From: John Woodgate
Subject: Re: Is it Possible?
Date: Mon, 13 Jan 2003 13:47:47 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Mon, 13 Jan 2003 16:27:30 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that analog wrote (in
<3E2274E7.F59694F9@ieee.org>) about 'Is it Possible?', on Mon, 13 Jan
>First use a pair of opamps to individually invert the left and right
>vocal portion of *both* channels. While you're at it, trim well all
>excess non vocal fat from both signals by band limiting them
>appropriately to taste (say, 200 to 2kHz). Now fold over and mix an
>equal portion of each processed signal into its unprocessed stereo
>counterpart. Serve up the cooked left and right signals via a second
>set of opamp summers. Left "cooked" should equal left "raw" minus the
>inverted vocals from the right channel, and right "cooked" should equal
>right "raw" minus the inverted vocals from the left channel.
OK, we start with L and R, and make -L and -R with inverting followers.
Then we band-limit (why?). Then we add -L to -R, and, to get any sense
at all, divide by 2, to get -(L + R)/2. Then we add these back to the
originals, to get L -(L + R)/2 = (L - R)/2 and R - (L + R)/2 = (R -
L)/2. Play those through a stereo pair of loudspeakers and the sound
appears at far left or far right, depending on the channel balance.
Played through headphones, the sound appears behind you or
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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