[linux-audio-user] Filtering out sounds?

Arnold Krille arnold.krille at gmail.com
Fri Mar 9 14:58:05 EST 2007


2007/3/9, Eric Dantan Rzewnicki <eric at zhevny.com>:
> On Fri, Mar 09, 2007 at 02:25:03PM -0500, Lee Revell wrote:
> > On 3/9/07, terrence at terrencevak.net <terrence at terrencevak.net> wrote:
> > >        This might sound like a *really* odd question, but here goes.  I'm
> > >also looking for a strictly command-line program.  I have some old tapes
> > >that I'm converting to MP3s so I can get rid of the old cassettes.  One of
> > >these is a tape on which I can't stand the sound of my own voice.  If such
> > >a program exists, I'd love to be able to feed my voice into the program
> > >and then have it filtered out, or at least obscured from, the recording.
> > >Am I shooting at the moon or can this be done?
> > I'm sure it's possible to get close - I think this is what karaoke
> > machines do.  No idea how though.
> I thought they relied on the vocal being panned center and did some
> trick with phase inverting to cancel it out ... but, somehow that sounds
> too simple.

What they do is add the inverted right channel onto the left and vice-versa...

Sounds simple, is simple, removes the bass and doesn't work on all titles.

A friend of mine programmed a version combined with high- and lowpass
to let the bass-part go through the effect and only karaoke-filter on
the higher frequencies. He also made the levels of the inverted
signals adjustable. That way you can select the panorama position to
remove. As a result you could filter either Eric Clapton or BB King on
"Riding with the king" and it sounded rather good.

But beware if you put these signals on a PA (for public karaoke): The
new left and right channels need to be panned. The more the better.
You will here nothing if both channels are panned center. (Because
both channels contain the other one inverted and the result will be
two normal and two inverted channels canceling each other = zero audio
levels...)

Have a nice weekend,

Arnold
-- 
visit http://www.arnoldarts.de/
---
Wenn man mit Raubkopien Bands wie Brosis oder Britney Spears wirklich
verhindern könnte, würde ich mir noch heute einen Stapel Brenner und
einen Sack Rohlinge kaufen.


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