Файл: Sound Tech Terms Dictionary.pdf

F

FM synthesis:  A sound synthesis technique which multiplies sine waves together in an attempt

to generate complex waveforms more quickly (than additive synthesis), usually adding several
of these products together in an attempt to get its more effective results, which is why a 6-
operator FM sounds better than a 4-operator FM as more products are being summed.  See
sound synthesis.

foldback:  The general term for the part of a sound reinforcement system in an auditorium

which supplies amplified sound to the performers so they can hear themselves.  See monitor
mix.

foldback send:  See monitor send.

foldover:  See aliasing.

Foley:  Creating sound effects by watching the picture and mimicking the action, often with

props.  Foley artists, also known as Foley walkers, make use of a variety of objects and/or sur-
faces to elicit realistic sound effects; most commonly used in the recording of on-screen foot-
steps, hence the term “walkers.”  Foley effects are named after Hack Foley, who was the head
of the sound effects department at Universal Studios.  The audio track which contains Foley
sounds is known either as a cloth track (west coast) or rustle (east coast.)

footage counts:  See counts.

formant:  A frequency band in the spectrum of a voice or musical instrument that contains

more energy or amplitude than the adjacent area, i.e., the partials are quite closely spaced in
the region, giving the sound its timbre.  For example, the formants produced by the human
vocal tract are what give vowels their characteristic sound.  See fixed formant.

format:  (1) In vinyl records, the size of the disc and its rpm rating.  (2) The physical specifica-

tions of a specific film or print, e.g., 35mm, as will as the type of soundtrack (optical or mag-
netic, stereo or mono, with or without NR), whether it is color or b/w.  (3) The width of a
videotape, and the designation of the electronic system by which it is recorded.  (4) In radio
and TV, the type of programming featured.  (5) Magnetic tape format.  For any tape recorder
or recorded tape, the number of tracks, their width and position with respect to the tape, and
the overall width of the tape itself.  Tape speed is not always included, e.g., 8-track 1” and 24-
track.  This is usually called track format.  (6) See file format.

forward masking:  See temporal masking.

Fourier analysis:  A technique, usually performed using a DSP algorithm, that allows com-

plex, dynamically changing audio waveforms to be described mathematically as sums of sine
waves at various frequencies, amplitudes, and phases.  The Fourier transform allows a func-
tion that represents an audio signal (signals are in the time domain because they exist in time)
to be transformed to another function which represents the same signal in the frequency do-
main.  The signal in the frequency domain is called a spectrum, and the same signal in the
time domain is called a waveform.

F

four-stage envelope:  The Yamaha DX7 synthesizer introduced a new type of envelope gen-

erator, one which had four rate control and four level control parameters, for a total of eight pa-
rameters.  Each rate parameter controls how long it takes the envelope to move from one level
to the next.  This is referred to as a four-stage envelope because each rate/level pair is con-
sidered a stage.  Technically, an ADSR envelope only has one true stage, the decay/sustain
stage and two more partially controllable stages because the attack and release levels are
fixed at 100% and zero, respectively.

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

val.

four-track:  See quarter track.

fox holes:  Small perforations on 35mm release prints that allowed for the addition of mag

stripe for the CinemaScope process.  This process has now largely been replaced by Dolby Ste-
reo.

fractal music:  Music created by the use of fractal equations.  By assigning musical parame-

ters such as pitch and volume to the x and y axes, it is possible to produce music as the Man-
delbrot set is calculated.

frame:  (1) The internal structural support of a loudspeaker when holds the voice coil and the

diaphragm.  (2) The basic unit of SMPTE timecode, corresponding to one frame of a film or
video image.  Depending on the format used, SMPTE time can be defined with 24, 25 30 or
29.97 frames per second (fps).  (3) In digital audio, a frame is a unit of digital information.  In
the CD, a frame covers six sampling periods, or 136µs.

 Usage and Country

Frame Rate per Second

 Time per Frame

UK and European Film industry

24

41.66ms

UK and European video and TV

25

40.00ms

USA B/W TV and video

30

33.33ms

USA Color TV and video

30 drop-frame (~29.97fps)

33.37ms

frame lock:  Frame lock maintains synchronization between master and slave transports, us-

ing the positional information available in the timecode address.  Also called frame sync.  See
SMPTE timecode.

frame rate:  See frame.

free encoding:  An extension of spaced microphone recording techniques, systems which create

pseudo-stereo from a mono source will also generate a strong surround signal, and stereo-
width controls can be used to manage the balance between frontal and surround channels.
Increasing stereo width also increases the level of the surround channel, whereas decreasing
width reduces the surround content.  This is because a surround decoder will automatically
send anything which is of a similar level, but opposite polarity between left and right chan-
nels, straight to the surround output.  Artificial reverberation, for example, is automatically
spread across L, S, and R.  See LCRS.

F

free-field:  A sound source radiating into three-dimensional space where there are no re-

flecting surfaces is said to be radiating under free-field conditions.  The SPL as measured at
various distances from the source would obey the inverse square law precisely.  There is no
such thing as a true free-field, but it is approximated in an anechoic chamber.  Because all
rooms have at least a small amount of reverberation, the sound field from a source is always
contaminated with reflected sound.  See also far-field, near-field, reverberant field.

FreeMIDI:  A Macintosh operating system extension developed by MOTU that enables dif-

ferent programs to share MIDI data.  For example, a sequencer could communicate with a li-
brarian program to display synthesizer patch names, rather than just numbers, in the se-
quencer’s editing windows.

freewheeling:  A condition in which a clock synchronizer continues to generate timecode even

when it encounters dropouts in the timecode source, or in which a digital audio playback de-
vice continues to generate audio in the absence of, or while ignoring, a timecode input.  See
jam sync.

frequency:  The number of waves (or cycles) arriving at or passing a point in one second, ex-

pressed in Hertz.  See pitch, Appendix D.

frequency distortion:  Frequency distortion results when the amplitude of the output of a

system or a device varies as the frequency of the input varies, while the amplitude of the in-
put is held constant.

frequency doubling:  See doubling.

frequency masking:  An audio artifact which occurs when several sounds are mixed, all

which occur in the same frequency range.  This happens because human ears tend to blend
simultaneous sounds into a single, composite sound.  When several instruments or other
sounds emphasize similar frequencies, those frequencies accumulate and can either become
too dominant or can cause one sound to mask another.  Also called band masking or auditory
masking.

frequency modulation (FM):  (1) A change in the frequency (pitch) of a signal.  At low

modulation rates, FM is perceived as vibrato or some type of trill.  When the modulation wave
is in the audio range, FM is perceived as a change in timbre.  FM synthesizers, commonly
found on soundcards, create sounds using audio-range frequency modulation.  See FM syn-
thesis.  (2) Frequency modulation is the instantaneous changing of the frequency of a carrier
in response to a modulation signal, usually an audio waveform.  As the signal voltage varies
up and down as it follows the waveform, the frequency of the carrier varies up and down
from its nominal unmodulated value.  The FM receiver is tuned to the carrier frequency, and
the received signal, after suitable conditioning, is applied to a special circuit called an FM de-
tector, also called a demodulator or discriminator, which recovers the audio signal.  See ampli-
tude modulation.

frequency modulation distortion:  Examples of frequency modulation distortion are flutter

and wow, and Doppler distortion caused by the motion of rotary (Leslie) loudspeaker cones.

frequency ratio:  The ratio of the higher pitch in an interval to the lower pitch.  See consonant,

harmonic.

F

frequency response:  The amplitude response of a system or device as a function of the input

frequency characteristic.  It is a complex function which describes the way in which the gain
and phase of a system or device vary with the frequency of the stimulus.  Frequency response
is a characteristic of a system or device, not a characteristic of a signal.  See linear.

frequency response curve:  A graph of the frequency response of a device, i.e., the graph of its

output amplitude response vs. the input frequency.  See linear.  For example, the frequency
response curve for a microphone is a graph of the mic’s output level in dB at various fre-
quencies.  The output level at 1kHz is placed on the 0dB line and the levels at other frequen-
cies are placed above or below that reference level.  The shape of the response curve suggests
how the mic sounds; a wide, flat response tends to sound accurate and natural.  A rising high
end or a presence peak around 5-10kHz sounds more crisp and articulate.  Note that the re-
sponse curve is measured at a specified distance from the mic, usually 2-3 feet; the curve re-
flects the performance of the microphone only for that particular distance.

frequency response errors:  Any deviation from a linear output response in an audio device.

frequency shifter:  A device that linearly shifts all the frequencies of a complex input signal.

Also called a spectrum shifter.  All frequency components are shifted linearly, i.e., by the same
number of Hertz, in contrast to a pitch-shift.  In a pitch-shift, all the frequency components are
shifted by a constant percentage, and therefore, high frequencies are shifted proportionally
more than lower ones.  A pitch-shift-by-speed change thus preserves all the musical intervals
between components.  A true frequency shifter, in contrast, destroys the harmonic relation-
ships between the components.  The sound of a consonant musical tone becomes disconso-
nant or clangorous or harsh, depending on the amount of shift.  Frequency shifters are used in
electronic music synthesizers for special effects.

fringing:  A rise in the level of low frequencies when a recording is replayed by a tape head

with a narrower track width than the one used to record the tape.  Low frequencies from the
recorded areas adjacent to those actually being played back bleed into the playback signal.

FSK:  Frequency Shift Keying.  FSK is a sequence of two alternating audio tones, typically

generated by a sequencer, drum machine, or computer MIDI interface, that is recorded on
one track of an audio or video tape for synchronization to MIDI sequencers and drum ma-
chines.  See pilot tone.

full-coat:  Magnetic film coated with oxide across its entire width, available in 16mm and

35mm widths.  Contrast with full stripe.  See mag film.

full code:  A term meaning that a sample word is set to all ones, i.e., that it is representing the

largest number possible at that word length.  This is important in the representation of digital
audio amplitude, where a full code word is equivalent to -0dB headroom, or the amplitude
that is the loudest sound which can be encoded without clipping.  See also digital black.

full score:  A notated form of a piece of music which contains the complete music for all in-

struments or vocal parts, aligned vertically, i.e., the full complement of band parts.

full-stripe:  Magnetic film with oxide coating in just the area where the recording takes place,

allowing the transparent material to be written on.  Contrast with full coat.

F

fullth:  A subjective term applied to a recorded musical program with many voices in the

lower mid-range of frequencies, e.g., cellos and violas, background vocals, rhythm piano, etc.,
giving the mix a lush or heavy richness.  Also called gush.

full-track:  A 

1

4

” tape format in which a single, mono track is recorded across the entire tape

width.  Loosely used to refer to wider tape formats in which each of two or four tracks is 

1

4

”

wide.

fundamental:  The perceived pitch of a sound; the lowest frequency vibration component in a

complex sound which also carries a set of higher-pitched vibration called overtones.  The fun-
damental is always the first harmonic and/or partial component of a sound.  See DCO.

fusion:  In stereophonic music reproduction, fusion is the perception that sounds from two or

more loudspeakers are being produced by a single sonic image.

fuzz box:  An effects device designed to produce clipping distortion, most frequently used

with electric guitars.  See DI.

fx:  See effects.