On 17 May 2016 at 15:45, Jörn Nettingsmeier <nettings@stackingdwarves.net> wrote:

1. you have a stereo track already. disconnect it from the master.
2. create a mono "M" bus-
3. create a stereo "S" bus (yes, see below).
4. route both outs of the stereo track to "M".
5. route the L out of the stereo track to the first input of "S".
6. route the R out of the stereo track to the second input of "S".
7. invert the polarity of the second input of "S".
8. now add your desired processing (usually EQ) to M and S (use mono plugins for S despite the bus being stereo).
9. set the M panner to center.
10. set the S panner to center and maximum width.
11. set the M and S faders to -6dB to begin with, adjust S level to taste.

That's not how you convert LR/MS: in the master bus you'll get a strong left channel and a cancelled right channel.

What you should do is:

1. (L + R) -6dB -> M mono bus, (L - R) -6dB -> S mono bus

2. process as you wish

3. (M + S) -> L out channel, (M - S) -> R out channel

Of course with "-" I mean invert polarity and then sum in the same input. You'll need to use extra buses to perform that polarity inversions. The details of the implementation are a matter of taste: you can use separated mono buses, or stereo buses with the width at 0 (so acting as dual in / mono out).

The point "3" can be used to convert a MS recording to a LR stereo.

-- Emanuele Rusconi