Feedback Elimination

[mbuster]

Here's a question for any live sound guys out there. This may be way off, but If you had a very short delay device, not a typical delay, but one where any input would be delayed say 8ms before hitting the output. I don't mean doubling either, I just mean the original signal must wait 8ms before it gets sent out. Would something like that be able to eliminate feedback on a stage mic? There would be no open circuit between the mic and the speakers at any time. The speakers just get that delayed signal. At work I put in something similar in an overhead paging system in a factory where feedback was a huge problem.

 

[TexRoadkill]

Interesting idea. I can't say that I've ever really tried it. Sound takes roughly one MS for every foot of travel so there is essentially a 5-20ms delay already before most mics pickup the direct sound. I would imagine there is some delay setting that beyond that number feedback is impossible. You would then subtract the distance of mic to monitor from that number and have no feedback.

Of course performing with a delayed monitor would be a whole other issue.

 

[Light]

Doesn't work, I am afraid to say. Good idea, but the delay would have to be much longer to work. Feedback more of an issue of frequency than anything else. Every mic has its own resonate frequencies, based on the overtone series, and it will always try to feed back if too much of those frequencies are present repetitively. The trick is to reduce those frequencies.

And trying to perform to delayed monitors would be imposible, to say the least. As it is usually monitors which feedback...


Light

"Cowards can never be moral."
M.K. Gandhi

 

[masteringhouse]

Here's a question for any live sound guys out there. This may be way off, but If you had a very short delay device, not a typical delay, but one where any input would be delayed say 8ms before hitting the output. I don't mean doubling either, I just mean the original signal must wait 8ms before it gets sent out. Would something like that be able to eliminate feedback on a stage mic? There would be no open circuit between the mic and the speakers at any time. The speakers just get that delayed signal. At work I put in something similar in an overhead paging system in a factory where feedback was a huge problem.

It would delay the feedback by 8ms.

 

[mbuster]

I figured there was some reason it wouldn't work, or else that's what everybody would be doing. Looking back, that must be why the telephone paging device I talked about actually waited until the person was finished to play back. Not an issue with overhead paging, unworkable for performance. Thanks fellas.

 

[DigitalDon]

Cut some around about 4KHz on you EQ. Seems to work pretty good most of the time. Also, Behringer makes a feedback destroyer (forget the model) that supposedly works very well. You could also look at a mic with a tighter (supercardoid) pattern as long as your vocalist knows how to work the mic properly (can stay on axis).

DD