[LAU] denoising audio files

Hartmut Noack zettberlin at linuxuse.de
Wed May 23 21:44:21 UTC 2012

Am 21.05.2012 23:48, schrieb Fons Adriaensen:
> On Mon, May 21, 2012 at 10:04:13AM -0400, Ricardus Vincente wrote:
>> The lack of quality noise-reduction software for linux has been on
>> my mind quite a bit lately. I thought it might be a cool idea to
>> create a Kickstarter project to fund the development for this.
>> Mike from linuxDSP or Fons would be the best choices (I think) to
>> write the plugs.
> :-) Very flattering, but don't expect a single-click solution for
> something as volatile as removing unwanted noises from a recording.
> In some cases (and more often than one would think) it's just a
> matter of some EQ, in other cases a simple noise gate can do the
> trick, and sometimes you'll need a multiband expander using pre-
> measured statistics. It also depends on how the result is going to be
> used afterwards.

In the end it will be either a drum-track or vocal track or anything
else that could have been recorded in a studio in the basement of a
railway-station or it will be a restauration-effort to digitize a
vinyl or cassette.

In all cases: if it is hiss or hum, EQ or gate can help if used wisely
but I do not know any software for Linux that allows to cancle out a
train running through the one great vocals-take -- whithout destroying
the voice in the process that is.

IMHO: to do something like this the best way is to start with a tool
that visualises the sound to allow to really find and technically 
analyse the problem. A human can hear, waht a train is and what a voice 
is, for any software there is only frequency an amplitude so there needs 
to be a tool that allows the human to teach the robot, what is noise and 
what is signal.

The noise-remover in Audacity does that but is far too primitve to 
achieve really good results.

To have the abilities known from Melodyne in Sonic Visualiser such as: 
this part of the wave, this range of frequencies with this particular 
sequence of amplitudes I can see in this graph is the evil one, go! 
Cancle it!

This would be indeed, quite nice, methinks....

best regards


p.s.: I have seen a MAGIX-Technician doing such a trick in Sequoia some 
5 years ago...

> As in many cases, it's going to be the skills of the user rather than
> the tools that are going to determine success or failure.
> Ciao,

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