Ashly Parametric Equalizers SC-63 - Manual (Page 9)

boosted 6 dB (half the maximum boost).
The advantage however, is not that we can duplicate what a graphic does, but
rather extend our frequency response plot to affect from nearly one note, to
forty notes (.05 to 3-3 octaves). See Figure D.
Other controls on the SC-66A (see front panel layout on page 3) include; power
switch, master equalization in/out switches, (NOTE: Switch winks to green
when depressed to "in" position. The switch winks to black in the out
position, sets the gain to unity and defeats all equalization in the channel)
individual equalization in/out switches, (NOTE: Switch winks to amber when
depressed to "in" position and affects only the band below it) gain control to
compensate for insertion gain or loss due to the equalization process ( + 15
dB), "peak" indicator light (one for each channel) monitors all potentTal
overload points in the channel and illuminates when the level at one of these
points reaches 6 dB below clipping.
FIGURE D
FEEDBACK SUPRESSION STEP BY STEP SETUP INSTRUCTIONS
1. Set all gain controls on your parametric to 0, and make sure your master
equalization in/out switch(s) are in the out position.
2. Set all equalization controls on your mixer to flat.
3. Make sure no microphone is pointing directly into a speaker.
4. If you have a limiter, adjust its threshold to hold feedback at a low
level.
5. Estimate the relative volume relationships between your vocal microphones
with individual channel sliders on your mixer, and use the master fader
on your mixer to bring the system into feedback. Make sure all other
channel faders are turned down. Do not let the feedback go uncontrolled
or you might damage your high frequency drivers!!
5. Match the first prom inant feedback note with an instrument or your ears,
and check the note against the frequency number on page 20, and reduce
system gain back to about 6 dB before feedback.
Select the most appropriate control band (LOW, MID, HI).