Friggin' Nightmare!


Active Member
Hello everybody,

My students had an opportunity to perform our spring musical in front of the student body. The show went very well with the exception of a maddening issue.

We're running 22 body microphones for the show. They are 9 single frequency AT's, 5 AT3000's and 8 Telex frequency agile microphones with clear scan technology. We had periods of maddening feedback and no matter what my TD tried, she couldn't get it to stop.

I noticed the following:

1. The feedback happened during large group numbers when there were 15+ characters, and thusly microphones, on stage in close proximity.

2. The feedback happened near our wings (where our monitor speakers are).

Any advice what to do to stop it for our opening? I cannot turn down the monitor mix as our piano player is "deaf" and "must be able to hear herself and the singers"... seriously... she'll walk off the set if we turn her monitor system down. Maybe aim that particular monitor mix (we have 2) away from the stage towards only her?


Wow, I hate it when that happens. My first suggestion is to not send a monitor send off of the mic's near the monitor. FOH signal should be OK on those mics. When you get feedback you usually peak the board and can determine which mic is feeding back first (watch the peak light on your sound board). The board op should be able to turn the monitor feed back on after those mics leave the monitor area.
I doubt thaqt eqing out those mics would help much, but might get you a little head room.

Hope this helps.


Well-Known Member
I never use onstage monitors for lavaliers. If the piano player (and the rest of the pit) needs a monitor, point a monitor their way.


Senior Team Emeritus
Premium Member EQ on the monitor mix could help..but there is much more to this than just an EQ problem IMO...

First off--The monitor for the piano player should be next to her by the piano...not in an offstage sidefill. Closer to her means less overall stage volume and thus more focused sound to HER only and not to the whole stage where the mic's are open and can pick up the stage sound. So first--move that monitor to her so its within 3 feet of her position and pointing only AT her. If she is that deaf--get her some in-ears..or get a new piano player. :) If the folks on stage need to hear the piano--that is another mix separate from the piano mix and should be piano only. A cheap in-ears set will cost a couple hundred bucks..but its easier to move the monitor to her. IMO--Never run lav mic's into a sidefill wedge--most lavs unless you get specific styles are Omni directional...they pick up everything equally from all angles. They should be for FOH reinforcement only. If you do need them for some actors to have onstage monitoring--then get yourself Cardioids or hyper lavs and position them the same on every actor for optimum pick up. They will help your feedback issue immensely for on-stage monitoring and allow you to put on-stage monitors for the actors to hear themselves if they need it.

Also to be considered--the gains on the mic's may be needed to be checked and adjusted for sensitivity and have a mix mash of various models and brands--they all need to be balanced and adjusted to each other (ideally--they all need to be the same model of mic for control purposes--the mic, not the transmitter--example: they are all Countryman B3's mics, just have different connectors to use on various transmitter packs for Telex or AT etc As it sounds--you are using vqarious models from various manufacturers--each with their own sensitivity and frequency response which can create chaos for non-experienced folks at the mixing console.). You may have a few that are way too sensitive to pick up softer singers--which is a case for them to learn to project and for which the gain should be adjusted on the console for the FOH mix--not neccesarily on the mic pack. Also--check to make sure your monitor mix is PREfade--so any adjustments in the house are not happening as well on stage...or you will never ever get a clean constant mix level on stage.

Also--If the feedback is occuring en-masse on group stage numbers only, then its either proximity effect as the packs may be too "wide open" for sensitivity (and which you are fighting a losing battle)..which then you need to adjust the sensitivity or collective voume level, But it does not seem from your description like the latter....

Finally--do you know what the feedback frequency IS that you constantly get problems with? i.e. is it a low rumbling that builds, or is it high freqency--cause knowing the range or freq area can give you clues to the problem as well. Low rumblings are usually gain and room and can easily be controlled by adding a HPF to the mic channels as you are picking up general room noise.. So set it to around 315hz or 400hz max, 250 hz minimum. While higher pitched feedback can be gain, EQ or proximity issues...

Not being able to see or hear your exact situation, those are just a few thoughts to look into...



Well-Known Member
Like wolf said, set up a seperate mix for the piano player, maybe putting her mon wedge next to the piano bench, and for the stage wedges just put piano through.

You may want to reset the gains for the mics on the board. Hit the PFL button, and adjust the gain until the bars are around 0 on the meter, always has worked for me.

Also, if there are that many people on stage, try muting some of the mics from the board. Most lavs are sensitive enough to pick up those without a mic (or one with a muted one). I had to do this alot during our annual musical.

Hope you solve your problem.


Active Member
Hi all!

Our opening night was the best we have had. For our community... where Friday night football is the only entertainment that they will even consider to attend at a school... we had a sold out crowd.

Thanks for the advice. I did the following which eliminated 85% of the problems.

1. I had the piano mix (monitor 2) on a stand behind the pit so that they would hear it as well as the actors. I changed it so that it was only aiming at the pit and away from the stage.

2. I noticed (I have 2 monitor mixes) that my TD had mics mixed through monitor 1 by mistake. I eliminated that and we didn't have issues.

3. On the mass group numbers I only un-muted our leads and left the mic-ed major/minor characters muted leaving only 3 - 6 mics on stage.

It worked! :)

You guys are geniuses! I wish I had the tech knowledge that you did (maybe after my masters is wrapped up I will go back for a theater tech degree).

I am forever greatful for your advice!



Active Member
i was having the same thing happen to me during our last few shows. Make sure none of the antennas are crossing too much, or wires going over them or anything. Also, i found that alot of feedback actually came from having people miced on baody lavs and being picked up by house mics as well.. I had all my lavs up on center/mono, and rear with my house only on rear, l/r. Seemed to work pretty good...and if you have a digital board, i was muting house mics and bring lavs back up on everything depending on snapshot andwh and what were on stage.

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