Файл: Sound Tech Terms Dictionary.pdf

E

ER:  See early reflections.

erase head:  The head on a tape recorder that erases magnetic information on the tape,
located just before the record head in the tape path.  A high-level, high-frequency (150-
300kHz) tone, called an erase frequency which, when fed through the erase head, re-
randomizes the orientation of the tape’s magnetic domains so that the signal to be recorded
will have no hysteresis.  See erase oscillator.

erase frequency:  See erase head.

erase oscillator:  A very high-frequency oscillator built into a tape recorder to supply current
to the erase head.  In most machines, the same oscillator supplies the bias and erase frequency.

error concealment:  A technique to reduce the audible effect of a digital error in a digital
audio system when the error cannot be corrected by the techniques of digital error correc-
tion.  Error concealment usually consists of making a smooth transition from the last good
data block before the error to the first good data block after the error, usually in some form
of interpolation, i.e., crossfading.  Error concealment is the reason that a digital copy from
one source is often not exact an exact clone of the digital master.  When duplicating a digital
master, error correction and error concealment algorithms must be thoroughly understood
and the dubs checked for reproduction quality.  See error protection.

error correction (ECC):  Error Correcting Code.  In digital audio systems, the sampled am-
plitudes of the signal waveform are expressed by digital encoding.  If, in the transmission of
the digital words, some bits are missing or incorrect due to tape dropouts, etc., the result will
be gross distortion of that portion of the signal when it is reconstructed.  Error correction is
made possible through the use of a parity check bit added to each data word, as well as more
complex schemes.  See error concealment, error protection, CRC.

error detection:  In digital playback, the use of error bits and data derived from the audio
samples to check the completeness and accuracy of the audio data before passing it on to the
D/A.  See error protection.

error protection:  All of the circuits and data handling procedures that together accomplish
error detection, error concealment, and/or error correction functions in any digital recording and
playback format.

ESS:  Early Sound Scattering.  A design for control rooms where the characteristic reflections

are so uniformly random that they have no character to impose on the listening space.  An
ESS control room is one which features a highly diffusive front end (including the monitor
walls) which scatters the early sound using Schroeder-type diffusers.  The body of the room is
absorbent, with most of the lows damped by membrane panels.  These rooms can be made
fairly live compared to older control rooms, with a flat frequency response and good stereo
imaging, both of which remain stable right to the rear corners of the room.  As compared
with LEDE and RFZ designs.

event editing:  See step input.

exciter:  A device for artificially enhancing a signal by adding new partials to it.  These de-
vices are said to compensate for loss of high frequencies in analog tape recordings.  Also
called an aural exciter.

E

expander:  (1) A signal processing device which is the inverse of a compressor, providing the
gradual attenuation of signals that fall below a user-defined threshold.  This process, known
as expansion, reduces background noise and at the same time increases the dynamic range of
the input signal.  (2) A synth, with out a keyboard or other master controller, often rack-
mounted.  Also called a tone module.

expansion:  See expander(1).

expansion ratio:  In an expander that is working below its threshold, the ratio given by the
number of dB change in input over the number of dBs change in output.  Typical ratios are
in the range 1:2 or even 1:20.  Expansion ratio is the opposite and complement of compression
ratio.

expression:  One of the defined MIDI Controller Change messages, usually assignable to
some parameter in a synthesizer, such as Volume or Filter Cut Off.

extension: Files used by Mac computer application programs to provide additional func-
tionality to the computer’s operating system.  The equivalent of a DLL  (Dynamic Link Li-
brary) file on a PC.

extinction frequency:  In magnetic tape recording, the high frequency beyond which signifi-
cant cancellation occurs because its wavelength on tape, at the specified tape speed, ap-
proaches the width of the head gap.

F

F1:  See PCM-F1.

fade:  (1) Slow alteration of the level of a signal, usually using a potentiometer.  See fade-in/fade-

out.  (2) Of a piece of music, usually commercial music, the repeated section at the end of the
song which is subjected to a gradual fade-out.  See also outro.  (3) Short for fade-in/fade-out.
Optical effects in which a scene is printed with exposure increasing or decreasing to black-
ness for fade-in and fade-out, respectively.

fader:  (1) A variable attenuator, or volume control.  (2) A variable control used to change the

distribution of power between front and rear speakers.

fade-in/fade-out:  A feature of most audio editing software that allows the user to apply

gradual amplitude increase or decrease over some segment of the sound.  Fade-in starts with
no signal and gradually increases the level.  Fade-out starts with a signal present and gradu-
ally decreases the level, normally to silence.  See crossfade.

far-field:  If a sound source is operating in an enclosed space, the SPL will vary with the dis-

tance that the measuring microphone is from the source.  At certain close ranges, the levels
will obey the inverse square law and at these distances, there will exist approximately a free-
field.  At greater distances, the reduction in measured level with increased distance will be
less than predicted by the inverse square, and finally a region will be reached where the level
is almost constant regardless of the distance, and this is called the reverberant field.  The area
between the free-field and the reverberant field is called the far-field.  Its extent is a charac-
teristic of the directionality of the sound source as well as of the acoustics of the room.

FASA:  Frequency, Amplitude, Spectrum, and Ambience.  An audio production method

which is based on the criteria that can be changed in sonic terms to enhance a recording:

Frequency:  Pitch, transposing parts, chord inversions, layering with other octaves.

Amplitude:  Level, use of dynamic range to cut and boost sections, and relative volumes among parts.

Spectrum:  Textures and the range of frequencies present, layering sounds with others, introducing new
textures from other parts, changing the sounds for a part, like playing a percussion line as a bass part,
the contrast in frequency and textures used.

Ambience:  Space, reverb, and image information such as panning, depth, height, forward or recessed,
for each part playing.

Faulkner array:  A near-coincident microphone configuration which uses a pair of figure-eight

microphones, both facing directly forward, but separated by about 8”.

feed:  In signal routing, an output from one device that is sent into another.

feedback:  There are two types of audio feedback:  acoustic and electronic.  (1) Acoustic feed-

back is where a gain control is set too high in a sound reinforcement system and the ampli-
fied sound enters the microphone and is reamplified until a steady howl or whistle is heard.
This is also called regeneration.  (2) Electronic feedback (or negative feedback) involves the ap-
plication of a small portion of the output voltage of an amplifier to the input so as to cancel
part of the input signal, reducing the gain of the amplifier, but also reducing the distortion
and noise introduced by the amplifier.  See bootstrap.  (3) A specific application of feedback in
FM synthesis, where at least one operator in each algorithm is equipped with a feedback loop.

F

feed reel:  The input reel on a tape recorder, from which audio or video tape is fed to the head

stack and onto the take-up reel.

feet/frames:  Footage numbers for film, either separated by a colon or by a “plus” sign.  For

example, 101:16 and 0101+16 both indicate a point 101 feet and 16 frames into the film.  There
are 16 frames per foot of 35mm film, and 40 frames per foot of 16mm film.  See SMPTE time-
code, LFOP, ABS.

FFT analyzer:  A digital device which performs the transformation from the time domain to

the frequency domain of a sound spectrum over a wide frequency range and dynamic range.
It is used to measure distortion, S/N ratio, flutter and wow, as well as the phase response and
frequency response of audio devices.  See Fourier analysis.

fidelity:  The accuracy with which a music reproduction system will recreate the sound of the

original music.

field:  (1) The subjective environment which a listener perceives while listening to sound,

such as a stereo field.  See stereophonic, ambisonic.  (2) The area around one or more micro-
phones; the acceptance angle of the microphone.  (3) The spatial area of electromagnetic force.
(4) In video, a subgroup of visual data consisting of either the odd- or even-numbered lines of
any frame.  In NTSC, for example, each field is displayed separately for 

1

60

 of a second within

the total frame duration of 

1

30

 second.  For each frame, field number one contains line #1,

#3...#525; field number two contains lines #2, #4...#524.  PAL television broadcasts use an
analogous scheme, but has a different frame rate and number of lines per frame.  See blanking
interval.

field rate:  Frequency at which video fields occur:  59.94Hz in NTSC, 50Hz in PAL.

fifth:  The interval between a note and the one seven half-steps above or below it.  See inter-

val.

figure-eight microphone:  A directional microphone whose pick-up pattern resembles the fig-

ure 8, meaning that it is insensitive to the sides but has full sensitivity at the front and back.
As the polar pattern resembles the shape of a cosine curve, the figure-eight microphone is
sometimes also called a cosine microphone.  Figure-eight mics were traditionally ribbon mics,
but now they can also be condenser mics.  Also called a bi-directional microphone.

file format:  The data in a computer file has a particular order and length.  The specification

which determines the structure of the file is called the file format and is software- and/or
hardware-specific.  Files, such as MIDI files, may contain data, instructions to other software
programs and/or hardware devices, and/or programs.  The file may also contain ECC data,
network information, and other non-user overhead data.  Some file formats are made pub-
licly available to allow the implementation of plug-ins; others are proprietary to the vendor.
The file format usually begins with a file header, followed by data, followed by ECC data,
followed by some kind of stop bit, if the file format is variable-length.  See AIFF, RIFF, .AU,
MPEG, .MOD, .RA, SFI, SMF, .SMP, SND, .WAV, HFS, ISO 9660, .VOC.

fill:  The sound between words in a production track that is used both to replace undesirable

noise on the track and to create handles for use in extending the track at the beginning and the
end.

F

filled:  Filled effects is a version of the effects stem(s) of a soundtrack which includes all effects,

including cut effects and Foley.  See M&E.

fill leader:  The film that is inserted into units of mag film in order to keep synchronization

during silent sections.  Fill leader is usually made up of recycled release prints.  See also leader,
plastic leader.

film:  Now, 35mm film accommodates the 6-track digital sound, but previously almost all

films released in 70mm from 1971-1992 were originally photographed in 35mm and then
blown up to the 70mm format specifically for playback with 6-track sound.  The motion pic-
ture exhibition format from 1955-1971, 70mm, contained 6-track magnetic sound, using cam-
era equipment manufactured by Todd-AO and Panavision.  The camera negative was 65mm
wide, with the additional 5mm outside the sprocket holes used for the magnetic stripes on
release prints.  Almost all modern 70mm prints in the U.S. have no magnetic track, but instead
use DTS in conjunction with a wide timecode track outside of the perforations.

The image, in its widest and standard form has an aspect ratio of 2.2:1, which is narrower than
the 2.4:1 anamorphic 35mm format that is the source of many 70mm prints.  However, when
flat 1.85:1 films are blown up to 70mm, they usually retain their original aspect ratio, with
black borders on the side.  the IMAX/OMNIMAX special venue format also uses 70mm film,
although it runs horizontally through the camera/projector, and each frame is 15 perfs long,
as opposed to the standard five perfs.  Sound is always double-system, utilizing mag film or
custom digital formats.

film chain:  A device consisting of a motion picture projector and video camera, used to copy

films onto videotape or to broadcast them directly.  To adapt the 24 fps U.S. frame rate to the
30 fps NTSC video frame-rate, some chains use a projector with a five-bladed shutter, which
shows each frame of film five times onto the vidicon tube of the video camera.  The resulting
120 fps are regrouped four-at-a-time into 30 video images per second.

film footage:  There are 16 fps per foot of a standard 35mm film image, each lasting four

sprocket holes.  At the standard rate of 24 fps, 35mm film runs at 90 feet per minute, or 18
inches per second.  See frame.