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Re: De - M/S'ing a file

Subject: Re: De - M/S'ing a file
From: Rob Danielson <>
Date: Mon, 15 Nov 2004 11:54:33 -0600
>The same math works in converting M-S to L-R and back again
>
>The simplified M-S to L-R math is
>M + S = L
>M - S = R
>
>(not including all factors for gain. Y'all know you can tweak the
>stereo separation by adjusting the amount of side in the equation)
>
>By rearrangement and some grade-11 algebra, you can arrive at
>M = L + R
>S = L - R
>(S in this context is synonymous with "difference")
>
>I built a op-amp "double matrix" a few years back which took in L and
>R, produced M and S which was then available via insert jacks for
>alteration, then gets matrixed back to L and R at the output. This
>thing was great for enhancing any stereo signal, not just M-S.
>
>Anyway, to solve your problem,  the first thing I would try is to just
>invert one of the channels to see if the stereo image gets better.
>Failing that, you can try matrixing/dematrixing in different ways.
>
>If you have one, a oscilloscope in X-Y mode is great for resolving
>phase/separation problems.
>
>--- In  "thxdave" <> wrote:
>>
>>  Following on the heels of Bernie's problems, I have something
>>  slightly(?) easier to work on. I made a trip up to the Savannah NWR
>>  (with Walt's help....thanks Walt!) and made a couple recorded
>>  sequences where I swapped my M and S mic leads into my MP2.
>>  Normally, this wouldn't be a problem as I only run a headphone
>>  matrix to hear my stereo spread. However, this time I matrixed the
>>  Tape Out signal as well so my mid and sides got matrixed backwards.
>>  Is there any easy way to undo this backwards signal and return it to
>  > two separate mono tracks?
>

The MDA folks have a free plug named, IMAGE that has presets to undo 
M-S. They also have a stereo synth that uses modulation and comb 
filtering to "Add artificial width to a mono signal" 
http://www.maxim.abel.co.uk/


[Non-text portions of this message have been removed]



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