Glossary Of Terms
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Ducking
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No, nothing to do with Donald. Describes the technique of using the level of one signal to
control the level of another. In broadcast applications, a music bed is often automatically “ducked”
whenever the announcer’s voice is heard; it then returns to its original level when the announcer stops
speaking.
Dynamic range
-
The difference between the loudest sections of a piece of music and the softest ones.
The dynamic range of human hearing (that is, the difference between the very softest passages we can
discern and the very loudest ones we can tolerate) is considered to be approximately 120 dB. Modern
digital recording devices are able to match (or even exceed) that range.
Electro-luminescent panel (EL)
-
A component (commonly used in night lights) which lights up
quickly when electrical signal is applied: the stronger the signal, the brighter the light.
Electro-optical compression (“el-op compression”) -
A circuit design whereby a light source and a
photoelectric cell are used for gain reduction.
Flat frequency response
-
No boost or attenuation in any frequency range.
Gain reduction
-
A synonym for compression or limiting.
Insert
-
A place where a signal path can be broken so that a processing device can be placed in line
with the signal at unity gain (no cut or boost). An insert is most commonly a TRS jack with one
conductor being an output (send) and the other being an input (return). The jack is wired with a
normalled
connection
so that with nothing plugged in, the send and return are connected together.
Knee
-
A term used to describe whether a compressor will reach maximum gain reduction quickly or
slowly. A gradual transition is called "soft knee,” while a more rapid transition is called “hard knee.”
The 2-LA-2 utilizes soft knee compression and limiting, which is generally more desirable for musical
applications.
Limiter
-
A compressor that operates at high compression ratios of 10:1 or higher.
Limiting
-
A more severe form of compression, where a high compression ratio (of 10:1 or higher) is
being used.
Line level
- Refers to the voltages used by audio devices such as mixers, signal processors, tape
recorders, and DAWs. Professional audio systems typically utilize line level signals of +4 dBM (which
translates to 1.23 volts), while consumer and semiprofessional audio equipment typically utilize line
level signals of -10 dBV (which translates to 0.316 volts).
Makeup gain
-
A control that allows the overall output signal to be increased in order to compensate
(“make up”) for the gain reduction applied by the compressor.
Memory effect
- In an electro-optical compressor, refers to the fact that it takes a certain amount of
time for the photo-cell to recover after light is removed, depending on how long light had been shining
on it and how bright the light was. Because of this, you can actually "train" the compressor’s response
characteristics by pre-rolling material for a minute or two, essentially saturating the photo-cell.
Mic level
- Refers to the very low level signal output from microphones, typically around 2 millivolts
(2 thousandths of a volt).
