Glossary - Production Glossary G - S

G

GAIN: The amount by which a circuit amplifies a signal.

GATE(1): An electrical signal that is generated whenever a key is depressed on an electronic keyboard. This is used to trigger envelope generators and other events that need to be synchronised to key action.

GATE(2): An electronic device designed to mute low level signals so as to improve noise performance during pauses in the wanted material.

GENERAL MIDI: An addition to the basic MIDI spec to assure a minimum level of compatibility when playing back GM format song files. The specification covers type and program number of sounds, minimum levels of polyphony and multitimbrality, response to controller information and so on.

GLITCH: Describes an unwanted short term corruption of a signal, or the unexplained, short term malfunction of a piece of equipment. For example, an inexplicable click on a DAT tape would be termed a glitch.

GM RESET: A universal sysex command which activates the General MIDI mode on a GM instrument. The same command also sets all controllers to their default values and switches off any notes still playing by means of an All Notes Off message.

GRAPHIC EQUALISER: An equaliser whereby several narrow segments of the audio spectrum are controlled by individual cur/boost faders. The name comes about because the fader positions provide a graphic representation of the EQ curve.

GROUND: Electrical earth or 0 Volts. In mains wiring, the ground cable is physically connected to the ground via a long conductive metal spike.

GROUND LOOP: Wiring problem where multiple ground connections are causing audible mains hum to be picked up. Also known as earth loops.

GROUP: A collection of signals within a mixer that are mixed, then routed through a separate fader to provide overall control. In a multitrack mixer, several groups are provided to feed the various recorder track inputs.

GROUND LOOP: A condition likely to lead to the circulation of currents in the ground wiring of an audio system. When these currents are induced by the alternating mains supply, hum results.

GS: Roland's own extension to the General MIDI protocol.

H

HARD DISK: High capacity computer storage device based on a rotating rigid disk with a magnetic coating onto which data may be recorded.

HARMONIC: High frequency component of a complex waveform.

HARMONIC DISTORTION: The addition of harmonics that were not present in the original signal.

HEAD: The part of a tape machine or disk drive that reads and/or writes data to and from the storage media.

HEADROOM: The safety margin in dBs between the highest peak signal being passed by a piece of equipment and the absolute maximum level the equipment
can handle.

HIGH PASS FILTER (HPF): A filter which attenuates frequencies below its cutoff frequency.

HISS: Noise caused by random electrical fluctuations.

HUM: Signal contamination caused by the addition of low frequencies, usually related to the mains power frequency.

Hz: Short for Hertz, the unit of frequency.

I

IC: Integrated Circuit.

IMPEDANCE: Can be visualised as the 'AC resistance' of a circuit which contains both resistive and reactive components.

INDUCTOR: Reactive component that presents an increasing impedance with frequency.

INITIALISE: To automatically restore a piece of equipment to its factory default settings.

INSERT POINT: A connector that allows an external processor to be patched into a signal path so that the signal now flows through the external processor.

INSULATOR: Material that does not conduct electricity.

INTERFACE: A device that acts as an intermediary to two or more other pieces of equipment. For example, a MIDI interface enables a computer to communicate with MIDI instruments and keyboards.

INTERMITTENT: Usually describes a fault that only appears occasionally.

INTERMODULATION DISTORTION: A form of distortion that introduces frequencies not present in the original signal. These are invariably based on the sum and difference products of the original frequencies.

I/O: The part of a system that handles inputs and outputs, usually in the digital domain.

IPS: Inches Per Second. Used to describe tape speed.

IRQ: Interrupt Request. Part of the operating system of a computer that allows a connected device to request attention from the processor in order to transfer
data to it or from it.

ISOPROPYL ALCOHOL: Type of alcohol commonly used for cleaning and de-greasing tape machine heads and guides.

J

JACK: Commonly used audio connector. May be mono or stereo.

K

k: Abbreviation for 1000 (kilo). Used as a prefix to other values to indicate magnitude.

kHz: 1000Hz

kOhm: 1000 ohms

L

LED: Light Emitting Diode. A form of solid state lamp.

LCD: Liquid Crystal Display.

LFO: Low Frequency Oscillator, often found in synths or effects using modulation.

LSB: Least Significant Byte. If a piece of data has to be conveyed as two bytes, one byte represents high value numbers and the other low value numbers, much in the same way as tens and units function in the decimal system. The high value, or most significant part of the message is called the Most Significant Byte or MSB.

LIMITER: Device that controls the gain of a signal so as to prevent it from ever exceeding a preset level. A limiter is essentially a fast acting compressor with an infinite compression ratio.

LINEAR: A device where the output is a direct multiple of the input.

LINE LEVEL: A nominal signal level which is around -10dBV for semi-pro equipment and +4dBu for professional equipment.

LOAD: Electrical circuit that draws power from another circuit or power supply. Also describes reading data into a computer.

LOCAL ON/OFF: A function to allow the keyboard and sound generating section of a keyboard synthesizer to be used independently of each other.

LOGIC: Type of electronic circuitry used for processing binary signals comprising two discrete voltage levels.

LOOP: Circuit where the output is connected back to the input.

LOW FREQUENCY OSCILLATOR (LFO): An oscillator used as a modulation source, usually below 20Hz. The most common LFO waveshape is the sine wave, though there is often a choice of sine, square, triangular and sawtooth waveforms.

LOW PASS FILTER (LPF): A filter which attenuates frequencies above its cutoff frequency.

M

mA: milliamp or one thousandth of an amp.

MB: Megabyte. 1,000,000 (one million) bytes of data.

MEG: Abbreviation for 1,000,000.

MDM: Modular Digital Multitrack; a digital recorder that can be used in multiples to provide a greater number of synchronized tracks than a single machine.

MACHINE HEAD: Another way of describing the tuning machines of a guitar.

MEMORY: Computer's RAM memory used to store programs and data. This data is lost when the computer is switched off and so must be stored to disk or other suitable media.

MENU: List of choices presented by a computer program or a device with a display window.

MIC LEVEL: The low level signal generated by a microphone. This must be amplified many times to increase it to line level.

MICROPROCESSOR: Specialised microchip at the heart of a computer. It is here that instructions are read and acted upon.

MIDI: Musical Instrument Digital Interface.

MIDI ANALYSER: Device that gives a visual readout of MIDI activity when connected between two pieces of MIDI equipment.

MTC: MIDI Time Code; a MIDI sync implementation based on SMPTE time code.

MIDI BANK CHANGE: A type of controller message used to select alternate banks of MIDI Programs where access to more than 128 programs is required.

MIDI CONTROLLER: A term used to describe the physical interface by means of which the musician plays the MIDI synthesizer or other sound generator. Examples of controllers are keyboards, drum pads, wind synths and so on.

MIDI CONTROL CHANGE: Also knows as MIDI Controllers or Controller Data, these messages convey positional information relating to performance controls such as wheels, pedals, switches and other devices. This information can be used to control functions such as vibrato depth, brightness, portamento, effects levels, and many other parameters.

(STANDARD) MIDI FILE: A standard file format for storing song data recorded on a MIDI sequencer in such as way as to allow it to be read by other makes or model of MIDI sequencer.

MIDI IMPLEMENTATION CHART: A chart, usually found in MIDI product manuals, which provides information as to which MIDI features are supported. Supported features are marked with a 0 while unsupported feature are marked with a X. Additional information may be provided, such as the exact form of the Bank Change message.

MIDI MERGE: A device or sequencer function that enables two or more streams of MIDI data to be combined.

MIDI MODULE: Sound generating device with no integral keyboard.

MULTITIMBRAL MODULE: MIDI Sound Source capable of producing several different sounds at the same time and controlled on different MIDI channels.

MIDI MODE: MIDI information can be interpreted by the receiving MIDI instrument in a number of ways, the most common being polyphonically on a single MIDI channel (Poly-Omni Off mode). Omni mode enables a MIDI Instrument to play all incoming data regardless of channel.

MIDI NOTE NUMBER: Every key on a MIDI keyboard has its own note number ranging from 0 to 127, where 60 represents middle C. Some systems use C3 as middle C while others use C4.

MIDI NOTE ON: MIDI message sent when note is played (key pressed).

MIDI NOTE OFF: Message sent when key is released.

MIDI OUT: The MIDI connector used to send data from a master device to the MIDI In of a connected slave device.

MIDI PORT: The MIDI connections of a MIDI compatible device. A Multiport, in the context of a MIDI Interface, is a device with multiple MIDI output sockets, each capable of carrying data relating to a different set of 16 MIDI channels. Multiports are the only means of exceeding the limitations imposed by 16 MIDI channels.

MIDI PROGRAM CHANGE: Type of MIDI message used to change sound patches on a remote module or the effects patch on a MIDI effects unit.

MIDI SPLITTER: Alternative term for MIDI Thru box.

MIDI THRU BOX: Device which splits the MIDI Out signal of a master instrument or sequencer to avoid daisy chaining. Powered circuitry is used to 'buffer' the outputs so as to prevent problems when many pieces of equipment are driven from a single MIDI output.

MIDI IN: The socket used to receive information from a master controller or from the MIDI Thru socket of a slave unit.

MIDI OUT: The socket on a master controller or sequencer used to send MIDI information to the slave units.

MIDI SYNC: A description of the synchronisation systems available to MIDI users - MIDI Clock and MIDI Time Code.

MIDI THRU: The socket on a slave unit used to feed the MIDI In socket of the next unit in line.

MIXER: Device for combining two or more audio signals.

MONITOR: A reference loudspeaker used for mixing.

MONITOR: The action of listening to a mix or a specific audio signal.

MONITOR: VDU display for a computer.

MONOPHONIC: One note at a time.

MOTHERBOARD: The main circuit board within a computer into which all the other components plug or connect.

MULTI-SAMPLE: The creation of several samples, each covering a limited musical range, the idea being to produce a more natural range of sounds across the range of the instrument being sampled. For example, a piano may need to be sampled every two or three semitones in order to sound convincing.

MULTI-TIMBRAL: A synthesizer, sampler or module that can play several parts at the same time, each under the control of a different MIDI channel.

MULTITRACK: A recording device capable of recording several 'parallel' parts or tracks which may then be mixed or re-recorded independently.

N

NEAR FIELD: Some people prefer the term 'close field', to describe a loudspeaker system designed to be used close to the listener. The advantage is that the listener hears more of the direct sound from the speakers and less of the reflected sound from the room.

NOISE REDUCTION: System for reducing analogue tape noise or for reducing the level of hiss present in a recording.

NOISE SHAPING: A system for creating digital dither such that any added noise is shifted into those parts of the audio spectrum where the human ear is least sensitive.

NON REGISTERED PARAMETER NUMBER: An addition to the basic MIDI spec that allows Controllers 98 and 99 to be used to control non-standard parameters relating to particular models of synthesizer. This is an alternative to using System Exclusive data to achieve the same ends, though NRPNs tend to be used mainly by Yamaha and Roland instruments.

NON-LINEAR RECORDING: Describes digital recording systems that allow any parts of the recording to be played back in any order with no gaps. Conventional tape is referred to as linear, because the material can only play back in the order in which it was recorded.

NORMALISE: A socket is said to be normalised when it is wired such that the original signal path is maintained unless a plug is inserted into the socket. The most common examples of normalised connectors are the insert points on a mixing console.

NYQUIST THEOREM: The rule which states that a digital sampling system must have a sample rate at least twice as high as that of the highest frequency being sampled in order to avoid aliasing. Because anti-aliasing filters aren't perfect, the sampling frequency has usually to be made more than twice that of the maximum input frequency.

NUT: Slotted plastic or bone component at the headstock end of a guitar neck used to guide the strings over the fingerboard, and to space the strings above the frets.

O

OCTAVE: When a frequency or pitch is transposed up by one octave, its frequency is doubled.

OFF-LINE: Process carried out while a recording is not playing. For example, some computer-based processes have to be carried out off-line as the computer isn't fast enough to carry out the process in real time.

OHM: Unit of electrical resistance.

OMNI: Meaning all, refers to a microphone that is equally sensitive in all directions, or to the MIDI mode where data on all channels is recognised.

OPEN CIRCUIT: A break in an electrical circuit that prevents current from flowing.

OPEN REEL: A tape machine where the tape is wound on spools rather than sealed in a cassette.

OPERATING SYSTEM: The basic software that enables a computer to load and run other programs.

OPTO ELECTRONIC DEVICE: A device where some electrical parameter changes in response to a variation in light intensity. Variable photoresistors are sometimes used as gain control elements in compressors where the side-chain signal modulates the light intensity.

OSCILLATOR: Circuit designed to generate a periodic electrical waveform.

OVERDUB: To add another part to a multitrack recording or to replace one of the existing parts.

OVERLOAD: To exceed the operating capacity of an electronic or electrical circuit.

P


PAD: Resistive circuit for reducing signal level.

PAN POT: Control enabling the user of a mixer to move the signal to any point in the stereo soundstage by varying the relative levels fed to the left and right stereo outputs.

PARALLEL: A means of connecting two or more circuits together so that their inputs are connected together, and their outputs are all connected together.

PARAMETER: A variable value that affects some aspect of a device's performance.

PARAMETRIC EQ: An equaliser with separate controls for frequency, bandwidth and cut/boost.

PASSIVE: A circuit with no active elements.

PATCH: Alternative term for Program, referring to a single programmed sound within a synthesizer that can be called up using Program Change commands. MIDI effects units and samplers also have patches.

PATCH BAY: A system of panel-mounted connectors used to bring inputs and outputs to a central point from where they can be routed using plug-in patch cords.

PATCH CORD: Short cable used with patch bays.

PEAK: Maximum instantaneous level of a signal.

PHASE: The timing difference between two electrical waveforms expressed in degrees where 360 degrees corresponds to a delay of exactly one cycle.

PHASER: Effect which combines a signal with a phase shifted version of itself to produce creative filtering effects. Most phasers are controlled by means of an LFO.

PEAK: The highest signal level in any section of programme material.

PFL: Pre Fade Listen; a system used within a mixing console to allow the operator to listen in on a selected signal, regardless of the position of the fader controlling that signal.

PPM: Peak Programme Meter; a meter designed to register signal peaks rather than the average level.

PHANTOM POWER: 48V DC supply for capacitor microphones, transmitted along the signal cores of a balanced mic cable.

PHASE: The timing difference between two electrical waveforms expressed in degrees where 360 degrees corresponds to a delay of exactly one cycle.

PHASER: Effect which combines a signal with a phase shifted version of itself to produce creative filtering effects. Most phasers are controlled by means of an LFO.

PHONO PLUG: Hi-Fi connector developed by RCA and used extensively on semi-pro, unbalanced recording equipment.

PICKUP: The part of a guitar that converts the string vibrations to electrical signals.

PITCH: Musical interpretation of an audio frequency.

PITCH BEND: A special control message specifically designed to produce a change in pitch in response to the movement of a pitch bend wheel or lever. Pitch bend data can be recorded and edited, just like any other MIDI controller data, even though it isn't part of the Controller message group.

PITCH SHIFTER: Device for changing the pitch of an audio signal without changing it's duration.

POLYPHONY: The ability of an instrument to play two or more notes simultaneously. An instrument which can only play one note at a time is described as monophonic.

POLY MODE: The most common MIDI mode that allows and instrument to respond to multiple simultaneous notes transmitted on a single MIDI channel.

PORT: Connection for the input or output of data.

PORTAMENTO: A gliding effect that allows a sound to change pitch at a gradual rate, rather than abruptly, when a new key is pressed or MIDI note sent.

POST PRODUCTION: Work done to a stereo recording after mixing is complete.

POWER SUPPLY: A unit designed to convert mains electricity to the voltages necessary to power an electronic circuit or device.

POST-FADE: Aux signal taken from after the channel fader so that the aux send level follows any channel fader changes. Normally used for feeding effects devices.

PPQN: Pulsed Per Quarter Note. Used in the context of MIDI Clock derived sync signals.

PRE-EMPHASIS: A system for applying high frequency boost to a sound before processing so as to reduce the effect of noise. A corresponding de-emphasis process is required on playback so as to restore the original signal, and to attenuate any high frequency noise contributed by the recording process.

PRE-FADE: Aux signal taken from before the channel fader so that the channel fader has no effect on the aux send level. Normally used for creating Foldback or Cue mixes.

PRESET: Effects unit or synth patch that cannot be altered by the user.

PRESSURE: Alternative term for Aftertouch.

PRINT THROUGH: The undesirable process that causes some magnetic information from a recorded analogue tape to become imprinted onto an adjacent layer. This can produce low level pre or post echoes.

PROCESSOR: Device designed to treat an audio signal by changing its dynamics or frequency content. Examples of processors include compressors, gates and equalisers.

PROGRAM CHANGE: MIDI message designed to change instrument or effects unit patches.

PULSE WAVE: Similar to a square wave but non-symmetrical. Pulse waves sound brighter and thinner than square waves, making them useful in the synthesis of reed instruments. The timbre changes according to the mark/space ratio of the waveform.

PULSE WIDTH MODULATION: A means of modulating the duty cycle (mark/space ratio) of a pulse wave. This changes the timbre of the basic tone; LFO modulation of pulse width can be used to produce a pseudo-chorus effect.

PUNCH IN: The action of placing an already recorded track into record at the correct time during playback, so that the existing material may be extended or replaced.

PUNCH OUT: The action of switching a tape machine (or other recording device), out of record after executing a punch-in. With most multitrack machines, both
punching in and punching out can be accomplished without stopping the tape.

PQ CODING: Process for adding Pause, Cue and other subcode information to a digital master tape in preparation for CD manufacture.

PZM: Pressure Zone Microphone. A type of boundary microphone. Designed to reject out-of-phase sounds reflected from surfaces within the recording environment.

Q

Q: A measure of the resonant properties of a filter. The higher the Q, the more resonant the filter and the narrower the range of frequencies that are allowed to pass. This will be explained in more detail when we talk about filters later in the series.
QUANTIZE: A means of moving notes recorded in a MIDI sequencer so that they line up with user defined subdivisions of a musical bar, for example, 16s. The facility may be used to correct timing errors, but over-quantization can remove the human feel from a performance.

R

RAM: Abbreviation for Random Access Memory. This is a type of memory used by computers for the temporary storage of programs and data, and all data is lost when the power is turned off. For that reason, work needs to be saved to disk if it is not to be lost.

R-DAT: Digital tape machine using a rotating head system.

REAL TIME: An audio process that can be carried out as the signal is being recorded or played back. The opposite is off-line, where the signal is processed in non-real time.

RELEASE: The time taken for a level or gain to return to normal. Often used to describe the rate at which a synthesized sound reduces in level after a key has been released.

RESISTANCE: Opposition to the flow of electrical current. Measured in Ohms.

RESOLUTION: The accuracy with which an analogue signal is represented by a digitising system. The more bits are used, the more accurately the amplitude of each sample can be measured, but there are other elements of converter design that also affect accuracy. High conversion accuracy is known as high resolution.

RESONANCE: Same as Q.

REVERB: Acoustic ambience created by multiple reflections in a confined space.

RF: Radio Frequency.

RF Interference: Interference significantly above the range of human hearing.

RIBBON MICROPHONE: A microphone where the sound capturing element is a thin metal ribbon suspended in a magnetic filed. When sound causes the ribbon to vibrate, a small electrical current is generated within the ribbon.

ROLL-OFF: The rate at which a filter attenuates a signal once it has passed the filter cut-off point.

ROM: Abbreviation for Read Only Memory. This is a permanent or non-volatile type of memory containing data that can't be changed. Operating systems are often stored on ROM as the memory remains intact when the power is removed.

E-PROM: (Erasable Programmable Read Only Memory) Similar to ROM, but the information on the chip can be erased and replaced using special equipment.

RELEASE: The rate at which a signal amplitude decays once a key has been released.

RESONANCE: The characteristic of a filter that allows it to selectively pass a narrow range of frequencies.

RING MODULATOR: A device that accepts and processes two input signals in a particular way. The output signal does not contain any of the original input signal but instead comprises new frequencies based on the sum and difference of the input signals' frequency components. Ring Modulators will be covered in depth later in the series. The best known application of Ring Modulation is the creation of Dalek voices but it may also be used to create dramatic instrumental textures. Depending on the relationships between the input signals, the results may either be musical or extremely dissonant - for example, ring modulation can be used to create bell-like tones. (The term 'Ring' is used because the original circuit which produced the effect used a ring of diodes.)

RMS: (Root Mean Square) A method of specifying the behaviour of a piece of electrical equipment under continuous sine wave testing conditions.

S

SAFETY COPY: Copy or clone of an original tape for use in case of loss or damage to the original.

SAMPLE: The process carried out by an A/D converter where the instantaneous amplitude of a signal is measured many times per second (44.1kHz in the case of CD).

SAMPLE: A digitised sound used as a musical sound source in a sampler or additive synthesizer.

SAMPLE RATE: The number of time an A/D converter samples the incoming waveform each second.

SAMPLE AND HOLD: Usually refers to a feature whereby random values are generated at regular intervals and then used to control another function such as pitch or filter frequency. Sample and hold circuits were also used in old analogue synthesizers to 'remember' the note being played after a key had been released.

SCSI: (Pronounced SKUZZY) Abbreviation for Small Computer Systems Interface. An interfacing system for using hard drives, scanners, CD-ROM drives and similar peripherals with a computer. Each SCSI device has its own ID number and no two SCSI devices in the same chain must be set to the same number. The last SCSI device in the chain should be terminated, either via an internal terminator, where provided or via a plug-in terminator fitted to a free SCSI socket.

SESSION TAPE: The original tape made during a recording session.

SEQUENCER: Device for recording and replaying MIDI data, usually in a multitrack format, allowing complex compositions to be built up a part at a time.

SHORT CIRCUIT: A low resistance path that allows electrical current to flow. The term is usually used to describe a current path that exists through a fault condition.

SIBILANCE: High frequency whistling or lisping sound that affects vocal recordings, due either to poor mic technique or excessive equalisation.

SIDE CHAIN: A part of the circuit that splits off a proportion of the main signal to be processed in some way. Compressor use the side-chain signal to derive their control signals.

SIGNAL: Electrical representation of input such as sound.

SIGNAL CHAIN: Route taken by a signal from the input to a system to the output.

SIGNAL-TO-NOISE RATIO: The ratio of maximum signal level to the residual noise, expressed in dBs.

SINE WAVE: The waveform of a pure tone with no harmonics.

SINGLE ENDED NOISE REDUCTION: A device for removing or attenuating the noise component of a signal, but that doesn't require previous coding, as in the case of Dolby or dbx.

SLAVE: A device under the control of a master device.

SMPTE: Time code developed for the film industry but now extensively used in music and recording. SMPTE is a real-time code and is related to hours, minutes, seconds and film or video frames rather than to musical tempo.

SOUND ON SOUND: Early recording technique to allow pseudo-multitracking. Also, the world's best music recording technology magazine.

S/PDIF — Acronym for "Sony/Philips Digital Inter Face". [ Also sometimes referred to by its common "standards" title of IEC958 (type-2). It also conforms with the EIAJ standard of CP-340 (type-2), now renumbered to CP-1201 ]. The S/PDIF digital data format is very similar to the professional AES-EBU standard although it uses different electrical characteristics. The system normally carries 16 or 20-bit data, although it can accommodate 24-bits of audio data per channel. Extra information can also be carried along side the audio such as track start flags, source identification information, and timing data.
The electrical interface is unbalanced and normally employs phono connectors. The source impedance of 75 Ohms and high signal frequencies (0.1 to 6MHz) require good quality 75-Ohm co-axial (RF) cable to operate reliably. Also, as the source amplitude of the data signal is only 0.5V peak-to-peak this restricts the transmission distance to short cable runs of up to about 10 metres.
An optical version of the interface is also available known as "TOSLink" which transmits the same data signals as the electrical IEC958. This is achieved with an LED transmitter and an opto-sensor as the receiver. High quality optical interfaces offer several advantages in terms of galvanic isolation and freedom from electro-magnetic interference, but cheap fibre-optic cables suffer from restricted bandwidths and high dispersion which result in severe timing instability and data errors.

SPL: Sound Pressure Level measured in dBs.

SPP: Song Position Pointer (MIDI).

STANDARD MIDI FILE: A standard file format that allows MIDI files to be transferred between different sequencers and MIDI file players.

STEMS: When mixing complex audio material it is often useful to divide the tracks into related sections and mix those sections separately before combining the whole. In mixing film soundtracks, the material would often be grouped as a dialogue stem, a music stem, an effects stem and so on. Each stem might be mono, stereo or multichannel, as appropriate to the situation. In music mixing, stems might be used for the rhythm section, backline instruments, frontline instruments, backing vocals, lead vocals and effects — or any other combination that suited the particular project.

STEP TIME: A system for programming a sequencer in non-real time.

STEREO: two-channel system feeding left and right loudspeakers.

STICKY SHED SYNDROME: A problem affecting some brands of analogue tape after a long time in storage. A breakdown of the binder causes the oxide to shed, and the tape tends to adhere to the tape heads and guides when played. A short term cure can be affected by baking the affected tape for several hours at 50 degrees C.

STRIPE: To record time code onto one track of a multitrack tape machine.

SQUARE WAVE: A symmetrical rectangular waveform. Square waves contain a series of odd harmonics.

SAWTOOTH WAVE: So called because it resembles the teeth of a saw, this waveform contains both odd and even harmonics.

SUB BASS: Frequencies below the range of typical monitor loudspeakers. Some define sub-bass as frequencies that can be felt rather than heard.

SUBCODE: Hidden data within the CD and DAT format that includes such information as the absolute time location, number of tracks, total running time and so on.

SUBTRACTIVE SYNTHESIS: The process of creating a new sound by filtering and shaping a raw, harmonically complex waveform.

SURGE: Sudden increase in mains voltage.

SUSTAIN: Part of the ADSR envelope which determines the level to which the sound will settle if a key is held down. Once the key is released, the sound decays at a rate set by the Release parameter. Also refers to a guitar's ability to hold notes which decay very slowly.

SWEET SPOT: The optimum position for a microphone, or for a listener relative to monitor loudspeakers.

SWITCHING POWER SUPPLY: A type of power supply that uses a high frequency oscillator prior to the transformer so that a smaller, lighter transformer may be used. These power supplies are commonly used in computers and some synthesizer modules.

SYNC: A system for making two or more pieces of equipment run in synchronism with each other.

SYNTHESIZER: Electronic musical instrument designed to create a wide range of sounds, both imitative and abstract.

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