On Tue, 26 Jun 2012, Dominique Michel wrote:
Le Mon, 25 Jun 2012 14:08:07 -0400,
Jerry Geis <geisj@xxxxxxxxxxxxxxx> a écrit :
The best things to do would be to use something like a dbx, a
feedback suppressor. The problem is than they are expensive pieces
of hardware. The principle is simple: above a given (adjustable)
input level, you get an output level with a gain of 1, and under
this given input level, you get a gain (adjustable)< 1. That way,
the feedback will never begin, so it will never get the opportunity
to become louder and louder. The dbx are mostly used to suppress
feedback on stages.
It should be very easy to implement such dbx as a software
effect, but I don't know if something like that already exist for
linux.
Ciao,
Dominique
Dominique,
I did some quick searching and didnt see anything like that.
Is this something you can implement?
Unfortunately not. I am good with hardware, but not a programmer.
If using jack, you can try 2 or 3 effects into the jack-rack.
One is the crossover-compressor. The other is the RMS expander. Maybe
you can find some setup with them that would do the trick.
Another way to suppress the feedback would be to re-tune the audio.
Generally, feedbacks are beginning at a given frequency and into a very
small bandwitch. By changing the pitch just a little bit will suppress
the feedback. You can do that with the jack-rack if rubberband is
Well no. It it is really feedback, it indicates an insability of the response
and that instability will manifest itself always, triggered if nothing else by
noise. You need to decrease the amplification of that frequency band. This is
most easily done by decreasing the amplification overall, especially as which
frequency feeds back can depend on exactly where you position your head, or
your hands, or the wall, or whatever. Ie, Unless the physical environment of
the speaker and microphone is exactly fixed, the frequency at which the
feedback occurs will depend on that environment.
(I have no idea what your geomentry is so feedback could even be coming via
the computer case, rather than through the air.) Anyway, decrease the overall
amplitude of either the mic input or the speaker output.
installed. It come with a LADSPA plugin called Rubber Band Pitch
Shifter in the jack-rack.
Thanks,
Jerry
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