by Bruce Bartlett

A-B: A listening comparison between two audio programs, or between two components playing the same program, performed by switching immediately from one to the other. The levels of the two signals are matched. See also Spaced-Pair.

AES: Audio Engineering Society.

AES/EBU: Also called IEC 988 Tape 1, an interface format for digital signals, using a balanced 110 ohm mic cable terminated with XLR-type connectors. See also S/PDIF.

A WEIGHTING: See Weighted.

ACCENT MICROPHONE: See Spot Microphone.

ACCESS JACKS: Two jacks in a console input module or output module that allow access to points in the signal path, usually for connecting a compressor. Plugging into the access jacks breaks the signal flow and allows you to insert a signal processor in series with the signal.

ACTIVE COMBINING NETWORK: A combining network with gain. See Combining Network.

ALIGNMENT: The adjustment of tape-head azimuth and of tape-recorder circuitry to achieve optimum performance from the particular type of tape being used.

ALIGNMENT TAPE: A prerecorded tape with calibrated tones for alignment of a tape recorder.

AMBIENCE: Room acoustics, early reflections and reverberation. Also, the audible sense of a room or environment surrounding a recorded instrument.

AMBIENCE MICROPHONE: A microphone placed relatively far from its sound source to pick up ambience.

AMPLITUDE, PEAK: On a graph of a sound wave, the sound pressure of the waveform peak. On a graph of an electrical signal, the voltage of the waveform peak. The amplitude of a sound wave or signal as measured on a meter is 0.707 times the peak amplitude.

ANALOG-TO-DIGITAL (A/D) CONVERTER: A circuit that converts an analog audio signal into a stream of digital data (bit stream).

ASSIGN: To route or send an audio signal to one or more selected channels.

ATRAC: Adaptive Transform Acoustic Coding. A data compression scheme that reduces by 5:1 the storage needed for digital audio. ATRAC is a perceptual coding method, which omits data deemed inaudible due to masking.

ATTACK: The beginning of a note. The first portion of a note's envelope in which a note rises from silence to its maximum volume.

ATTACK TIME: In a compressor, the time it takes for gain reduction to occur in response to a musical attack.

ATTENUATE: To reduce the level of a signal.

ATTENUATOR: In a mixer (or mixing console) input module, an adjustable resistive network that reduces the microphone signal level to prevent overloading of the input transformer and mic preamplifier.

AUTOLOCATE: A recorder function which makes the tape or disk go to a program address (counter time) at the press of a button.

AUTOMATED MIXING: A system of mixing in which a computer remembers and updates console settings. With this system, a mix can be performed and refined in several stages and played back at a later date exactly as set u previously.



A/V DRIVE: A hard disk drive meant for audio/video use. It postpones thermal recalibration until the disk is inactive, preventing data errors.

AZIMUTH: In a tape recorder, the angular relationship between the head gap and the tape path.

AZIMUTH ALIGNMENT: The mechanical adjustment of the record or playback head to bring it into proper alignment (90 degrees) with the tape path.

BACK-TIMING: A technique of cueing up the musical background or a sound effect to a narration track so that the music or effect ends simultanously with the narration.

BAFFLED-OMNI: A stereo miking arrangment that uses two ear-spaced omnidirectional microphones separated by a hard padded baffle.

BALANCE: The relative volume levels of various tracks or instruments.

BALANCED AC POWER: AC power from a center-tapped power transformer. Instead of one 120V line and one 0V line, it has two 60V lines. They are in phase with each other, and sum to 120V. But they are connected to the center-tap ground out of phase (one is +60V; the other is -60V). Any hum and noise on the grounding system cancels out.

BALANCED LINE: A cable with two conductors surrounded by a shield, in which each conductor is at equal impedance to ground. With respect to ground, the conductors are at equal potential but opposite polarity; the signal flows through both conductors.

BANDPASS FILTER: In a crossover, a filter that passes a band or range of frequencies but sharply attenuates or rejects frequencies outside the band.

BASIC TRACKS: Recorded tracks of rhythm instruments (bass, guitar, drums, and sometimes keyboard).

BASS TRAP: An assembly that absorbs low-frequency sound waves in the studio.

BIAMPLIFICATION (BIAMPING): Driving a woofer and tweeter with separate power amplfiers. An active crossover is connected ahead of these power amplifiers.

BIAS: In tape-recorder electronics, an ultrasonic signal that drives the erase head. This signal is also mixed with the audio signal applied to the record head to reduce distortion.

BIDIRECTIONAL MICROPHONE: A microphone that is most sensitive to sounds arriving from two directions--in front of and behind the microphone. It rejects sounds approaching either side of the microphone. Sometimes called a cosine or figure-eight microphone because of the shape of its polar pattern.

BINAURAL RECORDING: A 2-channel recording made with an omnidirectional microphone mounted near each ear of a human or a dummy head, for playback over headphones. The object is to duplicate the acoustic signal appearing at each ear.

BLUMLEIN ARRAY: A stereo microphone technique in which two coincident bidirectional microphones are angled 90 degrees apart (45 degrees to the left and right of center).

BOARD: See Mixing Console.

BOUNCING TRACKS: A process in which two or more tracks are mixed, and the mixed tracks are recorded on an unused track or tracks. Then the original tracks can be erased, which frees them up for recording more instruments.

BOUNDARY MICROPHONE: A microphone designed to be used on a boundary (a hard reflective surface). The microphone capsule is mounted very close to the boundary so that direct and reflected sounds arrive at the microphone diaphragm in phase (or nearly so) for all frequencies in the audible band.

BREATHING: The unwanted audible rise and fall of background noise that may occur with a compressor. Also called pumping.

BULK TAPE ERASER: A large electromagnet used to erase a whole reel of recording tape at once.

BUS: A common connection of many different signals. An output of a mixer or submixer. A channel that feeds a tape track, signal processor, or power amplifier.

BUS IN: An input to a program bus, usually used for effects returns.

BUS MASTER: In the output section of a mixing console, a potentiometer (fader or volume control) that controls the output level of a bus.

BUS OUT: The output connector of a bus.

BUS TRIM: A control in the output section of a mixing console that provides variable gain control of a bus, used in addition to the bus master for fine adjustment.

BUS MASTER: In the output section of a mixing console, a potentiometer (fader or volume control) that controls the output level of a bus.

BUZZ: An unwanted edgy tone that sometimes accompanies audio, containing high harmonics of 60 Hz.

CALIBRATION: See Alignment.

CAPACITOR: An electronic component that stores an electric charge. It is formed of two conductive plates separated by an insulator called a dielectric. A capacitor passes AC but blocks DC.

CAPACITOR MICROPHONE: See Condenser Microphone.

CAPSTAN: In a tape-recorder transport, a rotating post that contacts the tape (along with the pinch roller) and pulls the tape past the heads at a constant speed during recording and playback.

CARDIOID MICROPHONE: A unidirectional microphone with side attenuation of 6 dB and maximum rejection of sound at the rear of the microphone (180 degrees off-axis). A microphone with a heart-shaped directional pattern.

CD-R: CD-Recordable, a recordable compact disc that cannot be rewritten. Once recorded, it cannot be erased and reused.

CD-RW: CD-Rewritable, a recordable compact disc that can be rewritten. Once recorded it can be erased and reused. CHANNEL: A single path of an audio signal. Usually, each channel contains a different signal.


CHORUS: 1. A special effect in which a signal is delayed by 15 to 35 milliseconds, the delayed signal is combined with the original signal, and the delay is varied randomly or periodically. This creates a wavy, shimmering effect. 2. The main portion of a song that is repeated several times throughout the song with the same lyrics.

CLEAN: Free of noise, distortion, overhang, leakage. Not muddy.

CLEAR: Easy to hear, easy to differentiate. Reproduced with sufficient high frequencies.

COINCIDENT-PAIR: A stereo microphone, or two separate microphones, placed so that the microphone diaphragms occupy approximately the same point in space. They are angled apart and mounted one directly above the other.

COMB-FILTER EFFECT: The frequency response caused by combining a sound with its delayed replica. The frequency response has a series of peaks and dips caused by phase interference. The peaks and dips resemble the teeth of a comb.

COMBINING AMPLIFIER: An amplifier at which the outputs of two or more signal paths are mixed together to feed a single track of a tape recorder.

COMBINING NETWORK: A resistive network at which the outputs of two or more signal paths are mixed together to feed a single track of a tape recorder.

COMPLEX WAVE: A wave with more than one frequency component.

COMPING: Recording composite tracks.

COMPOSITE TRACKS: The process of recording several performances of a musical part on different tracks, so that the best segments of each performance can be played in sequence during mixdown.

COMPRESSION: 1. The portion of a sound wave in which molecules are pushed together, forming a region with higher-than-normal atmospheric pressure. 2. In signal processing, the reduction in dynamic range or gain caused by a compressor. 3. In computing, data compression reduces the number of bytes in a file without losing essential information.

COMPRESSION RATIO (SLOPE): In a compressor, the ratio of the change in input level (in dB) to the change in output level (in dB). For example, a 2:1 ratio means that for every 2 dB change in input level, the output level changes 1 dB.

COMPRESSOR: A signal processor that reduces dynamic range or gain by means of automatic volume control. An amplifier whose gain decreases as the input signal level increases above a preset point.

CONDENSER MICROPHONE: A microphone that works on the principle of variable capacitance to generate an electrical signal. The microphone diaphragm and an adjacent metallic disk (called a backplate) are charged to form two plates of a capacitor. Incoming sound waves vibrate the diaphragm, varying its spacing to the backplate, which varies the capacitance, which in turn varies the voltage between the diaphragm and backplate.

CONNECTOR: A device that makes electrical contact between a signal-carrying cable and an electronic device, or between two cables. A device used to connect or hold together a cable and an electronic component so that a signal can flow from one to the other.

CONSOLE: See Mixing Console.

CONTACT PICKUP: A transducer that contacts a musical instrument and converts its mechanical vibrations into a corresponding electrical signal.

CONTROL ROOM: The room in which the engineer controls and monitors the recording. It houses most of the recording hardware.

CROSSOVER: An electronic network that divides an incoming signal into two or more frequency bands.

CROSSOVER, ACTIVE (ELECTRONIC CROSSOVER): A crossover with amplifying components, used ahead of the power amplifiers in a biamped or triamped speaker system.

CROSSOVER FREQUENCY: The single frequency at which both filters of a crossover network are down 3 dB.

CROSSOVER, PASSIVE: A crossover with passive (nonamplifying) components, used after the power amplifier.

CROSSTALK: The unwanted transfer of a signal from one channel to another. Crosstalk often occurs between adjacent tracks within a record or playback head in a tape recorder, or between input modules in a console.

CUE, CUE SEND: In a mixing-console input module, a control that adjusts the level of the signal feeding the cue mixer that feeds a signal to headphones in the studio.

CUE LIST: See Edit Decision List.

CUE MIXER: A submixer in a mixing console that takes signals from cue sends as inputs and mixes them into a composite signal that drives headphones in the studio.

CUE SHEET: Used during mixdown, a chronological list of mixing-console control adjustments required at various points in the recorded song. These points may be indicated by tape-counter or ABS-time readings.

CUE SYSTEM: A monitor system that allows musicians to hear themselves and previously recorded tracks through headphones.

DAMPING FACTOR: The ability of a power amplifier to control or damp loudspeaker vibrations. The lower the amplifier's output impedance, the higher the damping factor.

DAT (R-DAT): A digital audio tape recorder that uses a rotating head to record digital audio on tape.

DATA COMPRESSION: A scheme for reducing the amount of data storage on a medium. See ATRAC.

DAW: Abbreviation for digital audio workstation.

dB: Abbreviation for decibel.

DEAD: Having very little or no reverberation.

DECAY: The portion of the envelope of a note in which the envelope goes from maximum to some midrange level. Also, the decline in level of reverberation over time.

DECAY TIME: See Reverberation time.

DECIBEL: The unit of measurement of audio level. Ten times the logarithm of the ratio of two power levels. Twenty times the logarithm of the ratio of two voltages.

dBV is decibels relative to 1 volt. dBu is decibels relative to 0.775 volt. dBm is decibels relative to 1 milliwatt. dBA is decibels, A weighted (see Weighted)

DECODED TAPE: A tape that is expanded after being compressed by a noise-reduction system. Such a tape has normal dynamic range.

DE-ESSER: A signal processor that removes excessive sibilance ("s" and "sh" sounds) by compressing high frequencies around 5 to 10 kHz.

DELAY: The time interval between a signal and its repetition. A digital delay or a delay line is a signal processor that delays a signal for a short time.

DEMAGNETIZER (DEGAUSSER): An electromagnet with a probe tip that is touched to elements of the tape path (such as tape heads and tape guides) to remove residual magnetism.

DEPTH: The audible sense of nearness and farness of various instruments. Instruments recorded with a high ratio of direct-to-reverberant sound are perceived as being close; instruments recorded with a low ratio of direct-to-reverberant sound are perceived as being distant.

DESIGN CENTER: The portion of fader travel (usually shaded), about 10 to 15 dB from the top, in which console gain is distributed for optimum headroom and signal-to-noise ratio. During normal operation, each fader in use should be placed at or near design center.

DESIGNATION STRIP: A strip of paper taped near console faders to designate the instrument that each fader controls.

DESK: The British term for mixing console.

DESTRUCTIVE EDITING: In a digital audio workstation, editing that rewrites the data on disk. A destructive edit cannot be undone.

DI: Short for direct injection, recording with a direct box.

DIFFUSION: An even distribution of sound in a room.

DIGITAL AUDIO: An encoding of an analog audio signal in the form of binary digits (ones and zeros).

DIGITAL AUDIO WORKSTATION (DAW): A computer, sound card, and editing software that allows you to record, edit and mix audio programs entirely in digital form. Stand-alone DAWs include real mixer controls; computer DAWS have virtual controls on-screen.

DIGITAL RECORDING: A recording system in which the audio signal is stored in the form of binary digits.

DIGITAL-TO-ANALOG CONVERTER: A circuit that converts a digital audio signal into an analog audio signal.

DIM: To reduce the monitor volume temporarily by a preset amount so that you can carry on a conversation.

DIRECT BOX: A device used for connecting an amplified instrument directly to a mixer mic input. The direct box converts a high-impedance unbalanced audio signal into a low-impedance balanced audio signal.

DIRECT INJECTION (DI): Recording with a direct box.

DIRECTIONAL MICROPHONE: A microphone that has different sensitivity in different directions. A unidirectional or bidirectional microphone.

DIRECT OUTPUT, DIRECT OUT: An output connector following a mic preamplifier, fader and equalizer, used to feed the signal of one instrument to one track of a tape recorder.

DIRECT SOUND: Sound traveling directly from the sound source to the microphone (or to the listener) without reflections.

DISTORTION: An unwanted change in the audio waveform, causing a raspy or gritty sound quality. The appearance of frequencies in a device's output signal that were not in the input signal. Distortion is caused by recording at too high a level, improper mixer settings, components failing, or vacuum tubes distorting. (Distortion can be desirable--for an electric guitar, for example.)

DOLBY TONE: A reference tone recorded at the beginning of a Dolby-encoded tape for alignment purposes.

DOUBLING: A special effect in which a signal is combined with its 15 to 35 millisecond delayed replica. This process mimics the sound of two identical voices or instruments playing in unison. In another type of doubling, two indentical performances are recorded and played back to thicken the sound.

DROP-FRAME: For color video production, a mode of SMPTE time code that causes the time code to match the clock on the wall. Once every minute, frame numbers 00 and 01 are dropped, except every 10th minute.

DROP-OUT: During playback of a tape recording, a momentary loss of signal caused by separation of the tape from the playback head by dust, tape-oxide irregularity, etc.

DRUM MACHINE: A device that plays samples of real drums, and includes a sequencer to record rhythm patterns.

DRY: Having no echo or reverberation. Referring to a close- sounding signal that is not yet processed by a reverberation or delay device.

DSP: Abbreviation for Digital Signal Processing, modifying a signal in digital form.

DVD: Digital Versatile Disc. A storage medium the size of a compact disc which holds much more data. The DVD stores video, audio, or computer data.

DYNAMIC MICROPHONE: A microphone that generates electricity when sound waves cause a conductor to vibrate in a stationary magnetic field. The two types of dynamic microphone are moving coil and ribbon. A moving-coil microphone is usually called a dynamic microphone.

DYNAMIC RANGE: The range of volume levels in a program from softest to loudest.

EARTH GROUND: A connection to moist dirt (the ground we walk on). This connection is usually done via a long copper rod or an all-metal cold-water pipe.

ECHO: A delayed repetition of a signal or sound. A sound delayed 50 milliseconds or more, combined with the original sound.

ECHO CHAMBER: A hard-surfaced room containing a widely separated loudspeaker and microphone, once used for creating reverberation.

EDIT DECISION LIST (EDL): A list of program events in order, plus their starting and ending times.

EDITING: The cutting and rejoining of magnetic tape to delete unwanted material, to insert leader tape, or to rearrange recorded material into the desired sequence. Also, the same actions performed with a digital audio workstation, hard-disk recorder, or MiniDisc recorder-mixer--without cutting any tape.

EDITING BLOCK: A metal block that holds magnetic tape during the editing/splicing procedure.

EFFECTS: Interesting sound phenomena created by signal processors, such as reverberation, echo, flanging, doubling, compression, or chorus.

EFFECTS BUS: The bus that feeds effects devices (signal processors).

EFFECTS LOOP: A set of connectors in a mixer for connecting an external effects unit, such as a reverb or delay device. The effects loop includes a send section and a receive section. See Effects Send, Effects Return.

EFFECTS MIXER: A submixer in a mixing console that combines signals from effects sends, and then feeds the mixed signal to the input of a special-effects device, such as a reverberation unit.

EFFECTS RETURN (EFFECTS RECEIVE): In the output section of a mixing console, a control that adjusts the amount of signal received from an effects unit. Also, the connectors in a mixer to which you connect the effects-unit output signal. They might be labeled "bus in" instead. The effects-return signal is mixed with the program bus signal.

EFFECTS SEND: In an input module of a mixing console, a control that adjusts the amount of signal sent to a special-effects device, such as a reverberation or delay unit. Also, the connector in a mixer which you connect to the input of an effects unit. The effects-send control normally adjusts the amount of reverberation or echo heard on each instrument.

EFFICIENCY: In a loudspeaker, the ratio of acoustic power output to electrical power input.

EIA: Electrical Industries Association.

EIA RATING: A microphone-sensitivity specification that states the microphone output level in dBm into a matched load for a given Sound Pressure Level (SPL). SPL + dB (EIA rating) = dBm output into a matched load.

ELECTRET-CONDENSER MICROPHONE: A condenser microphone in which the electrostatic field of the capacitor is generated by an electret--a material that permanently stores an electrostatic charge.

ELECTROSTATIC FIELD: The force field between two conductors charged with static electricity.

ELECTROSTATIC INTERFERENCE: The unwanted presence of an electrostatic hum field in signal conductors.

ENCODED TAPE: A tape containing a signal compressed by a noise-reduction unit.

END-ADDRESSED: Referring to a microphone whose main axis of pickup is perpendicular to the front of the microphone. You aim the front of the mic at the sound source. See Side-Addressed.

ENVELOPE: The rise and fall in volume of one note. The envelope connects successive peaks of the waves comprising a note. Each harmonic in the note might have a different envelope.

EQUALIZATION (EQ): The adjustment of frequency response to alter the tonal balance or to attenuate unwanted frequencies.

EQUALIZER: A circuit (usually in each input module of a mixing console, or in a separate unit) that alters the frequency spectrum of a signal passed through it.

ERASE: To remove an audio signal from magnetic tape by applying an ultrasonic varying magnetic field so as to randomize the magnetization of the magnetic particles on the tape.

ERASE HEAD: A head in a tape recorder that erases the signal on tape.

EXPANDER: 1. A signal processor that increases the dynamic range of a signal passed through it. 2. An amplifer whose gain decreases as its input level decreases. When used as a noise gate, an expander reduces the gain of low-level signals to reduce noise between notes.

FADE-OUT: To gradually reduce the volume of the last several seconds of a recorded song, from full level down to silence, by slowly pulling down the master fader.

FADER: A linear or sliding potentiometer (volume control), used to adjust signal level.

FEED: 1. To send an audio signal to some device or system. 2. An output signal sent to some device or system.

FEEDBACK: 1. The return of some portion of an output signal to the system's input. 2. The squealing sound you hear when a PA system microphone picks up its own amplified signal through a loudspeaker.

FEED REEL: The left-side reel on a tape recorder that unwinds during recording or playback.

FILTER: 1. A circuit that sharply attenuates frequencies above or below a certain frequency. Used to reduce noise and leakage above or below the frequency range of an instrument or voice. 2. A MIDI Filter removes selected note parameters.

FLANGING: A special effect in which a signal is combined with its delayed replica, and the delay is varied between 0 and 20 milliseconds. A hollow, swishing, ethereal effect like a variable-length pipe, or like a jet plane passing overhead. A variable comb filter produces the flanging effect.

FLETCHER MUNSON EFFECT: Named after the two people who discovered it, the psychoacoustical phenomenon in which the subjective frequency response of the ear changes with program level. Due to this effect, a program played at a lower volume than the original level subjectively loses low- and high-frequency response.

FLOAT: To disconnect from ground.

FLUTTER: A rapid periodic variation in tape speed.

FLUTTER ECHOES: A rapid series of echoes that occurs between two parallel walls.

FLUX: Magnetic lines of force.

FLUXIVITY: The measure of the flux density of a magnetic recording tape, per unit of track width.

FLY-IN (LAY-IN)--To copy part of a recorded track onto another recorder, then re-record that copy back onto the original multitrack tape in a different part of the song, in sync with other recorded tracks. For example, copy the vocal track from the first chorus of the song onto an external recorder or sampler. Rerecord (fly-in) that copy onto the multitrack tape at the second chorus. Then the first and second choruses have identical vocal performances.

FOLDBACK (FB): See Cue System.

FREQUENCY: The number of cycles per second of a sound wave or an audio signal, measured in hertz (Hz). A low frequency (for example, 100 Hz) has a low pitch; a high frequency (for example, 10,000 Hz) has a high pitch.

FREQUENCY RESPONSE: 1. The range of frequencies that an audio device will reproduce at an equal level (within a tolerance, such as +/- 3 dB). 2. The range of frequencies that a device (mic, human ear, etc.) can detect.

FULL TRACK: A single tape track recorded across the full width of a tape.

FUNDAMENTAL: The lowest frequency in a complex wave.

GAIN: Amplification. The ratio, expressed in decibels, between the output voltage and the input voltage, or between the output power and the input power.

GAP: In a tape-recorder head, the thin break in the electromagnet that contacts the tape.

GATE: 1. To turn off a signal when its amplitude falls below a pre-set value. 2. The signal-processing device used for this purpose. See also Noise Gate.

GATED REVERB: Reverberation with the reverberant "tail" cut off before it fades out.

GENERATION: A copy of a tape or a bounce of a track. A copy of the original master recording is a first generation tape. A copy made from the first generation tape is a second generation, and so on.

GENERATION LOSS: The degradation of signal quality (the increase in noise and distortion) that occurs with each successive generation of a tape recording.

GOBO: A moveable partition used to prevent the sound of an instrument from reaching another instrument's microphone. Short for go-between.

GRAPHIC EQUALIZER: An equalizer with a horizontal row of faders; the fader-knob positions indicate graphically the frequency response of the equalizer. Usually used to equalize monitor speakers for the room they are in. Sometimes used for complex EQ of a track.

GROUND: The zero-signal reference point for a system of audio components.

GROUND BUS: A common connection to which equipment is grounded, ususally a heavy copper plate.

GROUNDING: Connecting pieces of electronic equipment to ground. Proper grounding ensures that there is no voltage difference between equipment chassis. An electrostatic shield needs to be grounded to be effective.

GROUND LOOP: 1. A loop or circuit formed of ground leads. 2. The loop formed when unbalanced components are connected together via two ground paths--the connecting-cable shield and the power ground. Ground loops cause hum and should be avoided.

GROUP: See Submix.

GUARD BAND: The spacing between tracks on a multitrack tape or tape head, used to prevent crosstalk.

HALF-TRACK: A tape track recorded across approximately half the width of a tape. A half-track recorder usually records two such tracks simultaneously in the same direction to make a stereo recording.

HARD DISK: A random-access storage medium for computer data. A hard disk drive contains a stack of magnetically coated hard disks that are read by, and written to by, an electromagnetic head.

HARD DISK RECORDER: A device dedicated to recording digital audio on a hard disk drive. A hard disk recorder-mixer includes a built-in mixer.

HARMONIC: An overtone whose frequency is a whole-number multiple of the fundamental frequency.

HARMONIZER: A signal processor that provides a wide variety of pitch-shifting and delay effects.

HEAD: An electromagnet in a tape recorder that either erases the audio signal on tape, records a signal on tape, or plays back a signal that is already on tape.

HEAD GAP: See Gap.

HEADPHONES: A head-worn transducer that covers the ears and converts electrical audio signals into sound waves.

HEADROOM: The safety margin, measured in decibels, between the signal level and the maximum undistorted signal level. In a tape recorder, the dB difference between standard operating level (corresponding to a 0 VU reading) and the level causing 3 percent total harmonic distortion. High-frequency headroom increases with analog tape speed.

HERTZ (Hz): Cycles per second, the unit of measurement of frequency.

HIGHPASS FILTER: A filter that passes frequencies above a certain frequency and attenuates frequencies below that same frequency. A low-cut filter.

HISS: A noise signal containing all frequencies, but with greater energy at higher octaves. Hiss sounds like wind blowing through trees. It is usually caused by random signals generated by microphones, electronics, and magnetic tape.

HOT: 1. A high recording level causing slight distortion, maybe used for special effect. 2. A condition in which a chassis or circuit has a potentially dangerous voltage on it. 3. Referring to the conductor in a microphone cable which has a positive voltage on it at the instant that sound pressure moves the diaphragm inward.

HUM: An unwanted low-pitched tone (60 Hz and its harmonics) heard in the monitors. The sound of interference generated in audio circuits and cables by AC power wiring. Hum pickup is caused by such things as faulty grounding, poor shielding, and ground loops.

HYPERCARDIOID MICROPHONE: A directional microphone with a polar pattern that has 12 dB attenuation at the sides, 6 dB attenuation at the rear, and two nulls of maximum rejection at 110 degrees off axis.

IMAGE: An illusory sound source located somewhere around the listener. An image is generated by two or more loudspeakers. In a typical stereo system, images are located between the two stereo speakers.

IMPEDANCE: The opposition of a circuit to the flow of alternating current. Impedance is the complex sum of resistance and reactance. Abbreviated as Z.

INPUT: The connection going into an audio device. In a mixer or mixing console, a connector for a microphone, line-level device, or other signal source.


INPUT MODULE: In a mixing console, the set of controls affecting a single input signal. An input module usually include an attenuator (trim), fader, equalizer, effects send, cue send, and channel-assign controls.

INPUT SECTION: The row of input modules in a mixing console.

INPUT/OUTPUT (I/O) CONSOLE (IN-LINE CONSOLE): A mixing console arranged so that input and output sections are aligned vertically. Each module (other than the monitor section) contains one input channel and one output channel.

INSERT JACKS: See Access jacks.

JACK: A female or receptacle-type connector for audio signals into which a plug is inserted.

KEYBOARD WORKSTATION: Several MIDI components in one chassis--a keyboard, a sample player, a sequencer, and perhaps a synthesizer and disk drive.

KILO: A prefix meaning one thousand. Abbreviated k.

LAY-IN: See Fly-In.

LEADERING: The process of splicing leader tape between program selections.

LEADER TAPE: Plastic or paper tape without an oxide coating, used for a spacer between takes (for silence between songs).

LEAKAGE: The overlap of an instrument's sound into another instrument's microphone. Also called bleed or spill.

LEDE: Abbreviation for Live-End/Dead-End, a type of control room acoustic treatment in which the front half of the control room prevents early reflections to the mixing position, while the back half of the control room reflects diffused sound to the mixing position.

LED INDICATOR: A recording-level indicator using one or more Light Emitting Diodes.

LEVEL: The degree of intensity of an audio signal--the voltage, power, or sound pressure level. The original definition of level is the power in watts.

LEVEL SETTING: In a recording system, the process of adjusting the input-signal level to obtain maximum level on the recording media without distortion. A VU meter or other indicator shows recording level.

LIMITER: A signal processor whose output is constant above a preset input level. A compressor with a compression ratio of 10:1 or greater, with the threshold set just below the point of distortion of the following device. Used to prevent distortion of attack transients or peaks.

LINE LEVEL: In balanced professional recording equipment, a signal whose level is approximately 1.23 volts (+4 dBm). In unbalanced equipment (most home hi-fi or semipro recording equipment), a signal whose level is approximately 0.316 volt (-10 dBV).

LIVE: 1. Having audible reverberation. 2. Occuring in real-time, in person.

LIVE RECORDING: A recording made at a concert. Also, a recording made of a musical ensemble playing all at once, rather than overdubbing.

LOCALIZATION: The ability of the human hearing system to tell the direction of a real or illusionary sound source.

LOOP: In a sampling program, to play the sustain portion of a sound's envelope repeatedly.

LOUDSPEAKER: A transducer that converts electrical energy (the signal) into acoustical energy (sound waves).

LOWPASS FILTER: A filter that passes frequencies below a certain frequency and attenuates frequencies above that same frequency. A high-cut filter.

M: Abbreviation for mega, or one million (as in megabytes).

MAGNETIC RECORDING TAPE: A recording medium made of magnetic particles (usually ferric oxide) suspended in a binder and coated on long strip of thin plastic (usally Mylar).

MASK: To hide or cover up one sound with another sound. To make a sound inaudible by playing another sound along with it.

MASTER FADER: A volume control that affects the level of all program buses simultaneously. It is the last stage of gain adjustment before the 2-track recorder.

MASTER TAPE: A completed tape used to generate tape copies or compact discs.

MD: Abbreviation for MiniDisc.

MDM: Abbreviation for Modular Digital Multitrack.

MEMORY: A group of integrated circuit chips used to store digital data temporarily or permanently (such as an audio signal in digital format).

MEMORY REWIND: A tape-recorder function that rewinds the tape to a preset tape-counter position.

METER: A device that indicates voltage, resistance, current, or signal level.

MIC: An abbreviation for microphone.

MIC LEVEL: The level or voltage of a signal produced by a microphone, typically 2 millivolts.

MIC PREAMP: See Preamplifier.

MICROPHONE: A transducer or device that converts an acoustical signal (sound) into a corresponding electrical signal.

MICROPHONE TECHNIQUES: The selection and placement of microphones to pick up sound sources.

GLOSSARY OF RECORDING TERMS Part 2 of 3 by Bruce Bartlett

MIDI: Abbreviation for Musical Instrument Digital Interface, a specification for a connection between synthesizers, drum machines, and computers that allows them to communicate with and/or control each other.

MIDI CHANNEL: A route for transmitting and receiving MIDI signals. Each channel controls a separate MIDI musical instrument or synth patch. Up to 16 channels can be sent on a single MIDI cable.

MIDI CONTROLLER: A musical performance device (keyboard, drum pads, breath controller, etc.) that outputs a MIDI signal designating note numbers, note on, note off, and so on.

MIDI IN: A connector in a MIDI device that receives MIDI messages.

MIDI INTERFACE: A circuit that plugs into a computer, and converts MIDI data into computer data for storage in memory or on hard disk. The interface also converts computer data into MIDI data.

MIDI OUT--A connector in a MIDI device that transmits MIDI messages.

MIDI THRU--A connector in a MIDI device that duplicates the MIDI information at the MIDI-In connector. Used to connect another MIDI device in the series.

MID-SIDE: A coincident-pair stereo microphone technique using a forward-facing unidirectional, omnidirectional, or bidirectional mic and a side-facing bidirectional mic. The microphone signals are summed and differenced to produce right- and left-channel signals.

MILLI: A prefix meaning one thousandth, abbreviated m.

MIKE: To pick up with a microphone.

MINIDISC (MD): A rewritable, magneto-optical storage medium that is read by a laser. It resembles a compact disc in a 2.5-inch square housing. MD recorders use a data compression scheme called ATRAC.

MIX: 1. To combine two or more different signals into a common signal. 2. A control on a delay unit that varies the ratio between the dry signal and the delayed signal.

MIXDOWN: The process of playing recorded tape tracks through a mixing console and mixing them to two stereo channels for recording on a two-track tape recorder.

MIXER: A device that mixes or combines audio signals and controls the relative levels of the signals.

MIXING CONSOLE: A large mixer with additional functions such as equalization or tone control, pan pots, monitoring controls, solo functions, channel assigns, and control of signals sent to external signal processors.

MODULAR DIGITAL MULTITRACK (MDM): A multitrack tape recorder that records 8 tracks digitally on a videocassette. Several 8-track modules can be connected together to add more tracks in sync. Two examples of MDMs are the Alesis ADAT-XT and TASCAM DA-38.

MONITOR: A loudspeaker in a control room, or headphones, used for judging sound quality. Also, a video display screen used with a computer.

MONITORING: Listening to an audio signal with a monitor.

MONAURAL: Referring to listening with one ear. Often incorrectly used to mean monophonic.

MONO, MONOPHONIC: 1. Referring to a single channel of audio. A monophonic program can be played over one or more loudspeakers, or one or more headphones. 2. Describing a synthesizer that plays only one note at a time (not chords).

MONO-COMPATIBLE: A characteristic of a stereo program, in which the program channels can be combined to a mono program without altering the frequency response or balance. A mono-compatible stereo program has the same frequency response in stereo or mono because there is no delay or phase shift between channels to cause phase interference.

MOVING-COIL MICROPHONE: A dynamic microphone in which the conductor is a coil of wire moving in a fixed magnetic field. The coil is attached to a diaphragm which vibrates when struck with sound waves. Usually called a dynamic microphone.

MP3: MPEG-1 Layer 3, a format for data-compressing an audio file to 1/12 its original size or smaller. Compression at 128 kbps and 44.1K sampling rate is said to be CD quality. Because of their relatively small size, MP3 files can be distributed on the Internet with fairly short upload and download times.

M-S RECORDING: See Mid-side.

MUDDY: Unclear sounding; having excessive leakage, reverberation, or overhang.


MULTIPLE-D MICROPHONE: A directional microphone which has multiple sound-path lengths between its front and rear sound entries. This type of microphone has minimal proximity effect.

MULTIPROCESSOR: A signal processor that can perform several different signal-processing functions.

MULTITIMBRAL--In a synthesizer, the ability to produce two or more different patches or timbres at the same time.

MULTITRACK: Referring to a recorder or tape-recorder head that has more than two tracks.

MUTE: To turn off an input signal on a mixing console by disconnecting the input-module output from channel assign and direct out. During mixdown, the mute function is used to reduce tape noise during silent portions of tracks, or to turn off unused performances. During recording, mute is used to turn off mic signals.

NEAR COINCIDENT: A stereo microphone technique in which two directional microphones are angled apart symmetrically on either side of center and spaced a few inches apart horizontally.

NEAR-FIELD MONITORING: A monitor-speaker arrangement in which the speakers are placed very near the listener (usually just behind the mixing console) to reduce the audibility of control-room acoustics.

NOISE: Unwanted sound, such as hiss from electronics or tape. An audio signal with an irregular, non-periodic waveform.

NOISE GATE: A gate used to reduce or eliminate noise between notes.

NOISE-REDUCTION SYSTEM: A signal processor (Dolby or dbx) used to reduce tape hiss (and sometimes print-through) caused by the recording process. Some of these systems compress the signal during recording and expand it in a complementary fashion during playback.

NON-DESTRUCTIVE EDITING: In a digital audio workstation, editing done by changing pointers (location markers) to information on the hard disk. A non-destructive edit can be undone.

NONLINEAR: 1. Referring to a storage medium in which any data point can be accessed or read almost instantly. Examples are a hard disk, compact disc and MiniDisc. See Random Access. 2. Referring to an audio device that is distorting the signal.

OCTAVE: The interval between any two frequencies where the upper frequency is twice the lower frequency.

OFF-AXIS: Not directly in front of a microphone or loudspeaker.

OFF-AXIS COLORATION: In a microphone, the deviation from the on-axis frequency response that sometimes occurs at angles off the axis of the microphone. The coloration of sound (alteration of tone quality) for sounds arriving off-axis to the microphone.

OMNIDIRECTIONAL MICROPHONE: A microphone that is equally sensitive to sounds arriving from all directions.

ON-LOCATION RECORDING: A recording made outside the studio, in a room or hall where the music usually is performed or practiced.

OPEN TRACKS: On a multitrack tape recorder, tracks that have not yet been used, or have already been bounced and are available for use.

ORTF: Named after the French broadcasting network (Office de Radiodiffusion Television Francaise), a near-coincident stereo mic technique which uses two cardioid mics angled 110 degrees apart and spaced 17 cm horizontally.

OUTBOARD EQUIPMENT: Signal processors that are external to the mixing console.

OUTPUT: A connector in an audio device from which the signal comes, and feeds successive devices.

OUT-TAKE: A take, or section of a take, that is to be removed or not used.

OVERDUB: To record a new musical part on an unused track in synchronization with previously recorded tracks.

OVERHANG: The continuation of a signal at the output of a device after the input signal has ceased. Sometimes called ringing.

OVERLOAD: The distortion that occurs when an applied signal exceeds a system's maximum input level.

OVERTONE: In a complex wave, a frequency component that is higher than the fundamental frequency.

PAD: See Attenuator.

PAN POT: Abbreviation for panoramic potentiometer. In each input module in a mixing console, a control that divides a signal between two channels in an adjustable ratio. By doing so, a pan pot controls the location of a sonic image between a stereo pair of loudspeakers.

PARAMETRIC EQUALIZER: An equalizer with continuously variable parameters, such as frequency, bandwidth, and amount of boost or cut.

PATCH: 1. To connect one piece of audio equipment to another with a cable. 2. A setting of synthesizer parameters to achieve a sound with a certain timbre.

PATCH BAY (PATCH PANEL): An array of connectors, usually in a rack, to which equipment inputs and outputs are wired. A patch bay makes it easy to interconnect various pieces of equipment in a central, accessible location.

PATCH CORD: A short length of cable with a coaxial plug on each end, used for signal routing in a patch bay.

PEAK: On a graph of a sound wave or signal, the highest point in the waveform. The point of greatest voltage or sound pressure in a cycle.

PEAK AMPLITUDE: See Amplitude, Peak.

PEAKING EQUALIZER: An equalizer that provides maximum cut or boost at one frequency, so that the resulting frequency response of a boost resembles a mountain peak.

PEAK PROGRAM METER (PPM): A meter that responds fast enough to closely follow the peak levels in a program.

PERIOD: The time between the peak of one wave and the peak of the next. The time between corresponding points on successive waves. Period is the inverse of frequency.

PERSONAL STUDIO: A minimal group of recording equipment set up for one's personal use, usually using a 4-track cassette recorder-mixer. Also, a simple 4-track cassette recorder-mixer for one's personal use.

PERSPECTIVE: In the reproduction of a recording, the audible sense of distance to the musical ensemble, the point of view. A close perspective has a high ratio of direct sound to reverberant sound; a distant perspective has a low ratio of direct sound to reverberant sound.

PFL: Abbreviation for Pre-Fader Listen. See also Solo.

PHANTOM POWER: A DC voltage (usually 12 to 48 volts) applied to microphone signal conductors to power condenser microphones.

PHASE: The degree of progression in the cycle of a wave, where one complete cycle is 360 degrees.

PHASE CANCELLATION, PHASE INTERFERENCE: The cancellation of certain frequency components of a signal that occurs when the signal is combined with its delayed replica. At certain frequencies, the direct and delayed signals are of equal level and opposite polarity (180 degrees out of phase), and when combined, they cancel out. The result is a comb-filter frequency response having a periodic series of peaks and dips. Phase interference can occur between the signals of two microphones picking up the same source at different distances, or can occur at a microphone picking up both a direct sound and its reflection from a nearby surface.

PHASE SHIFT: The difference in degrees of phase angle between corresponding points on two waves. If one wave is delayed with respect to another, there is a phase shift between them of 2[pi]FT, where [pi] = 3.14, F = frequency in Hz, and T = delay in seconds.

PHASING: A special effect in which a signal is combined with its phase-shifted replica to produce a variable comb-filter effect. See also Flanging.

PHONE PLUG: A cylindrical, co-axial plug (usually 1/4-inch diameter). An unbalanced phone plug has a tip for the hot signal and a sleeve for the shield or ground. A balanced phone plug has a tip for the signal hot signal, a ring for the return signal, and a sleeve for the shield or ground.

PHONO PLUG: A coaxial plug with a central pin for the hot signal and a ring of pressure-fit tabs for the shield or ground. Also called RCA plug.

PICKUP: A piezoelectric transducer that converts mechanical vibrations to an electrical signal. Used in acoustic guitars, acoustic basses, and fiddles. Also, a magnetic transducer in an electric guitar that converts string vibration to a corresponding electrical signal.

PINCH ROLLER: In a tape-recorder transport, the rubber wheel that pinches or traps the tape between itself and the capstan, so that the capstan can move the tape.

PING-PONGING: See Bouncing Tracks.

PINK NOISE: A noise signal containing all frequencies (unless band-limited), with equal energy per octave. Pink noise is a test signal used for equalizing a sound system to the desired frequency response, and for testing loudspeakers.

PITCH: The subjective lowness or highness of a tone. The pitch of a tone usually correlates with the fundamental frequency.

PITCH CONTROL: A control on a tape recorder that varies the tape speed, thereby varying the pitch of the signal on tape. The pitch control can be used to match the pitch of prerecorded instruments with that of an instrument to be overdubbed. It is also used for special effects, such as "chipmunk voices," and to play prerecorded tracks slowly so that fast musical passages can be overdubbed more easily.

PITCH SHIFTER: A signal processor that changes the pitch of an instrument without changing its duration.

PLAYBACK EQUALIZATION: In tape-recorder electronics, fixed equalization applied to the signal during recording to compensate for certain losses.

PLAYBACK HEAD: The head in a tape recorder that picks up a prerecorded magnetic signal from the moving tape and converts it to a corresponding electrical signal. The playback head is not the same as the sel-sync or sync head.

PLAYLIST: See Edit Decision List.

PLUG: A male connector that inserts into a jack.

PLUG-IN: Software effects that you install in your computer. The plug-in software becomes part of another program you are using, such as a digital editing program.

POLAR PATTERN: The directional pickup pattern of a microphone. A plot of microphone sensitivity plotted vs. angle of sound incidence. Examples of polar patterns are omnidirectional, bidirectional, and unidirectional. Subsets of unidirectional are cardioid, supercardioid, and hypercardioid.

POLARITY: Referring to the positive or negative direction of an electrical, acoustical, or magnetic force. Two identical signals in opposite polarity are 180 degrees out-of-phase with each other at all frequencies.

POLYPHONIC--Describing a synthesizer that can play more than one note at a time (chords).

POP: 1. A thump or little explosion sound heard in a vocalist's microphone signal. Pop occurs when the user says words with "p," "t," or "b" so that a turbulent puff of air is forced from the mouth and strikes the microphone diaphragm. 2. A noise heard when a mic is plugged into a monitored channel, or when a switch is flipped.

POP FILTER: A screen placed on a microphone grille that attenuates or filters out pop disturbances before they strike the microphone diaphragm. Usually made of open-cell plastic foam or silk, a pop filter reduces pop and wind noise.

PORTABLE STUDIO: A combination recorder and mixer in one portable chassis.

POST-ECHO: A repetition of a sound, following the original sound, caused by print-through.

POWER AMPLIFIER: An electronic device that amplifies or increases the power level fed into it to a level sufficient to drive a loudspeaker.

POWER GROUND (SAFETY GROUND): A connection to the power company's earth ground through the U-shaped hole in a power outlet. In the power cable of an electronic component with a 3-prong plug, the U-shaped prong is wired to the component's chassis. This wire conducts electricity to power ground if the chassis becomes electrically hot, preventing shocks.

PREAMPLIFIER (PREAMP): In an audio system, the first stage of amplification that boosts a mic-level signal to line level. A preamp is a stand-alone device or a circuit in a mixer.

PREDELAY: Short for pre-reverberation delay. The delay (about 30 to 150 milliseconds) between the arrival of the direct sound and the onset of reverberation. Usually, the longer the predelay, the greater the perceived room size.

PRE-ECHO: A repetition of a sound that occurs before the sound itself, caused by print-through.

PREFADER/POSTFADER SWITCH: A switch that selects a signal either ahead of the fader (prefader) or following the fader (postfader). The level of a prefader signal is independent of the fader position; the level of a postfader signal follows the fader position.

PREPRODUCTION: Planning in advance what you're going to do at a recording session, in terms of track assignments, overdubbing, studio layout, and microphone selection.

PRESENCE: The audible sense that a reproduced instrument is present in the listening room. Some synonyms are closeness, definition, and punch. Presence is often created by an equalization boost in the midrange or upper midrange.

PRESSURE ZONE MICROPHONE: A boundary microphone constructed with the microphone diaphragm parallel with, and facing, a reflective surface.

PREVERB: A special effect in which the reverberation of a note precedes it, rather than follows it. Preverb is achieved by playing an instrument's track backwards while adding reverberation to it, and recording the reverberation on an unused track. When the tape is reversed so that the instrument's track plays forward, preverb is heard as the reverberation plays backwards.

PRINT: To record on tape or disc.

PRINT-THROUGH: The transfer of a magnetic signal from one layer of tape to the next on a reel, causing an echo preceding or following the program.

PRODUCTION: 1. A recording that is enhanced by special effects. 2. The supervision of a recording session to create a satisfactory recording. This involves getting musicians together for the session, making musical suggestions to the musicians to enhance their performance, and making suggestions to the engineer for sound balance and effects.

PROGRAM BUS: A bus or output that feeds an audio program to a recorder track.

PROGRAM MIXER: In a mixing console, a mixer formed of input- module outputs, combining amplifiers, and program buses.

PROXIMITY EFFECT: The bass boost that occurs with a single-D directional microphone when it is placed a few inches from a sound source. The closer the microphone, the greater the low-frequency boost due to proximity effect.

PUNCH IN/OUT: A feature in a multitrack recorder that lets you insert a recording of a corrected musical part into a previously recorded track by going into and out of record mode as the tape is rolling.

PURE WAVEFORM: A waveform of a single frequency; a sine wave. A pure tone is the perceived sound of such a wave.

QUARTER-TRACK: A tape track recorded across one-quarter of the width of the tape. A quarter-track recorder usually records two stereo programs (one in each direction).

RACK: A 19-inch-wide wooden or metal cabinet used to hold audio equipment.

RADIO-FREQUENCY INTERFERENCE (RFI): Radio-frequency electromagnetic waves induced in audio cables or equipment, causing various noises in the audio signal.

RANDOM ACCESS: Referring to a storage medium in which any data point can be accessed or read almost instantly. Examples are a hard disk, compact disc and MiniDisc.

RAREFACTION: The portion of a sound wave in which molecules are spread apart, forming a region with lower-than-normal atmospheric pressure. The opposite of compression.


REAL-TIME RECORDING: 1. Recording notes into a sequencer in the correct tempo, for later playback at the same tempo as recorded. 2. A recording made direct to lacquer disc or direct to 2-track without any overdubs or mixdown.

RECIRCULATION (REGENERATION): Feeding the output of a delay device back into its input to create multiple echoes. Also, the control on a delay device that affects how much delayed signal is recycled to the input.

RECORD: To store an event in permanent form. Usually, to store an audio signal in magnetic form on magnetic tape. Recording is also possible on hard disk, on compact disc (CD-R), on magneto-optical disk, MiniDisc, and in RAM.

RECORD EQUALIZATION: In tape-recorder electronics, equalization applied to the signal during recording to compensate for certain losses.

RECORDER-MIXER: A combination multitrack recorder and mixer in one chassis.

RECORD HEAD: The head in a tape recorder that puts the audio signal on tape by magnetizing the tape particles in a pattern corresponding to the audio signal.

RECORDING/REPRODUCTION CHAIN: The series of events and equipment that are involved in sound recording and playback.

REFLECTED SOUND: Sound waves that reach the listener after being reflected from one or more surfaces.

REGENERATION: See Recirculation.

REGION: In a digital audio editing program, a defined segment of the audio program.

RELEASE: The final portion of a note's envelope in which the note falls from its sustain level back to silence.

RELEASE TIME: In a compressor, the time it takes for the gain to return to normal after the end of a loud passage.

REMIX: To mix again; to do another mixdown with different console settings or different editing.

REMOTE RECORDING: See On-Location Recording.

REMOVABLE HARD DRIVE: A hard disk drive that can be removed and replaced with another, used in a digital audio workstation to store a long program temporarily.

RESISTANCE: The opposition of a circuit to a flow of direct current. Resistance is measured in ohms, abbreviated [Greek Omega], and may be calculated by dividing voltage by current.

RESISTOR: An electronic component that opposes current flow.

RETURN-TO-ZERO: See Memory Rewind.

REVERBERATION: Natural reverberation in a room is a series of multiple sound reflections which makes the original sound persist and gradually die away or decay. These reflections tell the ear that you're listening in a large or hard-surfaced room. For example, reverberation is the sound you hear just after you shout in an empty gymnasium. A reverb effect simulates the sound of a room--a club, auditorium, or concert hall--by generating random multiple echoes that are too numerous and rapid for the ear to resolve. The timing of the echoes is random, and the echoes increase in number with time as they decay. An echo is a discrete repetition of a sound; reverberation is a continuous fade-out of sound.

REVERBERATION TIME (RT60): The time it takes for reverberation to decay to 60 dB below the original steady-state level.

REVERSE ECHO: A multiple echo that precedes the sound that caused it, building up from silence into the original sound. This special effect is created in a manner similar to preverb.

RFI: See Radio Frequency Interference.

RHYTHM TRACKS: The recorded tracks of the rhythm instruments (guitar, bass, drums, and sometimes keyboards).

RIBBON MICROPHONE: A dynamic microphone in which the conductor is a long metallic diaphragm (ribbon) suspended in a magnetic field.

RIDE GAIN: To turn down the volume of a microphone when the source gets louder, and turn up the volume when the source gets quieter, in an attempt to reduce dynamic range.

RINGING: See Overhang.

ROOM MODES: See Standing Wave.

RT60: See Reverberation Time.

SAFETY COPY: A copy of the master tape, to be used if the master tape is lost or damaged.

SAFETY GROUND: See Power Ground.

SAMPLE: 1. To digitally record a short sound event, such as a single note or a musical phrase, into computer memory. 2. A recording of such an event.

SAMPLING: Recording a short sound event into computer memory. The audio signal is converted into digital data representing the signal waveform, and the data is stored in memory chips, tape or disc for later playback.

SATURATION: Overload of magnetic tape. The point at which a further increase in magnetizing force does not cause an increase in magnetization of the tape oxide particles. Distortion is the result.

SCRATCH VOCAL: A vocal performance that is done simultaneously with the rhythm instruments so that the musicians can keep their place in the song and get a feel for the song. Because it contains leakage, the scratch-vocal recording is usually erased. Then the singer overdubs the vocal part that is to be used in the final recording.

SCRUB: To manually move an open-reel tape slowly back and forth across a recorder playback head in order to locate an edit point. Some digital editing software has an equivalent scrubbing function.

SENSITIVITY: 1. The output of a microphone in volts for a given input in sound pressure level. 2. The sound pressure level a loudspeaker produces at one meter when driven with one watt of pink noise. See also Sound Pressure Level.

SEQUENCE: A MIDI data file of musical-performance note parameters, recorded by a sequencer.

SEQUENCER: A device that records a musical performance done on a MIDI controller (in the form of note numbers, note on, note off, etc.) into computer memory or hard disk for later playback. A computer can act as a sequencer when it runs a sequencer program. During playback, the sequencer plays synthesizer sound generators or samples.

SESSION: 1. A time period set aside for recording musical instruments, voices, or sound effects. 2. On a CD-R, a lead-in, program area, and lead-out.

SHELVING EQUALIZER: An equalizer that applies a constant boost or cut above or below a certain frequency, so that the shape of the frequency response resembles a shelf.

SHIELD: A conductive enclosure (usually metallic) around one or more signal conductors, used to keep out electrostatic fields that cause hum or buzz.

SHOCK MOUNT: A suspension system which mechanically isolates a microphone from its stand or boom, preventing the transfer of mechanical vibrations.

SIBILANCE: In a speech recording, excessive frequency components in the 5 to 10 kHz range, which are heard as an overemphasis of "s" and "sh" sounds.

SIDE-ADDRESSED: Referring to a microphone whose main axis of pickup is perpendicular to the side of the microphone. You aim the side of the mic at the sound source. See also End-Addressed.

SIGNAL: A varying electrical voltage that represents information, such as a sound.

SIGNAL PATH: The path a signal travels from input to output in a piece of audio equipment.

SIGNAL PROCESSOR: A device that is used to alter a signal in a controlled way.

SIGNAL-TO-NOISE RATIO (S/N): The ratio in decibels between signal voltage and noise voltage. An audio component with a high S/N has little background noise accompanying the signal; a component with a low S/N is noisy.

SINE WAVE: A wave following the equation y = sin x, where x is degrees and y is voltage or sound pressure level. The waveform of a single frequency. The waveform of a pure tone without harmonics.

SINGLE-ENDED: 1. An unbalanced line. 2. A single-ended noise reduction system is one that works only during tape playback (unlike Dolby or dbx, which work both during recording and playback).

SINGLE-D MICROPHONE: A directional microphone having a single distance between its front and rear sound entries. Such a microphone has proximity effect.

SLAP, SLAPBACK: An echo following the original sound by about 50 to 200 milliseconds, sometimes with multiple repetitions.

SLATE: At the beginning of a recording, a recorded announcement of the name of the tune and its take number. The term is derived from the slate used in the motion-picture industry to identify the production and take number being filmed.

SMPTE TIME CODE: A modulated 1,200 Hz square-wave signal used to synchroinze two or more tape transports or other multitrack recorders. SMPTE is an abbreviation for the Society of Motion Picture and Television Engineers, who developed the time code.

SNAKE: A multipair or multichannel mic cable. Also, a multipair mic cable attached to a connector junction box.

SOLO: On an input module in a mixing console, a switch that lets you monitor that particular input signal by itself. The switch routes only that input signal to the monitor system.

SOUND: Longitudinal vibrations in a medium (such as air) in the frequency range 20 Hz to 20,000 Hz.

SOUND CARD: A circuit card that plugs into a computer, and converts an audio signal into computer data for storage in memory or on hard disk. The sound card also converts computer data into an audio signal.

SOUND MODULE (SOUND GENERATOR): 1. A synthesizer without a keyboard, containing several different timbres or voices. These sounds are triggered or played by MIDI signals from a sequencer program, or by a MIDI controller. 2. An oscillator.

SOUND PRESSURE LEVEL (SPL)--The acoustic pressure of a sound wave, measured in decibels above the threshold of hearing. The higher the SPL of a sound, the louder it is. dB SPL = 20 log (P/P ref), where P = the measured acoustic pressure and P ref = 0.0002 dyne/cm[superscript]2[end superscript]. [ref is subscript]

SOUND WAVE: The periodic variations in sound pressure radiating from a sound source.

SPACED-PAIR: A stereo microphone technique using two identical microphones spaced several feet apart horizontally, usually aiming straight ahead toward the sound source.

SPATIAL PROCESSOR: A signal processor that allows images to be placed beyond the limits of a stereo pair of speakers--even behind the listener or toward the sides.

S/PDIF: Sony Philips Digital Interface (IEC 958 Type II). A digital signal interface format which uses a 75 ohm coaxial cable terminated with RCA or BNC connectors. See also AES/EBU.

SPEAKER: See Loudspeaker.


SPECTRUM: The output versus frequency of a sound source, including the fundamental frequency and overtones.

SPL: See Sound Pressure Level.

SPLICE: To join the ends of two lengths of magnetic tape or leader tape with tape. Also, a splice is the taped joint between two lengths of magnetic tape or leader tape.

SPLICING BLOCK: See Editing Block.

SPLIT CONSOLE: A console with a separate monitor-mixer section. See also In-Line Console.

SPLITTER: A transformer or circuit used to divide a microphone signal into two or more identical signals to feed different sound systems.

SPOT MICROPHONE: In classical music recording, a close-placed microphone that is mixed with more-distant microphones to add presence or to improve the balance.

STANDING WAVE: An apparently stationary waveform, created by multiple reflections between opposite room surfaces. At certain points along the standing wave, the direct and reflected waves cancel, and at other points the waves add together or reinforce each other.

STEP-TIME RECORDING: Recording notes into a sequencer one at a time without regard to tempo, for later playback at a normal tempo.

STEREO, STEREOPHONIC--An audio recording and reproduction system with correlated information between two channels (usually discrete channels), and meant to be heard over two or more loudspeakers to give the illusion of sound-source localization and depth.

STEREO BAR, STEREO MICROPHONE ADAPTER: A microphone stand adapter that mounts two microphones on a single stand for convenient stereo miking.

STEREO IMAGING: The ability of a stereo recording or reproduction system to form clearly defined audio images at various locations between a stereo pair of loudspeakers.

STEREO MICROPHONE: A microphone containing two mic capsules in a single housing for convenient stereo recording. The capsules usually are coincident.

STUDIO: A room used or designed for sound recording.

SUBMASTER: 1. A master volume control for an output bus. 2. A recorded tape that is used to form a master tape.

SUBMIX: A small preset mix within a larger mix, such as a drum mix, keyboard mix, vocal mix, etc. Also a cue mix, monitor mix, or effects mix.

SUBMIXER--A smaller mixer within a mixing console (or stand-alone) that is used to set up a submix, a cue mix, an effects mix, or a monitor mix.

SUPERCARDIOID MICROPHONE: A unidirectional microphone that attenuates side-arriving sounds by 8.7 dB, attenuates rear- arriving sounds by 11.4 dB, and has two nulls of maximum sound rejection at 125 degrees off-axis.

SUPPLY REEL: See Feed Reel.

SURROUND SOUND: A multichannel recording and reproduction system that plays sound all around the listener. The 5.1 surround system uses the following speakers: front-left, center, front-right, left-surround, right-surround, and subwoofer.

SUSTAIN: The portion of the envelope of a note in which the level is constant. Also, the ability of a note to continue without noticeably decaying, often aided by compression.

SWEETENING: The addition of strings, brass, chorus, etc. to a previously recorded tape of the basic rhythm tracks.

SYNC, SYNCHRONIZATION: Aligning two separate audio programs in time, and maintaining that alignment as the programs play.

SYNC, SYNCHRONOUS RECORDING: Using a record head temporarily as a playback head during an overdub session, to keep the overdubbed parts in synchronization with the recorded tracks.

SYNC TONE: See Tape Sync.

SYNC TRACK: A track of a multitrack recorder that is reserved for recording an FSK sync tone or SMPTE time code. This allows audio tracks to synchronize with virtual tracks recorded with a sequencer. A sync track also can synchronize two audio tape machines or an audio recorder and a video recorder, and can be used for console automation.

SYNTHESIZER: A musical instrument (usually with a piano-style keyboard) that creates sounds electronically, and allows control of the sound parameters to simulate a variety of conventional or unique instruments.

TAIL-OUT: Referring to a reel of tape wound with the end of the program toward the outside of the reel. Tape stored tail out is less likely to have audible print-through.

TAKE: A recorded performance of a song. Usually, several takes are done of the same song, and the best one--or the best parts of several--become the final product.

TAKE SHEET: A list of take numbers for each song, plus comments on each take.

TAKE-UP REEL: The right-side reel on a tape recorder that winds up the tape as it is playing or recording.

TALKBACK: An intercom in the mixing console for the engineer and producer to talk to the musicians in the studio.

TAPE: See Magnetic Recording Tape.

TAPE LOOP: An endless loop formed from a length of recording tape spliced end-to-end, used for continuous repetition of several seconds of recorded signal.

TAPE RECORDER: A device that converts an electrical audio signal into a magnetic audio signal on magnetic tape, and vice versa. A tape recorder includes electronics, heads, and a transport to move the tape.

TAPE SYNC: A frequency-modulated signal recorded on a tape track, used to synchronize a tape recorder to a sequencer. Tape sync also permits the synchronized transfer of sequences to tape. See also Sync Track.

3-PIN CONNECTOR: A 3-pin professional audio connector used for balanced signals. Pin 1 is soldered to the cable shield, pin 2 is soldered to the signal hot lead, and pin 3 is soldered to the signal return lead. See also XLR-Type Connector.

THREE-TO-ONE RULE: A rule in microphone applications. When multiple mics are mixed to the same channel, the distance between mics should be at least three times the distance from each mic to its sound source. This prevents audible phase interference.

THRESHOLD: In a compressor or limiter, the input level above which compression or limiting takes place. In an expander, the input level below which expansion takes place.

TIE: To connect electrically, for example, by soldering a wire between two points in a circuit.

TIGHT: 1. Having very little leakage or room reflections in the sound pickup. 2. Referring to well-synchronized playing of musical instruments. 3. Having a well-damped, rapid decay.

TIMBRE: The subjective impression of spectrum and envelope. The quality of a sound that allows us to differentiate it from other sounds. For example, if you hear a trumpet, piano, and a drum, each has a different timbre or tone quality that identifies it as a particular instrument.

TIME CODE: A modulated 1200-Hz square-wave signal used to synchronize two or more tape or disc transports. See also Tape Sync, Sync Track, SMPTE.

TONAL BALANCE: The balance or volume relationships among different regions of the frequency spectrum, such as bass, midbass, midrange, upper midrange, and highs.

GLOSSARY OF RECORDING TERMS Part 3 of 3 By Bruce Bartlett

TRACK: A path on magnetic tape containing a single channel of audio. A group of bytes in a digital signal (on tape, on hard disk, on compact disc, or in a data stream) that represents a single channel of audio or MIDI. Usually one track contains a performance of one musical instrument.

TRANSDUCER: A device that converts energy from one form to another, such as a microphone or loudspeaker.

TRANSFORMER: An electronic component made of two magnetically coupled coils of wire. The input signal is transferred magnetically to the output, without a direct connection between input and output.

TRANSIENT: A short signal with a rapid attack and decay, such as a drum stroke, cymbal hit, or acoustic-guitar pluck.

TRANSIENT RESPONSE: The ability of an audio component (usually a microphone or loudspeaker) to follow a transient accurately.

TRANSPORT: The mechanical system in a reproduction device that moves the media past the read/write heads. In a tape recorder, the transport controls tape motion during recording, playback, fast forward, and rewind.

TRIM: 1. In a mixing console, a control for fine adjustment of level, as in a Bus Trim control. 2. In a mixing console, a control that adjusts the gain of a mic preamp to accommodate various signal levels.

TUBE: A vacuum tube, an amplifying component made of electrodes in an evacuated glass tube. Tube sound is characterized as being "warmer" than solid-state or transistor sound.

TWEETER: A high-frequency loudspeaker.

UNBALANCED LINE: An audio cable having one conductor surrounded by a shield that carries the return signal. The shield is at ground potential.

UNIDIRECTIONAL MICROPHONE: A microphone that is most sensitive to sounds arriving from one direction -- in front of the microphone. Examples are cardioid, supercardioid, and hypercardioid.

VALVE: British term for vacuum tube. See Tube.

VIRTUAL CONTROLS: Audio-equipment controls that are simulated on a computer monitor screen. You adjust them with a mouse.

VIRTUAL TRACK: A sequencer recording of a single musical line, recorded as data in computer memory. A virtual track is the computer's equivalent of a tape track on a multitrack tape recorder.

VU METER: A voltmeter with a specified transient response, calibrated in VU or volume units, used to show the relative volume of various audio signals, and to set recording level.

WAVEFORM: A graph of a signal's sound pressure or voltage versus time. The waveform of a pure tone is a sine wave.

WAVELENGTH: The physical length between corresponding points of successive waves. Low frequencies have long wavelengths; high frequencies have short wavelengths.

WEBER: A unit of magnetic flux.

WEIGHTED: Referring to a measurement made through a filter with a specified frequency response. An A-weighted measurement is taken through a filter that simulates the frequency response of the human ear.

WINDSCREEN: See Pop Filter.

WOOFER: A low-frequency loudspeaker.

WORKSTATION: A system of MIDI- or computer-related equipment that works together to help you compose and record music. Usually, this system is small enough to fit on a desktop or equipment stand. See also Keyboard Workstation and Digital Audio Workstation.

WOW: A slow periodic variation in tape speed.

XLR-TYPE CONNECTOR: An ITT Cannon part number which has become the popular definition for a 3-pin professional audio connector. See also Three-Pin (3-Pin) Connector.

XMIDI: Extended MIDI, a proposed compatible upgrade to MIDI with enhanced features and capabilities, and more functions.

X-Y: See Coincident-Pair.

Y-ADAPTER: A cable that divides into two cables in parallel to feed one signal to two destinations.

Z: Abbreviation for impedance.

ZONE: See Region.

Copyrighted 1999 by Deltamedia. May not be reproduced in whole or part without permission.