EAW DX1208 Help File page 24

can be used in combination with the DX1208's Automixer to increase the Automixer's
effectiveness. See the
Parameters
•
Threshold
•
Attack
•
Release
•
Depth
•
Bypass Gate Bypasses the Gate without changing the Gate's settings.
Compressor
Description
Each of the twelve DX1208 Input Channels is equipped with a Compressor that occurs
between the Gate and the 6-band EQ in the DX1208 signal
to reduce the dynamic range of signals for effective combination with other processor input
sources, as well as optimize the processor output for the amplifiers, speakers, and SPL range
of the listening environment.
In typical sound reproduction systems, the dynamic range of most input sources, particularly
microphones, is much greater than the system can allowably reproduce. This is primarily
because there are limits to both the minimum and maximum acceptable SPL level of the
system, defined exclusively by the acoustical environment in which the system is installed.
The loudest SPL that does not disturb the listeners defines maximum level, and the minimum
level necessary to produce acceptable intelligibility above the ambient background noise
defines the minimum level. For example, in a popular music concert environment with a large
audience and large PA system, this dynamic range may extend from 80 dB
a working dynamic range of 35 dB. In restaurants, boardrooms or other environments in which
permanently installed commercial sound processors such as the DX1208 are deployed, the
acceptable range may be only 15 to 25 dB, which is far less than a typical dynamic range of a
microphone input, which may range from 30 to 80 dB or more. The amplifier electronics and
speaker transducers can also limit the overall dynamic range of the system, but in commercial
applications these are usually less of a limiting factor than the acoustic environment.
Compressors work by reducing the gain of a signal only when the signal exceeds a defined
threshold level. When the signal falls back below the threshold, the volume is returned to
unity. The amount of gain reduction is determined by a ratio control; the speed at which the
compressor reacts to the signal is defined by the attack and release times. Any overall gain
loss from compression can be compensated for using a gain makeup control. An example of a
compressor input/output transfer curve is shown below.
Automixer section of this helpfile for more information.
When a channel's signal level is below the Threshold setting, the gain is
reduced by a fixed amount equal to the Depth setting. When the signal
level exceeds the Threshold, the gain is set to unity.
Determines the rate at which the Gate increases gain from Depth to
unity once the signal exceeds the Threshold. The rate is determined by
the formula (30 dB/[Attack]) dB/second.
Determines the rate at which the Gate decreases gain from unity to
Depth once the signal falls below the Threshold. The rate is determined
by the formula (30 dB/[Attack]) dB/second.
Specifies the amount of fixed gain reduction that is applied to the signal
when the signal is below the Threshold.
chain. Compressors are designed
to 115 dB
SPL
, for
SPL
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