Compressor/Limiter - dbx PX User Manual

DriveRack PX
Section 5
®
Detailed Parameters
enhanced bottom end with these systems may not be possible and may result in over-
stressing or even damaging your speakers. It is generally not a good idea to use this feature
without a subwoofer. In any case, please refer to your powered mains and powered subwoofer
speakers' frequency response specifications, and avoid forcing them to reproduce low
frequencies that they are not designed to reproduce.

5.4 Compressor/Limiter

The DriveRack® PX also offers legendary dbx OverEasy® Compression with VariKnee , and
TM
proprietary dbx PeakPlus Limiter modules. The Compressor is a full bandwidth Stereo
TM
Compressor located prior to the high-pass and bandpass filters. The Compressor is the perfect
tool for tightening uneven signal sources such as vocals and guitars. The PeakPlus Limiters
are located on each stereo output channel and have been strategically placed for powered
speaker protection. Note that Compressor/Limiter threshold metering can be observed on page
two of the Utility section. The parameters for the Compressor/Limiter are as follows and are
user adjustable.
COMPRESSOR
Compressor On/Off
Turns the Compressor module on and off.
OverEasy (O) Off to 10
There are ten levels of OverEasy® that can be used for the limiters. The point when the
compressor starts to compress is the "knee." When the compressor starts to reduce the level
of a signal abruptly as it passes over the threshold, this is called "hard knee" compression.
OverEasy® (soft knee as it is sometimes called) is when the volume of the sound is
compressed gradually. OverEasy® compression starts to compress before the level of the
signal reaches the threshold and reaches full compression after the level has gone above
the threshold. OverEasy® compression, by its very nature, sounds much smoother and more
natural and will be used for most applications. When it is gentle (natural sounding or light)
compression that you are looking for, the compressor offers VariKnee™. VariKnee™ gives you
ten levels of OverEasy® compression to choose from (1 being almost hard knee and 10 being
the most OverEasy®). This lets you choose the exact knee that is needed for the dynamic
effect you are looking for.
Threshold (T) -40 to +20dBu
Threshold is the signal level at which the unit starts to compress the signal. If the level is
set to -10 dBu, than any signal larger than -10 dBu is compressed while any signal that has
a level that is lower than -10dBu is left at the same signal level. Light compression is where
only the loudest parts of the signal go over the threshold. Very heavy compression can be
achieved by setting the threshold low enough that almost the entire signal content is over
the threshold. For most signals the most natural compression is achieved when most of the
signal content remains just below the threshold and only the peaks cross the threshold.
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