Subject: Re: [linux-audio-user] Re: Removing distortion
From: Patrick Shirkey (pshirkey_AT_boosthardware.com)
Date: Wed Jul 10 2002 - 18:28:59 EEST
Paul Winkler wrote:
> Patrick,
>
> could you try to find out more about what your friend is doing?
> Because a simple invert ... lowpass ... invert procedure
> will sound EXACTLY the same as doing a lowpass filter by itself,
> unless there is something nonlinear about the lowpass filter being
> used.
>
I have been querying him tonight and have managed to fine tune his
method some more. I think inverting the sound is probably the wrong
description :(
He uses CEP. Essentially what he does is to equilise the wave with a
parametric equiliser so that you have the treble signals almost
seperated from the rest of the wave then he would literally cut the
trebel peaks out of the waveform. you can do that in CEP because they
have some kind of graph interface that has the ability to cut out
everything about the line or under it. Doesn't snd have something like that?
Anyway, then he reequilises the signal to the original settings and
adjust the levels from there. A lot of the finer detail comes from
experience and having good speakers.
He says that there is a set of levels that have been incorporated into
CEP2000 which do the job of seperating the high end from the low very well.
This is all second hand info so please don't shoot the messenger if this
method will not work to standard.
From my experience with denoising it is usually the high end that
corrupts the signal most. A lot of the time the low end stuff gets
buried under the bass and drums anyway.
-- Patrick Shirkey - Boost Hardware Ltd. For the discerning hardware connoisseur http://www.boosthardware.com http://www.boosthardware.com/LAU/guide/ ========================================
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