My theater is currently running with the center
cluster 6-7 feet behind the front
edge of the
stage area (bowed
stage front), and currently I'm right on the
edge of
feedback, walking on eggshells every show. There are mounting issues that prevent me from moving them forward right now. So some things I did that allowed me to control the
feedback reasonably well:
1) keep the center
cluster on its own volume control. I run my soundboard using the sub outs so I can keep the fronts, rears, and center
cluster all on separate controls. If I sense
feedback coming and/or the actors step forward, I can
pull down the centers 5-10db, enough to squash the problem momentarily.
2) I don't have an EQ set up yet, but when I do I'm sure I will be able to get some more volume out relative to what I can do now. I am also considering a
feedback suppressor. Although they appear to be 'giving in' in the general sound community, a good one like the DBX AFS 224 might provide good notch filtering when needed to deal with these issues. I will try EQ first, then AFS if the EQ doesn't do it.
3) The speakers themselves can make a huge difference. Our first attempt at a center
cluster was a pair of Kustom 100s. They were pathetic ... sound bled everywhere, you pretty much got
feedback when you turned them up at all, no matter where the actors were. Replacing them with the
Mackie SRM450s made a huge, huge difference. The Mackies control the sound projection pretty well -- so you get lots of sound out towards the audience, and little back into the mics. I'm sure there are plenty of other speakers out there that will do well in this area, so
speaker choice may be as critical as placement.
4) The mics and mike settings can make a difference. Turn your wireless transmitter
gain down as much as you can ... I found that with my cheaper lavs when the
gain was turned up to high the volume got "spikey" which made it more prone to
feedback. Of course, Good mics will be better at this than cheap mikes. But they may have to be really good. Our AKG C417s are not cheap mikes, but they don't do nearly as good a job as our Countryman B3s.
5) The actors themselves will make a difference. Actors with loud voices require less
gain on the equipment, and in turn less
feedback. For actors with soft voices, my only suggestion is have them mount the mics closer to the
mouse. I use over-the-ear-with-tape mounting which sets up the mic head like a bluetooth
headset, and the mic head can be placed anywhere from sideburn position to almost at the corner of the mouth. I would worry less about how it looks then how it sounds.
Those are my suggestions based on first year doing sound. Let me know if you find any of this to be helpful.
Thanks. John