Samson E31I - Manual (Page 19)

17
Using the E62i / E31i to
“Ring Out” a Monitor System
One of the most important applications for the E62i / E31i is to removing feedback from an
onstage monitor system. This procedure is sometimes called “ringing 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 E62i and E31i are
one-third octave equalizers (and thus have relatively narrow frequency bands), they are
particularly well-suited for this application. The advanced Constant Q circuitry used by
both 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 objects—or people—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 to 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 8 - 9 in
this manual for typical configuration diagrams.) Set the E62i / E31i Level slider(s) to the
center detented “0 dB” position. Because you’ll only be cutting frequencies, press the Cut
Only switch(es) so that they are on (in the down position). Also, because you’ll want to be
able to make deep cuts, set the ±12 dB switch(es) so they are also on (in the down posi-
tion). 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 until 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 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 you’ve already attenuated
most of the feedback frequencies that are occurring. This is the point at which the process
stops—you’ve gotten as much gain out of the monitor system as you can without 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, “ringing out” (which should be done before every performance)
can add another 3 to 15 dB more of usable gain to your monitor system—so it’s well worth
the time and effort!
ENGLISH