Файл: Sound Tech Terms Dictionary.pdf

B

bit resolution:  See bit depth.

bit shifting:  A technique for lossless compression which, rather than encoding the entire data
word, only bit cells with data (ones) are stored, and the null data (zeroes) are removed.  For
example, if only 19 bits of a 24-bit word contain data, only those bits are transmitted.

bit-splitting:  A feature on some A/D converters, digital recorders, DAW or other digital de-
vices to choose word lengths to accommodate various output channels, such as a choice be-
tween six outputs at 20-bit resolution, or four output channels at 24-bits per sample.

black-burst:  A type of clock reference, this is essentially a video signal without any picture
and without any positional information.  Also known as house sync as a black-burst signal is
typically distributed throughout a recording/editing facility as the facility master clock due to
the extremely accurate clock signal provided.  See video black.

blacking:  The recording of a periodic signal on a blank video tape which marks the start of
each video frame.  See video black, video sync, control track.

black-track print:  A version of the answer print which has no sound, i.e., it is “silent,” made

from the original camera negative.  The first answer prints are usually black-track in order to
proceed with the color timing, even when though post-production sound has not been
finalized.

blanking interval:  The blanking interval occurs at the end of each video frame, during
which video information is absent.  The interval occurs when the CRT electron gun scanner
goes from the bottom-right corner of the screen to the beginning of the next field(4) in the
top-left corner.

bleeding:  See crosstalk, channel separation.

blimp:  A solid cover for a motion picture camera, designed to completely contain camera
noise.  A barney is a padded cover for a portable camera which attenuates, but does not
eliminate, camera noise.

blocking:  Plotting actor, camera and microphone placement, and movement in a produc-
tion.

Blue Book:  A CD specification for data, as opposed to sound or video.

Blumlein pair:  A stereo miking technique which uses two figure-eight mics, crossed at a 90˚
angle, set up as closely as possible to one another.  This is also sometimes called coincident
figure-eights.  See also coincident pair.

BNC:  (1) Bayonet-Nut Coupler.  A two-conductor, low voltage, locking connector most
commonly used for the connection of video and high-frequency clock signals.  (2) Blimped
Newsreel Camera.  The 35mm Mitchell Camera model which was the industry standard for
over 30 years.  See blimp.

board:  A synonym for a recording console or mixer.  (2) Short for a film storyboard.

B

boom:  (1) In general recording, any sort of microphone stand with extending sections that
allows the microphone to tilt and be pointed at a target, such as above a performer or some
section of an orchestra, etc.  Also called a fishing rod, although the latter usually refers to a
lighter-weight rig more suitable for close miking.  (2) The LFE in a mix.  See baby boom.

boomerang:  To mix a sample with a backward version of itself.

boost:  Boost refers to an increase in amplitude, usually of a specific frequency or within a
frequency band.  Equalizers, the most common of which are tone controls, cause boost or cut
of selected frequency ranges.

boost/cut control:  A single control which has “no change” at its center-point.  If the knob is

rotated counter-clockwise, the input is attenuated; rotated clock-wise, the input is amplified.

bootstrap:  An arrangement where the apparent impedance of a circuit element is reduced by
applying an appropriate feedback voltage to it, improving the linearity of a circuit, thus re-
ducing its distortion.  It is especially useful in circuits that are required to carry a very wide
range of power or voltage levels.  Used in power amplifier output stages.

bounce:  In multitrack recording, the process of recording several tracks and mixing those
sounds down to one or two unused tracks.  For example, on an 8-track recorder, you could
record six tracks, bounce them down to the two remaining tracks, freeing up the original six
tracks for recording use.

boundary effect:  A sound reflection effect due to room modes (standing waves) which accu-
mulate at walls.  Sound wave reflections appear to make the localized sound level increase
as all of the room modes terminate at the boundary (wall).  Essentially as the wavefront ap-
proaches the wall, the amounts of molecular motion become smaller and smaller while the
pressure differences become greater and greater as the wall resists the motion of the air
molecules, the wall becoming a pressure node.  The rigidity of the wall surface determines
how much the pressure rises, i.e., how much of the pressure is reflected versus how much is
absorbed.  This occurs on a mode-by-mode basis at each resonant frequency.  At very low fre-
quencies, nothing large is rigid.  However, at higher frequencies, boundary effect is more
pronounced, e.g., frequencies above 100Hz in a room with typical walls.  A related effect is
often observed at a control room window, where the window itself will resonate at one or
more resonant frequencies so that the window passes the resonant frequencies through to
the (recording) space on the other side, somewhat reducing the boundary effect within the
control room, but not providing sound isolation from the adjacent space(s).  This last effect is
worse for lower frequencies as higher frequencies tend to be absorbed by the glass in the
window.  Also called the pressure zone effect.  See absorption coefficient, bass build-up, bass trap.

boundary microphone:  A boundary mic uses a small condenser microphone capsule mounted

very near a sound reflecting plate, or boundary, so there is no delay in the reflected sound.
Direct and reflected sounds add in-phase over the audible range of frequencies, resulting in
a flat response, free of phase cancellations, excellent clarity and reach, and the same tone
quality anywhere around the mic.  Boundary mics have a directional response that is either
half-omni, half-cardioid or half-supercardioid.  An example of a boundary microphone is a
PZM (pressure zone microphone.)

B

bpm:  Beats Per Minute.  The usual measurement of tempo.

bps:  Bits per second.

Bps:  Bytes per second.

break:  In a piece of music, a break is a solo or section of reduced instrumentation, or even

complete silence.  In modern usage the term usually implies an opportunity for an instru-
mental solo.

breakjack:  A type of jack socket fitted with switching terminals, so that insertion of a plug
breaks an existing connection.  Also called a normalled connection.

breakpoint:  On synths and samplers, the specific value at which the tracking of scalable

parameters, such as velocity, starts to take effect, or at which the nature of the scaling changes.

breath controller:  A device which a performer blows into, bites, or presses with the lips,
allowing the articulated sound to be digitally recorded by a synthesizer or sampler.  Breath
controllers can control volume, filter frequency or amount of LFO.  They incorporate a device
known as a stress bridge.

breathing:  Audible fluctuations in the noise level of a signal caused by poorly adjusted or
unsuitable noise reduction systems which produce a variable program level and/or noise floor.
Also called pumping, noise pumping or breathing.  Pumping is caused by the action of a com-
pressor, occurring when one loud sound source causes severe gain reduction in the compres-
sor.  With each loud sound, the level of the other instruments will decrease sharply.  Pump-
ing occurs during program material.  Breathing, on the other hand, occurs when the pro-
gram stops long enough for the compressor to cease its gain reduction, suddenly boosting
the noise floor of the program.  Quantization noise can also exhibit breathing.  See also com-
pander.

brick-wall filter:  A very sharp filter which masks any frequency outside the passband, for
example, the lowpass filter at the input of an A/D, used to prevent frequencies above the Ny-
quist frequency from being encoded by the converter.  See aliasing, reconstruction filter, anti-
aliasing filter, decimation, FIR, IIR.

bridge:  (1) Meter bridge.  A structure mounted at the rear of a mixing desk, or on other
equipment such as a tape recorder, which contains a number of VU or PPM meters.  (2)
Bridge mode.  A method of driving a single load, such as a loudspeaker, from two similar
(ideally identical) amplifiers in order to double the power presented to the load; a stereo
amplifier operating at 200W per channel could provide approximately 400W into a single
load in bridge mode.  Many stereo amplifiers designed for sound reinforcement offer this
option.  See bridged mono.  (3) See bridging.  (4) Originally an eight-bar section of contrasting
material in the middle of a song, but later applied to a linking section of any length.  Also
called a bridge passage or middle-eight.  See also break.

bridged mono:  A method of combining both channels of stereo power amplifiers to create a
doubly powerful single-channel (monaural) amplifier.  See bridge(2).

bridge passage:  A section of music which links two musical ideas.  A bridge is usually used
to connect movements in different keys and/or tempos.  See bridge(4).

B

bridging:  The opposite of impedance-matching.  When the input of an audio device is con-
nected to the output of another device, it is a bridging connection if the second device does
not appreciably load the first device and essentially no power is transferred.  The second de-
vice is sensitive to the output voltage of the first device, and this is maximized when the
loading is minimized.  Most audio connections are bridging, and the load impedance is at
least ten times greater than the source impedance.  A bridging connection is made by con-
necting everything in parallel (all the plus inputs connect to the plus output, all the minus in-
puts connect to the minus output.)  This not only allows for a number of loads to be con-
nected to the same source before overloading it, but this also gets the maximum voltage
swing possible from the source.

brightness:  The amount of high-frequency signal present in a sound, which tends to make
the sound appear closer.  The opposite of darkness.

broadband:  Including a wide range of frequencies, generally the entire audio range.  Usually
used in terms of referring to the broadband performance of an audio device with respect to
some specification such as noise, distortion, etc.

B roll:  See A-roll.

broom: To discard recorded sound during a mix.  “Site brooming” is when a director rejects
a whole group of effects, often the product of several days’ work.

BTSC:  Broadcast Television Systems Committee.  The FCC committee that decided upon
the MTS standards for stereo television sound in the U.S.

BTX:  A brand name of electronic devices that will maintain synchronization between two
tape recorders, tape recorder and a projector or video playback machine, etc.  Used primarily
to interlock one or more multitrack recorders to a video playback, for purposes of recording,
overdubbing, or mixing music in sync with picture.  The device uses SMPTE timecode for
electronic control of all machines.

bucking:  The cancellation of one signal or frequency component of a signal by another sig-
nal with equal amplitude but opposite polarity.  See also phasing, flanging, comb filter.

buffer:  An amplifier with a high input impedance and approximately unity gain.  Used, for
example, in a mixer at the back panel outputs for headphones and control room monitors to
prevent the two loads from overloading the fader output and causing A-rolloff in high-
frequency response.  A sort of internal distribution amplifier.

bug:  A small contact microphone, designed for stringed and wind instruments which work
along similar lines to a piezo pick-up.

bulk dump:  A System-Exclusive description of an actual sound sent over MIDI.

bulk eraser:  A tape demagnetizer that can erase an entire cassette, reel of 

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tape without removing the tape from its carrier.  Essentially a powerful electromagnet.
Some bulk erasers have circuits built in that automatically fade the magnetic field up from
and ultimately back down to zero.  This eliminates pops and other erasure noise normally
left on tape if the eraser is suddenly turned on or off.  Also called a degausser.

B

bulk tuning message:  A System-Exclusive message of the non-real-time type that allows the
exchange of tuning data between MIDI devices as well as other devices such as computers,
allowing microtuning or different temperaments by defining a specific pitch value.  The fre-
quency range is from 8.1758Hz to 13,289.73Hz, in steps of one half-step/  2

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=0.0061 cents, for

each of the 128 notes in the MIDI range.  Two messages are involved:  a bulk tuning dump
request message which is transmitted by a device in order to signify that it is ready to re-
ceive, and a bulk tuning dump message which contains the data for 128 tuning programs,
each containing 128 pitch values.

bumpers:  Small segments of music in a television or film score that usually precede a dis-
solve.  In television, usually used before commercial breaks.

burnt-in timecode:  See BITC.

bus or buss:  In a mixer, a path via which the user can route a signal from one or more inputs

to a specified destination.  Typical destinations include: groups, mix, auxiliary send, foldback,
etc.  For example, “routing inputs 1-8 to the mix bus” means that the eight input signals ap-
pear additively at the mix output.

buzz track:  Alignment film used to set the lateral alignment of the optical film recording
areas for replay.

bvox:  See backing vocals.

B-weighting:  Frequency correction approximately corresponding to human hearing at 70dB
SPL.  See A-weighting, C-weighting, equal loudness curves.

bypass:  A facility on an effects unit which allows the user to switch the incoming signal
directly through to the unit’s output, cancelling the effect so that an A/B comparison may be
made quickly between the wet and dry signal.