[music-dsp] Extract the center information from a stereo signal

[Christofer Bustad]

Hi! I've thought a lot about how to enhance/widen the stereo image of a
stereo signal. (I plan to use this in my plug-in Energize which can be found
at www.bustad.com.) I thought that if I could separate the center
information from a stereo signal I could work with just the stereo
information without affecting the center information. Is there an easy way
of doing this? Do I have to do an FFT and look at all the frequencies? I
thought that if I would look at the difference x(n)-x(n-1), I could assign
the common change to the center information, but I haven't tried that yet.
Is there any math that can be applied to stereo enhancement that doesn't
involve the frequency domain (except for L-R and similar things)?

It would be very interesting to hear if anyone have any thoughts about this!

Thanks!
Christofer Bustad