Glossary
AB stereo Often used to distinguish MS stereo from the convention signal using left and right signals. In the context of microphones it often implies the use of spaced omnidirectional mics rather than a coincident pair.
ADAT A digital multitrack recording system that gives eight tracks on an S-VHS videocassette.
ADPCM (Adaptive Differential Pulse Code Modulation) Conventional Pulse Code Modulation stores the values of a waveform as a series of absolute values. Differential PCM does not do this but instead sends the data as a series of numbers indicating the difference between successive samples.
ADSL (Asymmetric Digital Subscriber Line) Sometimes known as a ‘cable modem’, this is telephone data service where higher data speeds are available. The connection is permanently open. The ‘Asymmetrical’ refers to the fact that the data rate is slower for uploads compared with downloads. The actual data bandwidth that is available is shared between a number of subscribers (contention ratio), and will varying depending on how many are sending or receiving data at any moment.
AES (Audio Engineering Society) Among other things, the AES lays down technical standards. In the context of this book they are best known for a professional standard for conveying digital audio from machine to machine, which has also been adopted by the EBU.
AES/EBU A professional digital audio standard for transferring digital audio between machines. This is balanced and uses XLR connectors. The data format is similar but not identical to S/PDIF, which can see an incoming AES/EBU format signal as copy prohibited.
AIFF Apple AIFF (.AIF, .SND) is Apple’s standard wave file format, and is a good choice for PC/Mac cross-platform compatibility.
ALC (Automatic Level Control) See AVC.
Aliasing Spurious extra frequencies generated as a result of the original audio beating with a frequency generated within the audio processing system (usually the sampling frequency in a digital system). Filters are used on the input to prevent this, but these filters themselves can produce degradation of the signal unless very well designed.
Analogue audio Until digital techniques came along audio was conveyed and recorded by using a property that changes ‘analogously’ to the sound pressure. This property might be electrical voltage, magnetization, or how a groove wiggled. Digital audio replaces this with a series of numbers.
AV (Audio Visual) AV standard hard drives are able to cope with long runs of data (such as a long continuous audio recording) without stopping to recalibrate themselves for temperature variations.
AVC (Automatic Volume Control) Often found as an option on portable recorders, this automatically adjusts the recording level from second to second. This can cause trouble when editing, as the background noise will be going up and down. However, modern AVCs work surprisingly well. The background matching becomes a trivial problem when editing with a PC digital audio editor.
Balanced Normal domestic audio connections are unbalanced; a single wire carries the audio, which is surrounded by a screening braid connected to earth as the return circuit. These circuits are prone to pick-up of unwanted signals as well as high frequency loss when used beyond about 5 metres. Balanced circuits use two wires to carry the audio (still within a screening braid). The audio in the wires is going in opposite directions – as one wire goes positive the other goes negative. Interfering signals induce in the same direction on both wires. The input circuit is designed only to be sensitive to the difference in voltage between the two wires and therefore ignores the induced interference.
Barrier mic Barrier mics are designed to be placed on large, flat surfaces rather than suspended in free air. These are often referred to as PZMs (Pressure Zone Microphones) after a commercial version.
bel See Decibel.
Binaural Current practice is to use this term to mean two channel audio balances intended to be heard on headphones.
BIT (BInary digiT) Digital/PCM systems use pulses that indicate either an ‘ON’ or ‘OFF’ state. Each individual piece of data is known as a bit.
BNC A professional video/digital audio connector with a locking collar.
Byte A group of 8 bits (allegedly a contraction of ‘By Eight’). This is the standard measure of the capacity of digital systems.
Capacitor An electrical component that can store electrical charge, formerly known as a condenser. They consist of two parallel ‘plates’ separated by an insulator. The plates are so close together that when they are charged the positive charge on one plate is attracted to the negative charge on the other. The closer they are together, the greater the attraction. This increases the amount of charge that the device can store. A practical capacitor’s plates are in fact metal foil sheets separated by a sheet of thin insulator rolled into a cylinder, rather like a Swiss roll. This reduces their size and gives them a cylindrical appearance. A specially constructed capacitor forms the basis of electrostatic microphones.
Cardioid (heart-shaped) The most common of microphone directivity shapes. (See page 30.)
CD (Compact Disc) When used without qualification this is taken to mean a standard audio CD. Subsequently adopted for data use in computers, this has led to many variants (see below).
CDR (Compact Disc Recordable) A recordable CD that cannot be erased.
CD-ROM (Compact Disc Read Only Memory) A CD containing data rather than audio.
CD-RW (Compact Disc Read-Write) A recordable CD that can be erased. While these discs can be recorded in audio format, most domestic CD players cannot play them.
Chequerboarding A technique for mixing sections of audio or video. (See page 90.)
Cinch plug Another name for phono plug.
Clock All digital systems have a reference clock, which acts rather like the conductor of an orchestra to keep everything in sync. (See Appendix 2.)
Clone In the digital audio context this is used to mean making an exact sample for sample copy. This is not possible with systems like Minidisc, which use lossy compression systems.
Coax, Coaxial plug A generic term for a connection that uses a cable where one or more conductors are surrounded by a wire braid that helps screen out interference. In the UK, this term is most often used for the plug used for television aerials. In the audio context, some companies use this term for a phono plug.
Coincident pair A stereo microphone technique using directional mics placed as close together as possible.
Compact cassette The proper name for the ordinary analogue audio cassette; undoubtedly the most successful audio recording medium ever invented.
Compression: Audio Compressor limiters are the most used effects devices in the studio. They can be thought of as ‘electronic faders’ that are controlled by the level of the audio at their input. (See page 112.)
Compression: Data There are two types of data compression; non-lossy and lossy. Non-lossy compression is the first (and traditional) form of compression, and reduces the data to be stored on a disk or sent via a modem. The best-known format is the Zip format. A Zip file can be uncompressed to recreate the original data without any change or error. Lossy compression is when graphics and audio are often compressed using formats that approximate the data using assumptions about how we see and hear. (See page 181.)
Condenser microphone Condenser is an old term for capacitor.
Cool Edit Pro A commercial audio editing package for Windows, combining both linear and nonlinear editing.
DAC Digital to analogue converter
DAO (Disc At Once) A technique of burning a CD in one go. This has a number of technical advantages, notably giving the ability to control inter-track gaps or even recording audio into those gaps.
DAT (Digital Audio Tape) Originally a generic term for ‘Digital Audio Tape Recorder’. This is now used specifically for a format developed by Sony, and supported by scores of other manufacturers, that has become popular amongst professionals and semiprofessionals alike for mastering digital audio.
Data Plural of ‘datum’. From Latin ‘things given’. The word is often erroneously used as a singular (correct use is ‘The data are’ rather than ‘The data is’).
DAW (Digital Audio Workstation) A dedicated computer audio editor with specialized controls and software.
dB Decibel
dBA Decibels are used widely in the field of acoustics, audio and video. Subtly different scales are used, and the different types of decibel are indicated by a suffix. The dBA is used in the field of acoustic measurement.
dbx A commercial company that is best known for developing a popular analogue noise-reduction system.
DC Offset Poor analogue to digital converters can have a DC offset that ‘pushes’ the audio away from being centred on zero volts towards either the positive or negative. This is a major cause of clicks on edits. (See section 6.3, Figure 6.4.)
Decibel One-tenth of a bel. This is the normal way of measuring audio. It is a logarithmic system using a standard reference level, and values are expressed as a ratio of a standard level. The bel itself is too large a unit to be convenient for audio. The Richter units used for measuring earthquakes are identical to bels, but with a rather louder reference level! (See page 5.)
Delta modulation A technique where the difference between samples is sent instead of the absolute values usually sent by PCM.
Digital audio Sound pressure level variations are represented by a stream of numbers corresponding to pulses.
Digital audio workstation A dedicated computer audio editor with specialized controls and software.
Digital Versatile Disc (DVD) This is the likely successor to the compact disc. It uses similar technology but takes advantage of the technical developments since the CD was introduced. Recordings are made at a much higher density – eight times greater than CD. Additionally, the DVD is double-sided and also each side can be made up of two layers. This gives massive data capacity, enough for full-length films with 5.1 channel audio. The ‘.1’ is a (not very good) engineering joke – there are in fact six channels of audio, but the sixth channel is a low bandwidth one used for low frequency effects.
DIN (Deutsche Industrie-Norm) German industrial standard. This includes the audio/MIDI/computer DIN plug, which is a standard-sized case and connector containing a number of pins. The most common type met in the audio context is the five-pin 180°.
Disc, Disk A convention has grown up where disc-based media using a magnetic medium are spelt as ‘disk’. Optical recordings like CD and Minidisc, as well as gramophone records, remain spelt as ‘disc’.
Dither A low-level signal, usually random noise, which is added to the analogue signal before conversion to digital. Its effect is to reduce the distortion caused by quantization.
Dolby Dr Ray Milton Dolby, possibly the most influential individual in audio. His company, Dolby Laboratories, began by making audio noise reduction systems. The first, a professional system, became known as Dolby A-type. A simplified system, called Dolby B-type, revolutionized the compact cassette medium for consumers. Dolby C-type gives about 20 dB noise reduction compared with the B-type system’s 10 dB, albeit at the cost of poorer compatibility when played on machines without decoding. Dolby SR (Spectral Recording) is an enhanced professional system that can give better than 16-bit digital performance from analogue tape. Dolby S is a powerful compact cassette system based on a simplified version of SR. As other companies have to obtain a Dolby trademark, the company has become the effective setter of standards for cassette machines, as minimum audio performance is set by Dolby Laboratories to allow their systems to be used.
Dolby Digital Started in the cinema industry, this is the digital multi-channel sound format most widely used on DVD and with digital television.
Dolby Stereo Dolby Laboratories devised a system for putting stereo onto optical release prints in the cinema. This was combined with a phase coding system that allows surround information to be heard. The Left total and Right total channels can be decoded to give Left, Centre, Right and Rear loudspeaker information. In the early 1990s the term ‘Stereo’ was dropped, and the analogue film format is now simply referred to as ‘Dolby’.
Dolby Surround The domestic version of Dolby stereo, as found on video cassettes, CDs, TV broadcasts and video games.
Drop in Switching from play to record while running to make an electronic edit.
Drop out (1) A momentary loss of sensitivity in an analogue recording medium. Digital systems can correct or conceal errors resulting from drop outs in the medium. However, if they fail you will hear a mute instead. (2) Switching from record to playback to end a drop in.
DTMF (Dual Tone Multi-Frequency) These are the tones that modern phones make when dialling. They are used to code the digits 0–9 as well as the special system codes of ‘*’ and ‘ ‘. Four extra codes are also available, known as ‘A’, ‘B’, ‘C’ and ‘D’. The sixteen possible combinations are achieved by sending two frequencies (hence ‘dual tone’) out of a possible selection of a total of eight.
DVD Digital Versatile Disc
Dynamic microphone An alternative word for a moving-coil microphone.
Dynamic range In audio systems, the dynamic range available is determined by the number of bits used to measure each sample. In theory, for every bit extra another 6 dB of signal-to-noise ratio is gained.
EBU (European Broadcasting Union) A trade association for European broadcasters, which also sets technical standards.
Echo Although this is often used interchangeably with the term reverberation (or ‘reverb’), they are technically different. Echo is where you can distinguish individual reflections (Echo … Echo … Echo … Echo) while reverberation is where there are so many reflections that they merge into one continuous sound. (See page 116.)
Edit Decision List (EDL) Used in a non-linear editing process, where the audio files are not altered. Instead a list of instructions (the Edit Decision List) as to what section to play when, at what level, etc. is created, which causes the hard disk to skip around and produce apparently continuous audio.
EDL Edit Decision List
EIDE (Enhanced Integrated Drive Electronics) The most widely used (and hence cheapest) form of hard drive. Most PC motherboards are equipped to handle four drives. The usual alternative is SCSI.
Electret A form of capacitor that remains charged permanently. This means that when constructed as a microphone, it does not need a polarizing voltage. Typically, a simple 1.5-V AA battery is used to power the built-in amplifier.
Electromagnetic Describes devices where magnetism is used to create electricity or electricity is used to create magnetism. Within audio, a moving-coil (dynamic) mic is used to create electricity (the audio signal) by the diaphragm pushing and pulling a coil of wire between the poles of a magnet.
Electrostatic Electrostatic microphones use a diaphragm that is one of the plates of a capacitor held charged by a polarizing voltage. (See page 34.)
EQ Pronounced ‘Eee’ ‘Cue’. A widely used abbreviation for ‘equalizer’, a term for devices like tone controls that modify the frequency response of an audio system. Such devices were originally used by engineers actually to equalize or correct audio deficiencies in land lines and recording systems. They were then borrowed by studio operators to improve their recording mix. Nowadays equalizers are designed specifically for studio use.
Error concealment A technique where errors can be detected but not corrected. Instead they are concealed, often by replacing the sample with an average of the samples either side. This is called interpolation (see below).
Error correction As digital audio is a series of numbers, extra numbers can be added having been generated by various mathematical means. At the receiving end, these numbers can be generated again from the incoming data. If they are different from the extra numbers sent, then error has been detected. With suitable maths, the errors can often be corrected. Because the binary nature of the signal represents only ‘0’ or ‘1’, it is clear that if the incoming value is established as being wrong, then the correct value must be the only other value. Interpolation: a technique where when an error is detected a value between the preceding and following value is substituted, whereas full error correction actually reconstitutes the data. Interleaving: errors can be made easier to correct by interleaving the data so that they are physically spread out on the medium so that a single drop out in the medium does not produce a single burst of errors.
fff ‘f’ is a music term for loud (Italian: forte); the degree of loudness is indicated by the number of ‘f’s, thus fff is very loud.
FFT (Fast Fourier Transform) A mathematical way of defining a filter.
Figure of eight Term used to describe a microphone that is sensitive at the front and back but dead at the sides.
Firewire A standard way of connecting apparatus to a computer that is supported by both PCs and Apple Mac computers. The devices are ‘daisy-chained’ together and can be connected or disconnected without having to reboot the computer. This is faster, although presently less common, than USB.
Flanging Phasing with continuously varying delay.
Flutter Rapid variation of pitch, often caused by a dirty or damaged capstan pulley on an analogue tape machine. A digital recording will be free from this fault.
Flutter echo Term used by those who tend to use the terms ‘echo’ and ‘reverb’ interchangeably, to show that they are really talking about echo.
FM (Frequency Modulation) A way of sending data or audio using a carrier frequency that is varied in pitch. This is used by FM radio, VHS video cassette, hi-fi sound, many hard disks, etc.
FX A widely used abbreviation for ‘effects’.
Gain Another word for amplification.
Giga 1000 million – hence 1 GigaHertz = 1 000 000 000 Hertz = 1 GHz.
Glitch A discontinuity in sound, due to data errors.
Gun Mic A generic term for very directional mics that use a long tube and phase cancellation techniques. Also known as shotgun or rifle mics. Because they are very sensitive to wind noise they are usually concealed in long, furry, sausage-like windshields.
Hexadecimal A numbering system based on the number 16 instead of 10. The characters 0–9 and A–F are used – 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 11, 12 etc. It is a convenient notation for binary numbers as used by computers and for MIDI. FD is easier for a person to distinguish from FB than 11111101 from 11111011.
Hypercardioid A microphone that has a slightly narrower front pick-up compared with a cardioid. The penalty is that there is a reduced sensitivity lobe at the back, giving a dead angle a few degrees to the side of this.
IDE (Integrated Drive Electronics) A way of connecting hard drives to personal computers. It is very cheap and has become very popular, and hence even cheaper. Although the technology has much improved it is regarded by many as inferior to SCSI, as it uses the computer’s processor and slows down programs that are being run at the time. It has been said that IDE works in a way analogous to arriving at a shop counter, asking for an item and saying ‘I’ll wait’, whereas SCSI allows you to go away and do something else because it will ‘deliver’.
Image The perceived location of a single source within the sound stage. The image may be narrow (panned mono) or wide (string section). It may be precise or blurred.
Interleaving Error correction technique (see Error correction above).
Interpolation Error concealment technique (see Error correction above).
ips Inches per second.
ISDN (Integrated Services Digital Network) Sometimes ironically referred to as the ‘It Sometimes Doesn’t Network’, this gives you a direct digital connection to the phone network. There are various audio coders that allow good quality down what is effectively a telephone line. Different organizations have standardized on different systems, and some manufacturers’ gear is not fully compatible.
Kilo (K) The word kilo when used in the context of digital systems usually means 1024, not 1000. This represents the maximum value of a 10-bit word, i.e. 2 to the power of 10. This is not cussedness, but is used because it represents a very convenient unit. So the term 64K will mean 65 536. Some publications use the abbreviation ‘K’ to mean 1024 and ‘k’ to mean 1000.
Limiting Compression of greater than 10 : 1.
Line in An input to be fed by amplified audio rather than a microphone.
Line level Domestic outputs tend to be –8 dB, with professional outputs being +4 dB. 0 dB is 0.775 volts. This strange value dates from telephone technology, where 0.775 volts gave 1 milliwatt into a 600-ohm circuit.
Line out Amplified output of a device.
Linear editor An editor where the audio files themselves are altered by the editing process.
Lossy/non-lossy See Compression: Data above.
LP (Long Play) Usually used to refer to 12-inch gramophone records. However, video cassettes, DAT and Minidiscs have a long play mode.
Mastering The general term for transferring studio material to a final stereo ‘master’, which will be used to generate the copies sold to the public.
Mega 1 million, hence 1 megahertz = 1 000 000 Hertz = 1 MHz (note upper case ‘M’; lower case ‘m’ means milli = 1/1000th when used as a prefix).
Mic Preferred British abbreviation of the word microphone.
Micro One millionth, hence 1 microsecond (1 μs). Used colloquially to mean small computer.
MIDI (Musical Instrument Digital Interface) A standard system for communicating performance information between synthesizers and computers.
Milli One thousandth, hence 1 millimetre = 1 thousandth of a metre (1 mm).
Monaural Sometimes used to mean monophonic, but really means listening with one ear!
Monitoring speaker Monitoring speakers are designed to be analytical and reveal blemishes so that they can be corrected. As a generalization, hi-fi loudspeakers make the best of what is available.
Mono Contraction of monophonic; also contraction of monochrome (i.e. black and white pictures).
Monophonic Usually contracted to ‘mono’, this is conventionally derived from the stereo signal by a simple mix of left and right channels. Beware of some portable tape machines that have a switch labelled mono. This often means that only one input is fed to both legs of the recording, not that the two inputs are mixed and fed to both legs. It is very easy to end up with an interview tape that only has questions on it if a reporter is not aware of this.
Moving coil The most common type of microphone and loudspeaker. A coil of wire attached to a diaphragm is suspended in a magnetic field. If the coil is moved by pressure on the diaphragm, a small voltage is generated. If a current is passed through the coil, the diaphragm will be moved.
MPEG (Motion Picture Experts Group) MPEG is a series of lossy compression systems for audio and video.
MS (Middle-Side) A stereo technique where instead of the left and right information being used for the two audio channels, the middle and side are used. The middle signal corresponds to the mono signal. The side signal corresponds to the amount of ‘stereo-ness’. It is zero for centre signals and at a maximum for sounds coming from the extreme left or right.
Multiplex Generally any method of carrying several signals (e.g. stereo left and right) on a common circuit. Digital radio and television are broadcast using multiplexes that carry a number of channels; how many depends on the quality required.
Nano 1 thousand millionth, hence 1 nanosecond (1 ns).
NICAM (Near Instantaneously Companded Audio Multiplex) Digital system used in the UK to add stereo sound to television broadcasts.
Noise reduction Analogue recordings are often made using noise-reduction systems like Dolby and dbx. They boost the signal on record and apply a correction to this on playback. In the process, noise and hiss are correspondingly reduced. In the digital editor context, noise reduction usually refers to various software solutions that remove clicks, hiss or noise from an existing recording – usually a transfer from an analogue original.
Non-linear editor An editor that does not alter the original audio files. Instead it uses some form of edit decision list to instruct the computer to jump around the hard disk, reproducing and mixing audio as required.
NTSC (National Television System Committee) American colour television system.
Nyquist limit This is named after Harry Nyquist, the Bell Telephone Laboratories’ theoretician who first enunciated the principle that you have to sample at a frequency at least twice that of the highest you intend to transmit.
Omnidirectional Omnidirectional microphones are equally sensitive to audio from any direction.
Out-of-phase If loudspeakers are out-of-phase, this means that their diaphragms move in opposite directions instead of moving in and out together. This has the effect of blurring the sound image and reducing the bass response of a system.
PAL (Phase Alternate Line) Colour television system used by most countries in Europe. This is often used to imply a 25-fps frame rate, although 30-fps versions do exist. Many video cassette machines will output a PAL signal at 30 fps when playing an NTSC tape.
PC Originally a generic term for ‘personal computer’, this has been hijacked to mean a computer based on the original IBM design. While sometimes used to imply using a Microsoft operating system such as Windows (as opposed to Apple Mac), they can also be used for other operating systems such as BeOS, Unix, Linux, etc.
PCM (Pulse Code Modulation) The technique of sending numbers as a series of pulses.
Phantom volts Electrostatic (capacitor or condenser) mics need to be powered to work. Balanced studio mics are often powered by adding the DC voltage (usually 48 V) to the audio wires. Circuitry at each end separates the audio. Although the circuit behaves as if there is an extra wire for the power, it has no physical existence – hence the term phantom.
Phase A measure of the relative delay between two waveforms at the single cycle level. The positive-going zero crossing is described as 0° and the negative-going zero crossing as 180°. Where the difference between the two waveforms is exactly reverse – positive in one is matched by negative in the other – they are said to be 180° out of phase, or just out of phase.
Phasing This is caused by selective cancellation of some frequencies either using a comb filter or, more often, by mixing two nominally identical signals with a short delay between them. In the late 1960s this was a much-loved ‘psychedelic’ sound. If the delay is continuously varied, this is called flanging.
Phono plug The RCA phono plug was originally designed to connect phonograph (gramophone) turntables to amplifiers. This has become a universal way of connecting unbalanced audio (and often video), largely because of the cheapness of the connector.
POTS (Plain Old Telephone System) A general term for ordinary telephone lines, which have limited capabilities compared with specialized systems using newer technology such as ISDN.
ppp ‘p’ is a music term for quiet (Italian: piano); the degree of quietness is indicated by the number of ‘p’s, thus ppp is very quiet.
Pre-emphasis A technique of boosting high frequencies on record or transmission; they are then restored on playback or reception. In the process, any added hiss has top cut applied to it.
Program, programme In this book ‘program’ is used in the context of computers. The British spelling is used in the context of radio and TV programmes.
PZM (Pressure Zone Mic) See Barrier mics.
Quantizing (1) The process of turning an analogue signal (like audio) into numbers. (2) In MIDI sequencers, the automatic moving of notes onto the beat.
Quantizing interval The difference in voltage between quantizing levels.
Quantizing levels The number of possible values into which an analogue signal may be divided or quantized.
RCA plug The RCA company originally devised a plug for connecting phonographs (gramophone turntables) to amplifiers. These plugs became known as phonograph plugs, abbreviated to phono plugs.
Reverb Contraction of ‘reverberation’.
Reverberation The sound made by reflections from a room, or an electrical simulation of this. It differs from echo in that there are so many reflections that individual reflections are not discernible. Reverberation time is measured as the time taken for the reflection level to decrease by 60 dB (RT60).
RIAA (Radio Industries Association of America) A trade association that also sets standards, of which the most often met is the RIAA standard for equalization of long playing gramophone records. When the disc is cut, the high frequencies are boosted and the bass frequencies cut. This is corrected by reversing this on playback.
Ribbon mic A microphone using a corrugated aluminium ribbon as a diaphragm. This is placed within the field of a powerful magnet. Once the standard microphone used by the BBC and other broadcasters, it is capable of extremely good quality, especially on strings. It is advisable to take off your wristwatch before handling one, as the strong magnetic field may stop the watch.
S/PDIF (Sony/Philips Digital Interface) Standardized digital audio connection format using an unbalanced audio connection and phono plugs.
SCMS (Serial Copy Management System) A specification for copy protection flags contained within domestic digital audio connections. While the system allows for no copy inhibition or full copy protection, its default is usually to allow only one digital copy; a SCMS-equipped digital recorder will copy a digital recording set to allow one copy, but the copy it makes will be set to no copying allowed. In practice the system is merely an annoyance for serious recordists working with original material. It can easily be defeated by analogue copying, copying via a computer, or copying via an interface box that allows the resetting of the SCMS flags.
Scrub editing A term now used to describe the traditional way of finding edits on reel-to-reel tape, which involved ‘scrubbing’ the tape back and forth. Many users familiar with tape editing like to have this facility on a digital editor, although this usually soon turns out to be a security blanket.
SCSI (Small Computer Systems Interface) Usually pronounced ‘scuzzy’, this is a way of connecting personal computers. Originally used on Apple Macintosh computers, it is regarded as having many technical advantages over its rival IDE, which is universally used by PCs. However, there is no reason why a PC cannot use SCSI (some PC motherboards have it built in, and others can have a SCSI card fitted). Many people regard the extra expense worth it for the greater reliability it gives to audio recording. Both systems can be used within the same machine. The SCSI interface is also used for other devices like scanners. Seven devices plus the controller can be accommodated by a simple SCSI system, with fifteen devices available on more sophisticated systems.
SECAM (System En Couleur Avec Memoire) French Colour Television system. SECAM VHS tapes will play in monochrome on a PAL video cassette machine.
Serial A term used when data is sent down one wire, one bit at a time.
SMPTE (Society of Motion Picture and Television Engineers) In conversation often referred to as ‘simty’, this body sets standards.
SMPTE/EBU The combined American and European time code standard.
Stereo, stereophony Literally ‘solid sound’, from the Greek. While there is argument over a precise definition, it seems generally to mean using two channels to give a directional effect. Good stereo will do more than this, giving a sense of depth as well as direction.
Table of contents Compact disc and Minidisc use a table of contents to tell them where each track and index begins and ends. If this is lost, then the whole disc becomes unplayable.
TAO (Track At Once) Where a CD is burned one track at a time with one wave file per track. The laser is turned off between tracks.
Time code A code contained within a recording that identifies each part of the tape uniquely in terms of time.
Tinnitus A distressing condition caused by hearing damage, where noises are generated within the ear and are often perceived by the victim to be at a very loud level.
TOSLINK (TOShiba LINK) Optical connector used by many domestic digital audio devices.
Transient A short-lived sound, typically the leading and trailing edges of a note.
USB (Universal Serial Bus) A standard way of connecting apparatus to a computer, which is supported by both PCs and Apple Mac computers. The devices are ‘daisy-chained’ together, and can be connected or disconnected without having to reboot the computer. The presently less common Firewire system is operationally similar but faster.
Variable pattern mic This contains two mic capsules that can be combined in different ways to give a range of directivities. (See page 32.)
Varispeed A control for varying the speed of an analogue recorder, usually on playback. This not only changes the rate but also the pitch. Digital editors usually have software that will allow changes to rate or pitch independently of each other. Small changes of less than 10 per cent are usually very successful, but larger changes can suffer from glitches and artefacts. As a result you are often offered a choice of software methods (algorithms) that have different strengths and weaknesses.
VHS (Victor Home System) Presently the most popular home video tape format. In its NTSC version, this has long play and extended play modes in addition to standard play. PAL systems only have a long play mode. The audio is recorded in two forms. There is a low quality recording on a linear track on the edge of the tape; this is usually mono but some machines provide stereo, sometimes with Dolby noise reduction. Additionally many machines record in stereo, using rotating heads within the video signal. The actual sound uses an FM carrier with a noise reduction, using high frequency pre-emphasis and 3 : 1 compression.
WAV The .WAV format originated from Microsoft as a simple format for storing audio for games, etc. The format has been expanded for professional use adding text fields, etc. If an exported .WAV file begins with a click on another piece of software, then it is possible that this software is not reading the file correctly. There is usually an option to export the files without the text information, which can solve the problem. There is also an ADPCM version of this format giving 4 : 1 lossy compression. This is best regarded as an end-user format.
WMA (Windows Media Audio) A Microsoft rival to MP3 files for streaming over the Internet.
Wow Slow variation of pitch, traditionally caused by an off-centre gramophone record or a slipping capstan pulley on a tape machine. Digital audio systems are entirely free of this, unless it is deliberately introduced as a special effect.
XLR Connector widely used in the professional audio field.
XY stereo In the context of microphones, this is sometimes used to indicate the use of a coincident pair of microphones as opposed to spaced (AB).
Zip drive Proprietary form of removable hard disk cartridge.
Zip format Lossless data compression format much used to reduce the size of program and data files on disk and sent via modems. Unfortunately the assumptions that it makes do not apply to audio, and files can end up larger after Zip compression than they were before.