Specifications

8
Operating Manual - CLX-52 and CLX-51 Compressor/Limiter
Compression For Feedback Control
A common ritual in sound system set-up is equal-
izing the room to remove feedback. This is generally
accomplished by turning up system gain to purposely in-
duce feedback, searching for the center frequency of the
feedback, and then equalizing at that frequency to remove
the feedback. Once this frequency has been cut, system
gain is again increased to induce another feedback point,
and the whole procedure is repeated until the engineer is
satisfied that the significant problem frequencies have
been corrected. The major problem with this approach is
that the feedback can easily get out control, and the engi-
neer ends up dashing back and forth between the mixer
volume controls and the equalizer controls, while every-
one in the room plugs their ears and prays it will end
soon. The Ashly CLX-52 (or CLX-51) can turn this pro-
cedure into a fast, painless job, eliminating loud feed-
back levels and the possibility of speaker or ear damage.
Procedure:
1. Set up the CLX unit’s controls as follows:
a. Output level control to -20dB.
b. Input Gain control to 0dB.
c. Threshold control to -30dB.
d. Ratio control to infinity (∞)
e. Attack time to 5mS.
f. Release time to 1 Sec.
g. Limit switch IN
2. Adjust equalizer controls to a flat setting, and
if the equalizer has an overall volume control, boost it by
10 to 15 dB.
3. Open up several microphone input channels
to a normal operating level, with typical EQ settings, and
turn the console master fader up to a louder than normal
setting. At this point, the system should be well into feed-
back, but the room volume will be constant due to the
action of the limiter. You can listen to the feedback at
any level you like by simply varying the CLX’s output
level control, although below a certain monitoring level,
the feedback will stop.
4. Try to determine the feedback frequency, and
then equalize it by adjusting the center frequency, band-
width, and boost/cut controls of your parametric equal-
izer. (Note: a graphic equalizer can also be used, although
with less accuracy.) After eliminating the problem fre-
quency, try to further define it by sharpening up the band-
width, reattacking the frequency control, and making the
cut shallower, if possible.
CLX-52 in Active Bi-amped System
With Limiting On Lows and Highs
Low High
Mixer
Crossover
CLX-52
Power
Amplifier
CLX-51 Used For Feedback
Control With Parametric
Equalizer in Mono System
Mixer
Power
Amplifier
CLX-51
Parametric
Equalizer
Parallel
Speakers