Re: [LAU] ladspa - noise removal

2008/5/4, cdr <_@email-addr-hidden-your.name>:
> On Sat May 03, 2008 at 09:24:56PM +0200, Emanuel Rumpf wrote:
> > hi
> >
> > Is there any ladspa plugin that removes (background-/silence-) noise ?
>
>
> if its a FM radio recording, you can mono sum the signal to eliminate it in most cases
you mean sum stereo channels -> mono ?
because the noise of each channel is somehow inverted / phase shiftet?
>
> in other cases, grounding can do the trick
how to do that ?

>
> if its analog hiss, from tape or crappy amps, maybe you want to use a simple gate?

yes, I think, that's what I want in this case.

>
> i mean something that just mutes the signal below an adjustable RMS volume
> at least that way its not removing valuable high freq spectrum from even the good parts..

I just tried "Hard Gate" ladspa.
At high values it hacks the sound, creating even more noise.
At low values it hacks start/end of the sound but
removes what I call silence-noise.

So a "Soft Gate" with same fade-in/out might be suitable.
Couldn't find any in the ladspas on my system.
Is it called differently?

jey..just found out, that rezound has a such a gate in the remaster menu.
I got acceptable results with a threshold of about -64 dBFS with audio
normalized at about -0.82 dBFS

I also gave audacity a try. I like the way the noise removal works
there, though I don't know how it changes/effects the sound...

I would use audacity, if it only was stable with a working jack driver..

annotation: It would be usefull, if the ladspas provided a "build-in"
documentation, two/three sentences, that way giving non-engeniers a
better idea, what they'd be doing. will that come with lv2 ?

Another noise problem:
Sometimes my mic-level shows a meter flickering in the lower range,
that doesn't seem to come from background sounds, thus creating
unacceptable noise...
At the moment it's gone, but it would be pretty usefull, to know where
it's coming
from and how to avoid it. electric / magnetic influences by other cables ?

my setup:
low priced dynamic mic plugged via xlr into external ua-25 edirol usb
card (limiter on, phantom off).
the card uses usb power from the notebook.
neither notebook nor peripherials have any ground connection afaikt.

thanks for your comments, suggestions
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Received on Sun May 4 20:15:03 2008