REMIX RESOURCES GLOSSARY OF MUSICAL AND AUDIO TERMS
These glossary terms come courtesy of Moog Music(www.moogmusic.com) in its Little Phatty user manual, and Thomson Course Technology (www.thomson.com) in its Mixing Engineer's Handbook: Second Edition, written by Bobby Owinski.
5.1 - A speaker system that uses three speakers across the front and two stereo speakers in the rear, along with a subwoofer.
ambience - The background noise of an environment.
amplitude - The strength of a sound's vibration measured in decibels (dB). Amplitude corresponds to the musical term "loudness."
attack - The first part of a sound, or, on a compressor/limiter, this is a control that affects how that device will respond to the attack of a sound.
attenuation - A decrease in level.
Augspurger - George Augspurger of Perception Inc. in Los Angeles is one of the most revered studio designers. He also designs large monitors, each having dual 15-inch woofers and a horn tweeter.
bandwidth - The number of frequencies that a device will pass before the signal degrades. A human being can supposedly hear from 20Hz to 20kHz, so the bandwidth of a human ear is 20Hz to 20kHz.
bass management - A circuit that utilizes the subwoofer in a 5.1 system to provide bass extension for the five main speakers. The bass manager steers all frequencies below 80Hz into the subwoofer, along with the LFE source signal. (See also "LFE.")
bass redirection - Another term for bass management.
bit rate - The transmission rate of a digital system.
bus (or buss) - A signal pathway.
chamber (reverb) - A method to create artificial reverberation using a tiled room with a speaker and several microphones placed in a room.
chorus - A type of signal processor in which a detuned copy is mixed with the original signal, creating a fatter sound.
codec - Compressor/decompressor. A codec is a software algorithm that encodes and decodes a particular file format. WAV, AIFF and MP3 are examples of codecs.
comb filter - A distortion produced by combining an electronic or acoustic signal with a delayed copy of itself. This results in peaks and dips introduced into the frequency response. This is what happens when a signal is flanged. (See also "flanging.")
competitive level - A mix level that is as loud as your competitor's mix.
control voltage - Control voltages (also called CVs) are used in analog synthesizers to affect changes in the sound. In the case of pitch, pressing a key on the keyboard sends a control voltage that determines the pitch of the oscillators. The keyboard CV is set to produce an equal tempered scale. As you play up the keyboard, the CV is raised, and the pitch increases. The pitch can also be affected by other CV sources, like an LFO, often used to produce vibrato. Other major synthesizer components that respond to CVs include the filter (the higher the CV, the higher the filter cutoff frequency) and the amplifier (the higher the CV, the higher the gain, or volume).
controller - An external hardware device that controls the parameters of a computer application.
cut - To decrease, attenuate or make less.
cut pass - A playback of a song in which the engineer programs only the mutes into the automation to clean up the mix.
data compression - A method of taking multiple digital data streams (as in 6-channel surround sound) and combining them into a single data stream for more efficient storage or transmission.
DAW - Digital audio workstation. A computer with the appropriate hardware and software needed to digitize and edit audio.
DDL - Digital delay line. This is the same as a digital delay. (See also "delay.")
decay - The time is takes for a signal to fall below audibility.
delay - A type of signal processor that produces distinct repeats (echoes) of a signal.
Distressor - A compressor made by Empirical Labs that's noted for its distinctively aggressive sound.
Dolby Digital - A data compression method, otherwise known as AC-3, that uses psycho-acoustic principles to reduce the number of bits required to represent the signal. Bit rates for 5.1 channels range from 320 kbps for sound on film to 384 kbps for digital television and up to 448 kbps for audio use on DVD. AC-3 is also what's known as a lossy compressor that relies on psycho-acoustic modeling of frequency and temporal masking effects to reduce bits by eliminating those parts of the signal thought to be inaudible. The bit rate reduction achieved at a nominal 384 kbps is about 10 to 1. (See also "lossy compression.")
documentation - The session notes and track sheets for a song.
downmix - To automatically extract a stereo or mono mix from an encoded surround mix.
DTS - A data compression method developed by Digital Theater Systems using waveform coding techniques. It takes six channels of audio (5.1) and folds them into a single digital bit stream. This differs from Dolby Digital in that the data rate is a somewhat higher 1.4Mbps, which represents a compression ratio of about 4 to 1. DTS is also known as a lossy compression. (See also "lossy compression.")
DTV - Digital television.
element - A component or ingredient of the sound or groove.
elliptical EQ - A special equalizer built especially for vinyl disc mastering that takes excessive bass energy from either side of a stereo signal that directs it to the center. This prevents excessive low-frequency energy from cutting through the groove wall and destroying the master lacquer.
envelope - An envelope describes the contours that affect the characteristics of a sound (pitch, tone and volume) over time. For example, when a string is plucked, its amplitude is suddenly very loud, but then dies out gradually. This describes the volume envelope of the sound. Also, the initial part of the plucked sound is very bright, but then the brightness fades away. This describes the tonal envelope contour. Finally, the frequency of the sound is heard going slightly higher when the string is plucked, and then dropping slightly as the note fades. This is the pitch envelope contour. A synthesizer can create these kinds of changes by applying electrically generated envelopes to oscillators (affecting pitch), filter (affecting tone) and amplifiers (affecting volume).
envelope generator - A circuit that generates an envelope signal. The envelope generator creates a time-varying signal that can be applied to any voltage-controlled circuit. The envelope generators in many analog synthesizers have four adjustable segments: attack, decay, sustain and release, also sometimes referred to as ADSR. The attack, decay and release segments are specified as time parameters, while the sustain segment is simply a level setting. Attack specifies the onset time of the envelope. For example, the sound of a plucked string starts suddenly, meaning its volume envelope has a fast attack time. Decay specifies how quickly the onset of the envelope fades into the sustained portion. Sustain is the level at which the envelope sustains after the initial transient (the attack and decay portion). Finally, release determines how long the envelope takes to fade away. An envelope generator uses a trigger to start and stop the ADSR envelope. This trigger is called the gate signal, and it's produced whenever a key is pressed on the keyboard. The gate signal turns on and stays on as long as a key is held down. When the key is released, the gate signal turns off. When the gate is on, the envelope generator is triggered, and the envelope signal moves through the attack and decay segments and settles at the sustain level as long as the gate signal is on. When the gate goes off, the release segment of the envelope begins. A new gate signal retriggers the envelope generator.
equalizer - A tone control that can vary in sophistication from very simple to very complex. (See also "parametric equalizer.")
exciter - An outboard effects device that uses phase manipulation and harmonic distortion to produce high-frequency enhancement of a signal.
filter - A circuit that removes some frequencies and allows other frequencies to pass through the circuit. A filter has a cutoff frequency that determines the point at which frequencies begin to be removed. A lowpass filter is one in which frequencies above the cutoff frequency are removed, and all frequencies below the cutoff are passed through. A highpass filter is one in which frequencies below the cutoff frequency are removed and frequencies above the cutoff are passed through. A bandpass filter has two cutoff frequencies that define a frequency band, outside of which the frequencies are removed.
flanging - The process of mixing a copy of the signal back with itself, but gradually and randomly slowing down the copy to cause the sound to "whoosh" as if it were in a wind tunnel. This was originally down by holding a finger against a tape flange (the metal part that holds the tape on the reel), hence the name.
Fletcher-Munson curves - A set of measurements that describes how the frequency response of the ear changes at different sound pressure levels. For instance, people generally hear very high and very low frequencies much better as the overall sound pressure level is increased.
frequency - The rate of vibration in sound measured in Hertz (Hz or cycles per second). The average hearing range of the human ear is from 20 to 20,000 Hz. Frequency corresponds to the musical term "pitch," but the two terms are not always interchangeable. Frequency is an objective measurement of sound, while pitch is the perception of a sound, low, high or mid-ranged. A low frequency corresponds to a low-pitched sound such as bass; a high frequency sound corresponds to a high-pitched sound such as piccolo. In music, a change in pitch of one octave higher equals a doubling of the frequency.
frequency modulation - Also known as FM, frequency modulation describes the technique of using one oscillator to modulate the frequency of another. In FM, the modulation oscillator is called the modulator, while the other oscillator is known as the carrier. The carrier oscillator is the one you hear. When the modulator frequency is very low (about 6 Hz), the effect is described as vibrato. As the modulator frequency is raised into the audio range, new modulation frequency components are created, and the effect is perceived as adding new overtones to the carrier signal.
glide - Also called portamento, is the slowing down of pitch changes as you play different notes on the keyboard. Certain acoustic instruments, like the trombone or the violin, create this effect when the performer adjusts the tubing or string length. The speed of the glide is the glide rate. In synthesizers, glide rate control determines how the speed of the glide varies between notes.
groove - The pulse of the song and the way the instruments dynamically breathe with it.
harmonic - A sound is made up of simple vibrations at many different frequencies (called harmonics) that give a sound its particular character. This corresponds to the musical term "timbre" or "tone color." A harmonic sound, such as a vibrating string, is one in which the harmonics are mathematically related by what is called the harmonic series. These sounds are typically pleasing to the ear, and generally the consecutive vibrations have the same characteristic shape or waveform. An inharmonic sound, such as a crash cymbal, is one in which the harmonics are not mathematically related. Their waveforms look chaotic. White noise is an inharmonic sound that contains equal amounts of all frequencies.
harmonizer - Originally developed and trademarked by Eventide, the harmonizer has become a generic term for pitch shifting, either to tune an instrument (usually a vocal) or as an effect similar to chorusing.
headroom - The amount of dynamic range between the normal operating level and the maximum output level, which is usually the onset of clipping.
highpass filter - A filter that allows only the high frequencies to pass. The frequency point where it cuts off is usually either switchable or variable.
hypercompression - Adding too much compression to a track, leaving it sounding lifeless and unexciting.
LFE - Low-frequency effects channel. This a special channel of 5 to 120 Hz information primarily intended for special effects such as explosions in movies. The LFE has an additional 10 dB of headroom to accommodate the required level.
lossy compression - A data compression method that uses psychoacoustic principles to reduce the number of bits required to represent the signal. Lossy compression relies on psychoacoustic modeling of frequency and temporal masking effects to reduce bits by eliminating those parts of the signal thought to be inaudible.
low freqeuncy oscillator - Also called an LFO, this is a special type of oscillator that generate signals primarily below the range of human hearing (generally below 20 Hz). LFOs are typically used as a source of modulation. For instance, an LFO with a triangle waveform, set to about 6 Hz and modulating the pitch of a VCO results in vibrato. Changing the LFO waveform to a square wave will result in a trill. An LFO modulating a VCA with a triangle wave creates tremolo.
lowpass filter - A filter that allows only the low frequencies to pass. The frequency point where it cuts off is usually either switchable or variable.
make-up gain - A control on a compressor/limiter that applies additional gain to the signal. This is required because the signal automatically decreases when the compressor is working. Make-up gain "makes up" the gain and brings it back to where it was prior to compression.
mastering - The process of turning a collection of songs into a record by making them sound like they belong together in tone, volume and timing (spacing between songs).
mixer - In synthesizers, a circuit for combining multiple sound sources or signals.
MLP - Meridian lossless packing. This is a data compression technique designed specifically for high-quality (24-bit/96 kHz) sonic data. MLP differs from other data compression techniques in that no significant data is thrown away, thereby claiming the "lossless" moniker. MLP is also a standard for the 24-bit/96 kHz portion of a DVD-Audio disc.
modulation - The process of adding a control voltage to a signal source to change its character or tone. For example, modulating a short slap delay with a 0.5 Hz signal produces chorusing. Modulation has a source, a destination and an amount. This could be as simple as the filter cutoff of a VCF (the modulation destination) being changed by a keyboard's filter cutoff control (the source), or as complex as mixing multiple CVs together to modulate filter cutoff. Modulation is used in synthesis to create complex sounds and add variation.
mute - A parameter or control that temporarily silences the audio.
oscillator - A circuit that electronically "vibrates." When used as a sound source, an oscillator is the electronic equivalent of a vibrating reed, or string. When amplified, an oscillator produces a pitched sound whose frequency is determined by one or more control voltages. Changes to these voltages correspond to changes in pitch. An oscillator's vibrations can have different shapes or waveforms, such as a triangle, sawtooth or square wave.
overdubbing - The process of recording new material while listening to material that has been previously recorded. (See also "Selsync.")
parametric equalizer - A tone control in which the gain, frequency and bandwidth are variable.
pan pot - Short for pan potentiometer, which is the electronic name for the hardware control on a recording console that set the audio panning.
phantom image - The effect in a stereo system whereby, if the signal is of equal strength in the left and right channels, the resultant sound appears to come from between them.
phase shift - The highly undesirable process during which some frequencies (usually those below 100 Hz) are slowed down ever so slightly as they pass through a device. This is usually exaggerated by excessive use of equalization.
pitch - The subjective perception of sound. A bass guitar generates low pitches, while a flute generates high pitches.
plate (reverb) - A method to create artificial reverberation using a large steel plate with a speaker and several transducers attached directly to it.
pole - A term referring to the design of a filter circuit. Each filter pole adds 6 dB/octave of attenuation to the filter response, so while a single pole filter has a 6 dB/octave response, a 4-pole filter has a 24 dB/octave response.
predelay - A variable length of time before the onset of reverberation. Mixing engineers often use predelay to separate the source from the reverberation, so they can hear the source more clearly.
Prologic - Dolby's sophisticated algorithm that processes stereo material to reproduce 4- or 5-channel surround sound.
Pultec - An equalizer that Western Electric sold during the '50s and '60s that is highly prized today for its smooth sound.
punchy - A description for a quality of sound that infers good reproduction of dynamics with a strong impact. The term sometimes means emphasis in the 200 Hz and 5 kHz areas.
Q - Bandwidth of a filter or equalizer. (See also "bandwidth.")
ratio - A control on a compressor/limiter that determines how much compression or limiting will occur when the signal exceeds threshold.
range - On a gate or expander, a control that adjusts the amount of attenuation that will occur to the signal when the gate is closed.
recall - A system that memorizes the position of all controls and switches on a console. The engineer must still physically reset the pots and switches back to their previous positions as indicated on a video monitor.
release - The last part of a sound, or, on a compressor/limiter, this is a control that affects the way that device responds to the release of a sound.
return - Inputs on a recording console especially dedicated for effects devices such as reverbs and delays. The return inputs are usually not as sophisticated as normal channel inputs on a console.
reverb - A type of signal processor that reproduces that spatial sound of an environment (that is, the sound of a closet or locker room or inside an oil tanker).
SDDS - Sony Dynamic Digital Sound. This is Sony's digital delivery system for the cinema. The 7.1 system features five speakers across the front, stereo speakers on the sides and a subwoofer.
Selsync - Selective synchronization. This is the process of using the record head on a tape machine to do simultaneous playback of previously recorded tracks while recording. This process is now called overdubbing.
sibilance - A rise in the frequency response in a vocal in which the 5 kHz is excessive, resulting in an overemphasis in S sounds.
slate - A comment added to a tape or track to identify it. In the early days of tape, a 50 Hz slate tone was added before each take of a song to easily identify its beginning as the tape was rewinding.
sound - Audible vibrations of air pressure. For electronic sounds such as those produced by a synthesizer, loudspeakers are used to translate the electrical vibrations into the changes in air pressure that are perceived as sound.
Spatializer - A process developed by Spatializer Laboratories that uses psychoacoustic algorithms to give the listener the impression that he is immersed in sound.
SPL - Sound pressure level.
sub - Subwoofer.
subtractive synthesis - A method of creating tones using harmonically rich (bright) source material and then removing (or in some cases emphasizing) various frequency components to create the desired sound.
subwoofer - A low-frequency speaker that has a frequency response from about 25 Hz to 120 Hz.
synchronization - The condition by which two devices--usually storage devices such as tape machines, DAWs or sequencers--are locked together in respect to time.
synthesis - The generation of sound by electronic means, where programmer/performer has the ability to change the pitch, volume, timbre and articulation.
tape slap - A method to create a delay effect by using the repro head of a tape machine (which is located after the record head in the tape patch).
test tones - A set of tones used to calibrate a playback system. In the days of tape, they were added to a tape to help calibrate the playback machine.
threshold - The point at which an effect takes place, or, on a compressor/limiter, for instance, this is the control that adjusts the point at which compression will take place.
timbre - Pronounced "tamber," it refers to the quality of a sound by its overtones. An unprocessed sawtooth wave has a bright timbre, while a triangle wave has a mellow timbre.
track sharing - The condition by which a single track shares more than one instrument. For instance, this might happen when a percussion part is playing on a guitar solo track in the places where the guitar has not been recorded. This is usually used when the number of available tracks is limited.
tremolo - Technically a form of low frequency amplitude modulation, tremolo is a smooth audible pulsing of volume. In synthesizers, tremolo is produced when a 5-6 Hz LFO triangle or sine wave is applied to a voltage controlled amplifier.
TV mix - A mix without the vocals so that the artist can sing live to the back tracks during a television appearance.
unity gain - When the output level of a process or processor exactly matches its input level.
varispeed - A parameter on tape recorders that varies the speed of playback.
VCA - Voltage controlled amplifier. A VCA is an amplifier circuit where the gain is a function of the control voltage. In analog synthesizers, the VCA is often pared with the volume ADSR envelope generator to specify the articulation of sound.
VCF - Voltage controlled filter. A VCF is a filter circuit where the filter cutoff frequency is a function of the control voltage. A VCF is used to control the timbre of a sound. In analog synthesizers, the VCF is often paired with the filter ADSR envelope generator for dynamic control.
VCO - Voltage controlled oscillator. A VCO is an oscillator circuit where the oscillator frequency is a function of the control voltage. In analog synthesizer keyboard, the VCO is primarily controlled from the keyboard.
vibrato - Technically a very low frequency modulation, vibrato is a smooth, mild pitch warble. In synthesizers, vibrato is produced when a 5-6 Hz LFO triangle or sine wave signal is applied to a voltage controlled oscillator, causing the pitch to deviate slightly above and below the base frequency.
Vocal Stressor - A signal processor made by the now-defunct ADR company that combined a compressor, EQ and de-esser, all tuned in such a way as to make a vocal stand out in the mix.
waveform - The shape of an oscillator's vibration. This determines its timbre. Commonly used waveforms in subtractive synthesis are sawtooth, triangle, square or rectangular. Different waveforms have different timbres. A sawtooth has the greatest number of harmonics and sounds bright and buzzy. A square wave has only odd harmonics and sounds bright, but hollow, like a clarinet. A rectangular wave can vary in shape, but typically has a bright but thin sound, and a triangle wave's harmonics are so low in amplitude that it sounds muted and flute-like.