Using the E62i / E31i / E30i to
ORing Out� a Monitor System
One of the most important applications for the E62i/ E31i/ E30iis to removing feedbackENGLISH
from an onstage monitor system. This procedure is sometimes called Oringing out,� since
feedback usually begins with a slight ringing sound at the resonant frequencies where the
loop between microphone and speaker is loudest. Because both the E62iand E31iare
one-third octave equalizers (and thus have relatively narrow frequency bands), they are
particularly well-suited for this application, though you can also use the E30i for this
purpose. The advanced Constant Q circuitry used by all three models ensures that
adjacent program frequencies which may not be causing any problems are unaffected
even when attenuating problem frequencies by their maximum amount.
To ring out a monitor system, start by setting up the stage exactly as it will be used during
performance, preferably with the performers themselves standing in front of the mics they
will be using (this is important since the physical placement of objectsN or peopleN on the
stage can affect the generation of feedback loops in different frequency areas). With
power to all audio components turned off, connect the E62i/ E31i/ E30ito the monitor
mixer, preferably at its main mix inserts (if these are not available, connect the unit in-line,
between the monitor mixer outputs and the monitor amplifier inputs). (See pages 12 - 13 in
this manual for typical configuration diagrams.) Set the E62i/ E31i / E30i Level slider(s) to
the center detented O0 dB� position. Because youOll only be cutting frequencies, press the
Cut Only switch(es) so that they are on (in the down position). Also, because youOll want to
be able to make deep cuts, set the ?12 dB switch(es) so they are also on (in the down
position). Then raise all front panel Equalizer sliders to their upper-most position; because
the Cut Only switch(es) are on, this represents flat response (no cut or boost).
Next, power up all audio equipment (turning on the amplifiers last) and, using one monitor
output only, gradually turn up the volume while a performer is speaking or singing into the
primary mic for that monitor. Continue slowly increasing the volume until a feedback howl
just begins. Using your ears or an RTA (Real Time Analyzer), identify the approximate
frequency at which this feedback occurs. Lower the corresponding Equalizer slider on the
E62i/ E31i/ E30iuntil the feedback disappears. Then continue slowly turning up the
volume until another feedback howl just begins. Again identify the approximate frequency
of this feedback and lower the corresponding Equalizer slider on the E62i/ E31i/ E30i
until the feedback disappears. Repeat this procedure until you reach the point where many
different frequencies begin to feedback at once or when you find that youOve already
attenuated most of the feedback frequencies that are occurring. This is the point at which
the process stopsN youOve gotten as much gain out of the monitor system as you can with-
out adjusting the physical placement of the mic or monitor speaker. Repeat this procedure
for each monitor output (each time using the primary mic for that monitor).
When done successfully, Oringing out� (which should be done before every performance)
can add another 3 to 15 dB more of usable gain to your monitor systemN so itOs well worth
the time and effort!
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