[CM] noise reduction with snd

[Moritz Lennert]

Ralf,

Yes, my problem is speech recordings. The equipment is certainly the main source of noise, but I think the presence of computers and screens also cause a constant background noise.

Most tools mentioned so far (thanks to everyone for all these ideas !) do not seem to enhance the quality significantly (or I'm not using them correctly...).

I think you're right in saying that I might "just" need to isolate the speech, but that was part of my question. As I am a complete newbie in the field, I don't really know what "apply both a lowpath and a highpath to the original signal" means. I understand the concept, but I don't know what this means in practice. That's why I asked about info in that direction. So, if you have some references or some general tips on how to approach this that would be good.

Moritz


On Fri, Aug 23, 2002 at 10:45:58AM +0200, rm at fabula.de wrote:
> Let me jump out  of my lurking state here ...
> If i understand the original poster's question right he i
> asking about background noise removal from speech recordings. The tools
> mentioned so far are probably nice to remove scratches and dust noise
> from old vinyl recordings but probably not so good for the task under
> discussion.
> Moritz, you forgot to mention where the noise on the tapes(?) comes
> from. Is it environmental noise or is it noise introduced by the
> probably bad recording equipment. If you just need to isolate the
> speech part to get a clearer understanding of the text you might be
> able to use the ol' telephone trick: human speech stays comprehensible
> even if one removes major parts of the spectrum. You could apply both
> a lowpath and a highpath to the original signal, and, unless your noise
> happens to be in the same area of the frequency spectrum as the speech
> component, get a much more understandable speech signal. It's been quite
> a while since a last worked with/looked at human speech, if you need more
> help send my an email and i'll try to dig up some notes/literature.
> 
>  Ralf Mattes
> 
> On Thu, Aug 22, 2002 at 07:02:35PM -0600, kelly george hirai wrote:
> > csound comes with an outboard de-noiser called denoise. i have used it
> > with much success to get rid of hiss. check the comand line parms for best
> > results, the default settings are not very good. kelly
> > 
> > On Fri, 16 Aug 2002, Michael Edwards wrote:
> > 
> > > Hi Moritz,
> > >
> > > Noise removal is a very tricky business, way over my head to be honest,
> > > but I found a nice little app that's idiot-proof (there's only one
> > > slider to fiddle with) and costs only $20.  I'm sure a lot people will
> > > find it too limiting but I've done many a clean-up job with it and swear
> > > by it.  You'll find it below:
> > >
> > > http://www.excla.com/WAVclean/English/
> > >
> > > Good luck,
> > >
> > > 	Michael
> > >
> > >
> > > mlennert at club.worldonline.be schrieb:
> > > >
> > > > Hello,
> > > >
> > > > I am a complete newbie in the field of sound editing, so please tell me if I'm completely out of my league and if this isn't the right place to ask these questions.
> > > >
> > > > I have been conducting interviews for my MSc dissertation and am now in the process of transcribing them. However, my recordings are not always of very good quality and I often have heavy background noise. Since this noise is quite constant and homogenous, I was wondering whether it would be possible to filter it out in order to hear the voices more clearly. I've tried some noise reduction with 'audacity', but the result was not extraordinary. Is it possible to reduce noise in snd ? And if yes, could someone just briefly list the steps I have to follow, or a source of information about this ? I have read through the manual, but since I'm not familiar with the vocabulary of sound engineering this is not always easy.
> > > >
> > > > So any hint would be welcome.
> > > >
> > > > Thanks in advance !
> > > >
> > > > Moritz
> > > >
> > > >   ------------------------------------------------------------------------
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> > >
> > 
> > kelly, angel, riley & cameron hirai
> > 343 Pennell Circle #3 Tallahasse FL 32310  usa
> > http://www.unm.edu/~khirai
> > "... because writing music is easier than running the world." Jim Atkins
> > 
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