[LAU] Feedback Cancellation Plugin

[Johannes Kroll]

On Sat, 22 Oct 2016 15:50:22 +0000
Fons Adriaensen <fons at linuxaudio.org> wrote:

> On Sat, Oct 22, 2016 at 04:30:00PM +0200, Johannes Kroll wrote:
>  
>  [...]  
> 
> Because there isn't any that really works.
> 
> The basic reason is that the combined response of speaker, room
> and mic in a typical PA situation is very irregular with hundreds
> if not thousands of very narrow peaks, and the frequency of those
> peaks is very sensitive to small movements of almost everything. 
> 
> Simple tricks like adaptive notch filters will maybe give you a dB
> or so extra, but there it ends. 
> 
> The only thing that can work sometimes is shifting all frequencies
> up or down by a few Hz, smoothing out the peaks. Simple to implement,
> usable for speech but usually not for music because it will appear
> to be out of tune.

That's a good hint, thanks. I could try the AM Pitch Shifter or Bode
Pitch Shifter LADSPA plugins. That could be a good enough solution for
me, if it doesn't change the sound too much.