You're on the right track. Most DSP feedback filters try to track the loudest sinusoidal frequency and then use a notch filter to reduce it. You could try something with [fiddle~], and make sure that the signals you want to pass remain below a certain threshold. Then everything above that could be checked by [fiddle~] which could drive the filter. But really, if you soundcheck things well and keep mic levels within reason, this kind of thing shouldn't be necessary. I used mics and PD for a few years live and never ran into this problem provided I had a soundcheck.

best, d.

tim wrote:

Hi, I'm planning to use a microphone on stage, with pd. With it comes the risk of unwanted feedback. Has anyone done a feedback canceling patch or seen a proven technique ? I don't know much about how this works in commercial devices (and if they really work for that matter), but I suppose it's done by detecting a frequency that peaks and apply a filter on that...