Re: [tuxdroid-user] Dedicated sound normalizer / multiplexer daemon

[David B. <da...@ja...>]

On Sat, 24 Mar 2007 23:10:08 +0100, Florent THIERY <ft...@gm...>  =

wrote:

>> Otherwise analog ones are possible, starting from the very basic RLC =
 =

>> filter:
>> http://www.everything2.com/index.pl?node_id=3D1391618&lastnode_id=3D0=

>
> Yup, i was thinking of a basic RLC filter... But a software one will
> be easier to do (more unobtrusive at least)
>
> Do you think we can use audacity's nyquist libs?
> http://www.audacity-forum.de/download/edgar/nyquist/nyquist-doc/manual=
/part12.html

As the microphone signal always end up on the computer, software filteri=
ng  =

is the solution to go. A passive RLC filter won't be steep enough to onl=
y  =

cut a narrow band of 500Hz and the AVR won't be able to help as its  =

processing power is way too little for digital signal filtering.

The audacity noise remaoval function works great, you first create a  =

profile from a sample of noise only. Then you use that profile to remove=
  =

the noise an your signal. I don't know if that function is in the nyquis=
t  =

library but that's certainly the one that will give better results.