to tell the gate when to respond to another sound. Used for mixing drums. (See GATE.)


KETTLE DRUMS: Large sets of drums used in orchestral-type music. They are made of brass or copper. Also called Tympani.


KEVLAR: A yellow-coloured woven material, somewhat like woven fibreglass, which is used in bulletproof vests. Kevlar is also used in the audio industry to manufacture some types of loudspeakers because it can be made very stiff and strong, yet lightweight. (A speaker’s material must be stiff, but not heavy so it can then move rapidly to produce accurate sound.)


KEY, KEY CODE, KEYSTREAM: 1) A digital information code embedded within digital communications and audiovisual programmes used to encrypt and decrypt the data when it is transmitted over the Internet and other communication lines such as cable TV, satellite TV, etc. The key prevents unauthorised persons from receiving communication or       audiovisual programmes, such as those who have not paid to receive it, or those who would illegally try to copy the programme. It’s called a

“key” because it is a code used by authorised users to “unlock” the programme so they can hear and/or see it. For example, if you were a valid cable TV subscriber, you would have a receiver box in your home and inside that box is a small computer circuit which will decode the key code. Your next door neighbour, not having such a box, could not receive the programme and even if he tried to build his own box, he would not know the special key code circuit that would “unlock” the programme. 2) To “key” something is to send a signal “telling” it that it is to now perform a function or to act in a certain way. Some mixing equipment is “keyed” by other equipment to tell it how or when to perform its function.


KEY (music definition): 1) Any one of the levers pushed on a piano or similar instrument to produce a note. 2) Since the end of the 16th century, our music has had the basis of established “keys”. A key consists of seven notes that are related to an eighth—the eighth note is actually the “keynote”, which is the root, the basic note for the rest of the seven notes. There are many different keys music can be played in. Every piece of music, or its various individual parts, is played in a “key”. If the keynote is the note “C”, then the music is said to be “in the key of C”. Some different keys can tend to involve different moods or feelings and expressions in music. And some musical instruments are designed to best play in certain keys. A singer’s voice is often better in some keys than others. At times, a song’s key will have to be changed to better suit the singer’s vocal range. Famous classical composers would write pieces in different keys so as to feature instruments in their best key or keys. “That symphony for violin is in the key of D.” There can be variations played within a given key, such as “minor” and “major”. These express different moods.


KEY CODE, EDGE CODE: Also referred to as “edge numbers”. These are inked numbers applied by a film manufacturer to the original camera negative film. Key code numbers are printed outside the sprocket holes on film. They are used as a reference for film footage and also to locate specific film frames. They enable the film’s editor and negative cutter to locate the precise frames upon which they must cut and splice to assemble the film per the approved edit.


KEYED: Said of an electronic circuit or device that is actively in operation. Literally, a circuit that is switched into operation is said to be “keyed”. “Key”, as used here, means an electrical switch used to activate and deactivate a circuit.


KEYNOTE: See KEY (music definition).      


KEYSTONE: Distortion of a projected image (film or video) caused by an incorrect alignment of a projector to the screen. The angle of misalignment causes the image to go out of square. A film projector should always be perfectly aimed, straight at the screen. Video projectors too whenever possible, though these usually have keystone adjustments to compensate for the fact they often have to be located low to the floor or high in the ceiling relative to the screen.



kHz: An abbreviation for thousands of cycles per second. “k” stands for kilo or thousand. “Hz” stands for “Hertz.” (See HERTZ).


KICK DRUM, “the kick”: The large central drum that sits on the floor in front of a drummer and is played by stepping on a foot pedal, attached to which is a movable arm that beats the drum. It “kicks” the drum by the drummer “kicking” the foot pedal. This is one of the main drums worked on hard when recording and mixing to get just right as it principally drives the rhythm and beat of the song.


kilo: Abbreviated k (always lower-case). A prefix signifying thousands.


Kilo: Abbreviated K (always upper-case). A prefix used in computer work to signify multiples of 1024. Meant to distinguish base 2 (binary) from base 10 (decimal) magnitudes. For example, a “16K” memory is actually 16,384 bits (i.e., 16 times 1024).


KILOBYTE: In computer usage, this basic number means 1024 bytes, which is 2 to the tenth power—the base 2 numbering system. It is used to count storage capacity, file lengths, and other byte-related amounts. Today, larger multiples are in everyday use (Megabyte, Gigabyte, Terabyte and so on). It is of note that these units are often wrongly interpreted to mean multiples of 1000 in the decimal system, when they are actually in the binary numbering system.


KILOHERTZ: Thousands of Hertz. This term is usually prefaced by a number, as in 1 kilohertz, meaning one thousand times a second.


KLARK-TEKNIK GRAPHIC EQUALISERS: Klark-Teknik is a company that manufactures professional audio mixing equipment. There are Klark-Teknik graphic equalisers in every mixing studio at Gold. The model numbers include DN-27, DN-30, DN-300 and DN-360.


KNEE: How a compressor or limiter reacts to the input signal around the threshold (the input level where the unit begins to change the volume of the sound signal). It’s called the “knee” because if you graphed the amount of sound volume the limiter or compressor puts out compared to the amount going into it, the graph’s line would resemble a bending knee.


KRELL: A manufacturer of audio electronics equipment, such as amplifiers.


K2 MASTERING: A process for creating glass masters for c.d. duplication developed by JVC (Japanese Victor Corporation). It is highly advanced and takes extreme care to ensure such masters have correct phase, and that distortion of all types is non-existent. It is called “K2”, after the mountain. (K2 is the second highest mountain in the world, and the toughest to climb, even harder then Everest, the highest mountain.)