On 05/18/2016 09:04 PM, Emanuele Rusconi wrote:
On 17 May 2016 at 15:45, Jörn Nettingsmeier
<nettings@xxxxxxxxxxxxxxxxxxx <mailto:nettings@xxxxxxxxxxxxxxxxxxx>> 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.
My apologies, you are completely right. I typed this on a train
somewhere without having access to an Ardour system, and I jumped ahead
of myself.
What's missing is one step: create an S' channel just like the S
channel, with right polarity inverted. S -> S' -> Master.
S must have the panner width set to zero, and S' to full width.
The nice thing about an M/S matrix is that it is its own inverse.
That means you can use the exact same operation twice. That's what the
two S busses basically do:
M = L + R (happens because you route both chs of your stereo track to M)
S = L - R (happens because you have one side of S inverted and then sum
in the panner)
L = M + S (happens by feeding M and S' left to Master left)
R = M - S (happens by feeding M and S' right inverted to to Master right)
Of course, you could also use a little plugin to do the matrix operation.
--
Jörn Nettingsmeier
Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487
Meister für Veranstaltungstechnik (Bühne/Studio)
Tonmeister VDT
http://stackingdwarves.net
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