Файл: Sound Tech Terms Dictionary.pdf

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R-DAT:  Rotary-head Digital Audio Tape:  A standard for digital audio tape recording which
employs a rotating head mechanism similar to that of video recorders.  Two channels of 16-bit
digital audio information, plus subcode and track information, can be recorded onto a tape ap-
proximately 3mm wide, traveling at a very low speed of about 50 cpm.  The tape is housed in a
case similar to a video cassette, though much smaller.  R-DAT machines offer three sampling
rates: 32kHz, 44.1kHz, and 48kHz.  Maximum continuous record time for a cassette is two
hours at standard play and four hours at long play, with reduced quality.  See also DAT.

reach:  The clear pick-up of quiet, distant sounds by a microphone due to a high S/N ratio.  See
self-noise.  The higher the SPL of the sound source at the mic, the higher the S/N ratio.  Given
an SPL of 94dB, a S/N spec of 74dB is excellent, 64dB is good.  The higher the S/N ratio, the
cleaner (more noise-free) is the signal, and the greater the reach of the microphone.

reactance:  The complex component of impedance.

read:  The quality of a sound in the context of its placement within a film, theater, or other
audio situation is described as how the sound “reads.”  See popcorn noise.

read mode:  In console automation, the operational mode in which automation data concerning
the fader level or other parameter for each channel is read back from data storage and used to
reproduce those settings in real-time, actually controlling each parameter exactly as it was done
on the recording pass.

ready:  An operational mode of tape recorder electronics.  For any tracks placed in ready
mode, the record circuits are enabled.  When the master record button is pushed and the tape
begins moving, the ready tracks begin recording.  The opposite of safe mode.

RealAudio (.RA):  RealAudio files use a proprietary format designed specifically for playing
audio-on-demand in real-time over the internet, introduced by Progressive Networks in 1995,
consisting of a server application, and encoder, and a player which works within a Web
browser.  Normally, the RealAudio player delivers 16-bit sound, although an 8-bit option is
available.  Data rates range from 14.4kBps (approximately the sound quality of a mono AM
station) to dual ISDN Stereo at 16kHz, nearly CD-quality.  See RTSP.

real-time:  Occurring at the same time as other, usually human, activities.  In real-time se-
quence recording, timing information is encoded along with the note data by analyzing the
timing of the input.  In real-time editing, changes in parameter settings can be heard immedi-
ately, without the need to play a new note or wait for computational processes to be com-
pleted.  (1) The ability of a computer or other device to carry out a process without noticeable
delay, such as real-time editing on a sequencer where changes are made to the music as it
plays.  The opposite of off-line(1).  (2) In a sequencer, the ability to record MIDI messages as
they are played on a keyboard or other controller, i.e., to behave like a tape recorder.  This is
generally the method preferred by musicians.  The opposite of step-time.  (3) Events which
have to occur at particular times to ensure synchronization between devices such as a timeco-
de message, as opposed to those (non-real-time) events which can occur at any time.  (4) See
System-Exclusive.

Real-Time Analysis:  See RTA.

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real-time control:  A non-preprogrammed control signal generated by the player via a control-
ler such as a pitch-bend wheel, mod wheel, aftertouch (pressure) sensor, footpedals, etc.  It is
common to have one of these real-time controllers affecting the depth (amount) of modulation
signal being sent from some other (nonreal-time) source to the modulation destination.  See
continuous controller.

real-time dubbing:  Duplicating a tape at its normal playing speed rather than at a higher
speed, resulting in better quality than high-speed dubbing.

real-time input:  MIDI input generated in real-time, such as during a performance or studio re-
cording session.  See real-time control.

Real-Time MTC Cueing:  MIDI messages similar to Set-Up which contain information such as
cue points, punch-in/-out points, event start and stop points, and event names.  Unlike conven-
tional MTC Set-Up messages which include details of the absolute times in the future at which
events should occur, Real Time MTC Cueing messages are of the Universal System-Exclusive
Real-Time type and so are to be acted on when received.

reassign:   An output bus designed for internal re-routing and combining within a mixing con-
sole.  See insert point.

recapitulation:  In a musical structure, the final return to the theme from the main opening
section, usually modified to occur in the home key.

reception mode:  See MIDI mode.

reclock:  To align bars and beats in a digital editor to music recorded without a tempo refer-

ence.

reconstruction filter:  In a digital audio system, in order to recover the analog signal from the
digital words, a D/A converter is used.  The output of the converter is a stair-step waveform
which contains a great deal of high-frequency artifacts called images.  To reconstruct a smooth
replica of the original signal, the stair-step is passed through a steep lowpass filter, also called
an anti-imaging filter.  It is similar, or even identical, to the anti-aliasing filter at the input of the
A/D converter, but its purpose is very different.  Also called an anti-imaging filter.  See quantiza-
tion, decimation, FIR, IIR.

record-equalization:  Also the same for playback-equalization.  In tape recording, the internal
and complementary alteration of the frequency response of input signals prior to recording and
output signals after playback.  By boosting highs prior to recording and reducing them after
playback, some tape noise is eliminated.  In addition, the equalization curve can compensate
for nonlinear response of the specific type of recording tape in use.  There are a number of
standard record/playback curves.  See also pre-emphasis, RIAA.

record head:  The head on a tape recorder that applies a varying magnetic force to the tape so

that the audio signal will be recorded on the tape for later playback.  A very high-frequency
signal is mixed with the audio program before it reaches the record head.  This bias signal
helps to linearize the over-all frequency response of the tape itself, reducing distortion.

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record-in/record-out:  In SMPTE  timecode synchronization for videotape post-production, the
user-specified SMPTE timecode addresses at which the synchronizer will automatically place
the audio or video recorder in record mode (punch-in) and subsequently cancel the record
mode (punch-out).  See pre-roll, post-roll, mark-in/mark-out.

recordist:  (1) The person who operates the recording device during a recording session, or in
film, the person who is in charge of aligning and loading the recorders and playback dubbers.
(2) The person who records sound during film shooting (Europe).  In the U.S., this person is
called the production mixer.

rectifier:  A device for converting AC to DC.  Rectification is done through a network of diodes

in a power supply to convert power line voltage to DC to power active devices.  Rectification is
also used to recover the signal in an amplitude modulated wave form.

Red Book:  Published by Philips and Sony to set out the complete standard for audio CDs so
that all CD players will be compatible: uncompressed, 16-bit, 44kHz audio data.  The Yellow
Book publishes standards loose enough to allow computer manufacturers to make CD-ROM
players, thus all CD-ROMs are not compatible with all players.

reduction:  (1) The mixing of a number of tracks of a multitrack recording to produce a mono
or stereo master, also called mixdown.  (2) In music, an arrangement of a full score for perform-
ance by a smaller group of instruments or, more typically, just for piano.

redundancy:  The digital transmission of more bits than strictly necessary in order to improve
the reliability of the transmission, such as ECC encoding.  See error correction.

reel motor:  In a tape recorder, the motor that controls the motion of either the feed and/or
take-up reels.

reel size control:  On a tape transport, the control that maintains proper tape tension by ac-
commodating for various sized feed and/or take-up reels which have different amounts of an-
gular momentum.  Newer machines use an infrared or other beam to automatically measure
and set the tensions for the various reel sizes.

reference frequency:  See line-up tone.

reference level:  (1) The reference level on an audio device is a signal level near the maximum
possible for the device but low enough to ensure low distortion.  (2) The reference level of a
power ratio is the unit of power (i.e., watts or volts) being compared.  See decibel.

reference source:  The clock signal used to determine the rate at which a timecode generator and
synchronizer will run; the master clock generator.  The reference source can be thought of as the
system master clock.  The reference source can be an internal crystal sync, video sync, AC power
pulse, external pilot tone, or the timecode reader.

reference tape:  A laboratory-recorded test tape which contains a series of line-up tones all re-

corded at a known, standard level or fluxivity.  The tape is used to verify the performance of
the recorder’s playback system.  Once this is done, the record system is adjusted to produce a
signal that, when played back on the playback system, are identical to the input signal.  Also
called a test tape.

reference tone:  See line-up tone.

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reflections:  Sounds that do not take a direct route to a person’s ears, but which bounce first
off of a stage, balcony, wall, or other non-absorptive boundary before arriving at the ears.  The
combined audio effect of all of the reflections of a sound is called reverberation.  Early reflec-
tions are the first reflections to reach the ears and sometimes sound distinct, like little echoes.
Closer instruments will generally have a longer delay between the initial dry signal and the
first early reflections.  See also ESS.

refraction:  The splitting-up of a complex sound wave into separate frequency bands as the
original wave passes from one elastic medium into another, e.g., from air into water.  Simi-
larly, a prism disperses white light into the familiar rainbow of colors, bending the shortest
wavelengths (violet) the least, and longest (red) most.  See diffraction.

regenerating timecode:  In copying a video or audio tape with SMPTE timecode, the process of
reading the code from the master tape and creating a perfect electronic duplicate of it for re-
cording on the copy.  The new code is created by a separate device and is necessary to ensure
that the audio or video copy is free of timing errors and dropouts.

regeneration:  (1) See feedback and resonance.  (2) See timecode regeneration.

register:  A specific part of the pitch range of an instrument, voice, or melody, e.g., a cello in its
tenor register.  See also tessitura.

Registered Parameter Number (RPN):  An extension to MIDI which allows for additional
Control Change messages.  RPNs have a Control Change number of 100 (LSB) and 101 (MSB).
These are defined in the following way:

Registered Parameter Numbers

MSB (CC 101)

LSB (CC 100)

Parameter

00

00

Pitch-bend Sensitivity

00

01

Fine Tuning

00

02

Coarse Tuning

00

03

Tuning Program Select

00

04

Tuning Bank Select

Unregistered Parameter Numbers (NRPNs) are vendor-defined and may vary among systems.
NRPNs have a Control Change number of 98 (LSB) and 99 (MSB).

registration:  The choice of stops, i.e., timbres, in organ music.

regroup:  The transfer procedure in which material is copied from one medium to another,
e.g., from multiple units of mag film to a multitrack, to facilitate re-recording.  For example, a fa-
cility might have only five playback dubbers on a re-recording stage, and they might transfer
twenty units of mag film to 24-track tape in four passes.  See also transfer.

rehearse mode:  In SMPTE timecode synchronization for videotape post-production, a syn-
chronizer mode that simulates the engineer-specified operations, including record-in and re-
cord-out commands) at the designated code addresses, but does not actually punch-in and -out.

reinforcement:  An increase in acoustic or electric amplitude that occurs when two or more
waves are, to some extent, phase coherent.  The opposite of phase cancellation.

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relay:  An electromechanical device, essentially a solenoid-operated switch.  Largely superseded
by the transistor except in certain high-current applications.  One possible such use is in ampli-
fiers where a relay may break the connection to the loudspeakers before very high amplitude
sounds can damage the loudspeakers.

re-laying:  To post-stripe a video master tape, recording the mixed film soundtrack back onto the
tape after it has been striped for post-dubbing or the addition of narration, music, and/or ef-
fects.  See layback recorder.

relay station:  In broadcasting, a remote site with equipment to receive a signal, either through
a telephone line (sometimes called a music line) or a microwave link, and retransmit it for im-
proved local reception.

release:  (1) The portion of an envelope that comes after the sustain portion and is the amount of
time it takes for the sound to go from the sustain level back to silence.  The release segment
begins after the key is lifted, i.e., the release time to zero-level after a MIDI Note-Off message
arrives or the key is released.  See ADSR.  (2) The time it takes for a compressor’s gain to come
back up to normal once the input signal has fallen back below the threshold.

release loop:  A set of loop points that define a portion of the sound to be played repeatedly
during an envelope’s release phase.  A release loop starts playing back after a key is released
when sample playback will finish the current pass through the sustain loop and then move on
to the remainder of the sound, which may or may not contain a release loop.  The release loop
will be heard for the length of time determined by the release time parameter setting.

release print:  A composite print of a film made for general exhibition purposes.  Release
prints are generally made using the same exposure, color balance, and effects employed in the
final answer print.  See internegative, EK neg.

release time:  The length of time it takes for a signal processing device, generally a compressor,
limiter, or expander, to return to its nominal gain-before-threshold, once the input signal level no
longer meets threshold conditions.  See attack time.

release velocity:  The speed with which a controller key is raised or otherwise released, and the
type of MIDI data used to encode that speed.  Release velocity sensing is rare but found on
some instruments.  It is usually used as a rate control for the release segment of the sound enve-
lope.

reluctance:  The opposition to a magnetic force or field, exhibited by another field and its
source, such as an electromagnet, or by unmagnetized but potentially magnetic objects such as
the oxide domains on magnetic recording tape.

remanence:  Also called remanent flux.  The amount of magnetization left on magnetic recording
tape when an applied magnetic force is removed.  Measured in lines of force per quarter-inch
of tape width.  See flux density, gauss, hysteresis, residual magnetization.