[LAU] Filtering out everything but the centre position in stereo

[David]

On Fri, 23 Aug 2019 at 01:44, Jeanette C. <julien at mail.upb.de> wrote:
>
> is there an effect or a method to filter out everything from a stereo file but
> the "centre"? A sort of reverse karaoke effect.

Hi, my reply is interleaved with others below.

On Fri, 23 Aug 2019 at 04:57, Jeanette C. <julien at mail.upb.de> wrote:
> Aug 22 2019, Ralf Mardorf has written:

> > On the quick my guess is
> >
> > Original left  channel + inverted right channel = plain_left
> > Original right channel + inverted left  channel = plain_right

L + (-R) = L-R = X = what was called above "plain_left"
R + (-L) = R-L = Y = what was called above "plain_right"

> > Original left  channel + inverted plain_left    = middle only
> > Original right channel + inverted plain_right   = middle only

L + (-X) = L - X = L - (L - R) = L - L + R = R
R + (-Y) = R - Y = R - (R - L) = R - R + L = L

So you finish with the same signals that you started with,
except that the channels are swapped.

> That sounds good. Unforunately it didn't work.

Both aspects explained above :)