Definitions Rack to Run Off


A cabinet of standard width (19″) into which various components can be bolted. Racks are ideal for touring equipment, are neat, and they allow easy access to the rear and front panels.

Rack Ears (Rack Flanges)
Mounting brackets that can be attached to equipment to make the equipment able to be housed in a standard equipment rack.

Rack Mount
To mount in an equipment rack.

Rack Space
A standardized size of the front mounting plate in outboard gear equal to approximately 1 3/4″ tall by 19″ wide.

Rack Toms
Small to medium-size drums (usually 10 – 14 inch diameter) that are mounted to a rack over the foot drum in a drum kit.

The angle and pattern of coverage of a speaker.

Radiation Pattern
A drawing of the coverage of speaker using a polar graph.

Radio Frequencies
Frequencies higher than 20,000 Hz (usually above 100 kHz).

Radio Mic
Device consisting of a microphone head, transmitter pack with batteries, aerial and mains receiver unit which allows actors and singers to be amplified with no visible means of connection. Almost universally used in musicals where the singers have to be amplified to be heard over the orchestra/band. Used in non-musical shows for sound reinforcement.

Shortened from the first letters of Random Access Memory (memory stored in the computer and immediately available for use and updating).

Ramp Wave
A waveform that is similar to a sawtooth waveform but different in that it starts at zero level and gradually rises to its peak level and then instantly drops back to zero level to form one cycle.

Random Access Memory
Memory stored in the computer and immediately available for use and updating.

Random Note Generator
A device that generates unpredictable pitches at a set rate, used in synthesizers.

Random Phase
The presence of many signals (or reflections) where some of the signals are in phase and some out of phase and overall having the effect of being between in-phase and out-of-phase.

To perform a spoken rhythmic part to a music or percussion performance.

The air particles being spread apart in the formation of a sound pressure wave.

Rated Load Impedance
The input impedance (opposition to current flow by an input of a device) that a piece of equipment is designed to feed.

RCA Plug (jack)
The common audio connector found on most stereo systems.

Short for the name Rotating Head Digital Audio Tape, a standard format of recording digital audio on a very small tape cassette, using a rotating head.

Opposition to the flow of electrical current which changes with the frequency of the current.

The retrieval of information bits from a storage device; equivalent to reproduction of digital signals.

Read Head
The digital audio reproduce head in a digital recorder or a similar device that converts magnetic pulses on a storage medium to voltage pulses.

Read Only Memory
A memory IC that has digital data on it that cannot be erased/rewritten by the user.

A control state of one track of a multitrack tape recorder where the track will go into record when the record function of the tape recorder is activated.

To be able to take in and respond to (incoming digital control data).

The switch, which activates the electronics of the tape, machine to record.

Record Calibration Control
A tape machine electronics’ control that matches the signal level monitored in the input position of the output selector switch to that of the signal recorded and played back from the tape.

Record Equalization
The increase in amplitude of signals, in a tape machine’s electronics, at the high frequencies as a tape is recorded to keep high-frequency signals recorded above the tape noise.

Record Head
A device that changes electrical current to magnetic energy; the changes of the magnetism match the wave shape of the audio signal fed to the head.

Record Level
A control, which determines the amount of magnetic flux recorded on the tape.

Record Monitor
On some tape machines, the switch position on the electronics which allows the VU meter and sound output of the tape machine electronics to monitor the input signal to the tape machine.

Record Ready
A control state of one track of a multitrack tape recorder where the track will go into record when the record function of the tape recorder is activated.

Recording Buss
A Buss (a wire carrying signals fed from several sources to a destination) that sends mixed signals from the console channels to the multitrack recorder.

Recording Chain
All of transducers and changes of energy form in a recording and reproducing system, listed in order.
Recording Group Another term for Recording Buss or the signals present on the buss.

Recording Session
Any period where music is being recorded, especially the first such period where the rhythm instruments are being recorded.

Recording Solo
A switch (or function) where the signal of a channel is routed to the monitor system by itself, yet the signals out of the console to the recorder are not interrupted.

A person operating recording equipment as a hobby or non-professionally.

1) The hub and flanges that hold tape and which tape can be spooled onto or off of.
2) The amount of tape that fits on a Reel (definition 1).

Reel Lock
The device that secures the reel to the turntable in a transport.

Reel Motor
The motor that turns the platter holding the reel on a tape transport.

Reference Level
1) A standard value used to describe how much level is present in dB above or below this reference.
2) A term with the same meaning as the term Operating Level (the maximum average level that should not be exceeded in normal operation).

Reference Tones
A term with the same meaning as the term Test Tones (a recording of several single-frequency tones at the beginning of a tape reel at the magnetic reference level that will be used to record the program).

Reflected Sound
Sound that reaches a microphone or listener after one or more reflections from surrounding surfaces.

1) A term with the same meaning as the term Jam Sync (a generation of a new SMPTE time code signal according to the input SMPTE signal, giving an identical SMPTE signal out as came in).
2) Feedback, especially around a delay line.

A user modified program (with changed parameters) which is stored in the memory of an effects unit, or sound module.

Regulated Power Supply
A device to supply power to electronic equipment whose output voltage will not fluctuate when more equipment is turned on, or if there is a change in voltage of the power line.

An electric switch, when a control voltage is applied to the device, two terminals are connected (or disconnected).

Relay Rack
An older term for the term Equipment Rack, a cabinet with rails (or free standing rails) that have holes to accept screws at standard spaces and used to house outboard gear.

The rate that the volume of a synthesizer drops to no-sound once the key is released.

Release Time
The time it takes for a dynamics processing device to change gain when the input signal crosses the threshold level while decreasing.

Opposition to the flow of magnetism.

A mixing engineer who specializes in Re-mixing (the mixdown of other versions of a song, often adding additional parts and/or samples).

1) A seldom-used alternate term meaning the same thing as the term Mixdown (combining the signals from the tracks of a multitrack tape onto a two track master tape).
2) The mixdown of other versions of a song, often adding additional parts and/or samples.

1) The controls that will control a tape machine with the operator at a distance from the machine.
2) The recording at the sight of a performance rather than in a recording studio.

Repeat Echo
An echo effect caused by discrete repeats of a program source by using a long delay time and feedback on a delay line. Also called Space Echo.

Replacement Dialogue
Dialogue recorded for a film after the film is shot to replace poorly recorded dialogue, or to change dialogue text.

Residual Magnetization
The amount of magnetism left in a magnetic material after the magnetizing force is removed.

Residual Noise
The noise level left on recording tape after it has been erased.

1) That property of a conductor by which it opposes the flow of electric current, resulting in the generation of heat in the conducting material, usually expressed in ohms.
2) Opposition to the flow of current in one direction or which does not represent different opposition for signals of different frequencies.

1) A device used in a circuit primarily to provide resistance.
2) A device which opposes the flow of electrical current and does so evenly at all frequencies.

1) The effect produced when the natural vibration frequency of a body is greatly amplified by reinforcing vibrations at the same or nearly the same frequency from another body.
2) The prolonging of the sound at a certain frequency and the tendency of something to vibrate at a particular frequency after the source of energy is removed.

1) Tending to pass signals of a certain frequency or narrow range of frequencies more than signals of other frequencies.
2) Physical properties that tend to reinforce the energy at certain frequencies of vibration.

Resonant Frequency
The frequency at which a physical item tends to vibrate after the source of energy (causing the vibration) is removed.

1) To vibrate at the resonant frequency.
2) To linger on, as in reverberation, said of sound in a room or used to describe a room/area that has reverberation with a long reverb time.

Short for the term Echo Return or Auxiliary Return (the input of the console which brings back the effects signal from the echo chamber or other reverberation effects device).

Reverb (Reverberation)
1) A shortening of the term Reverberation (the persistence of a sound after the source stops emitting it).
2) Effect which may be added to sound effects during recording or to a voice during performance. Sustains the sound longer than normal, as if the sound was reverberating around a large building (e.g. cathedral). Persistence of sound after the source has ceased.
3) Adding the acoustics of a concert hall.
4) A most basic and necessary effect. Think of it like this. If you stand in a big empty warehouse and shout, “Hey!”, you will hear a sort of “reverberation” surround you. It’s sort of like an echo, but not exactly. Think of it as audio afterglow.

Reverb Time
The time it takes for the reverberation or echoes of a sound source to decrease 60 dB, after the direct sound from the source stops.

Reverb Time Contour
A graph of reverberation time for signals of different audio frequencies.

Reverberant Field
The area, away from a sound source, where reverberation is louder than the direct sound from the sound source.

The persistence of a sound after the source stops emitting it, caused by many discrete echoes arriving at the ear so closely spaced in time that the ear cannot separate them.

Reverberation Chamber
A device built to simulate room reflections.

Reverberation Envelope
Literally the attack, decay, sustain and release of the reverberation volume; in other words, how fast the reverberation reaches peak level and its rate of decay.

Reverberation Time
The amount of time it takes for reverberation to die down.

Movement of the tape quickly from the take up reel to the supply reel (the direction opposite of play).
RF Abbreviation for the term Radio Frequencies (frequencies higher than 20,000 Hz – usually above 100 kHz).

RF Interference
The induction (generation of current by magnetic lines of force cutting a conductor) of RF signals (usually broadcast by television and radio stations) into audio lines causing noise, buzz and static. Also see the term TV Interference.

Rhythm Section
The musical instruments, especially the first instruments recorded in a tune that play rhythmic parts rather than melody parts.

Rhythm Track (Rhythm Tracks)
The recording of the rhythm instruments in a music production.

Ribbon Mic
Delicate mic not suitable for high sound pressure levels. Consists of a corrugated conductive foil strip suspended between opposing magnetic poles which is excited by pressure differences between the front and rear of the microphone and induces a current.

Ribbon Microphone
A microphone with a thin conductive ribbon as both the diaphragm (device that moves because of the sound pressure wave) and the generating element (the device that generates the electricity).

Riding Faders
Adjusting up the faders for low passages so the signal will be recorded well above the noise and taking the faders back down during loud passages to prevent distortion.

A short melody repeatedly played in a tune (sometimes with variation) often between vocal lines.

Ring Out A Room
A testing, often done at the set-up of a sound system for performances, where pink noise is sent through the speakers and the microphones are turned up until feedback occurs.

An undesirable resonance at the cut off frequency of a filter that has a high rate of cut-off.
Rise Time How fast an audio waveform makes a sudden increase to a higher level.

The reduction of signal level as the frequency of the signal moves away from the cut-off frequency, especially when the cut-off rate is mild.

Abbreviation for Read Only Memory.

Room Equalization
An equalizer inserted in the monitor system that attempts to compensate for frequency response changes caused by the acoustics of the room.

Room Sound
The ambience of a room including the reverberation and background noise.

Room Tone
The background noise in a room without people speaking or music playing.

Root Mean Square
The effective average value of an AC waveform, abbreviated: RMS.

Rotary Control
A level or other control in a device that has a circular movement rather than moving in a straight line.

Rotating Head
A circular head with two (or more) gaps that rotates against the direction of tape motion at a slight angle to the tape travel.

Round Sound
A pleasingly balanced sound (having a pleasing mixture of high frequency to low-frequency content).

1) Abbreviation for root mean square. The effective value of a given waveform is its RMS value. Acoustic power is proportional to the square of the RMS sound pressure.
2) The effective average value of an AC waveform.

RMS detecting
A control circuit that recognizes and responds to the effective average, the RMS level (see preceding entry) rather than to the peak level.

An abbreviation of Reverb Time (the time it takes for the reverberation or echoes of a sound source to decrease 60 dB, after the direct sound from the source stops).

Ability to withstand a lot of use, rough use or abuse.

A low-frequency noise, especially that caused by earth/floor vibration or by uneven surfaces in the drive mechanism of a recorder or playback unit.

To perform a function or command (said of a computer).

Run Down
Musicians playing the tune before recording so that the engineer can get levels and check the sound quality.

Run Off
A quick reference mix recorded on cassette (or other format) after a multitrack recording or overdubbing session, so the client can listen to what was recorded.