Mid side decording.

Please excuse me if this is well known, however I have not found anything in the index or forum as to how to implement M-S input. I am using a Neumann RMS 191 system. I can output MS ( + or-) and XY ( + or-). If I input them as XY I can use them as a stereo pair. I’d like to use them as a MS pair. Does the software allow this? Can this is placed into discussion to be added?
Thanks. drsinus.

Whatever microphone configuration you have, it is still 2 channels that you are recording.
Audacity assumes that a 2 track recording is standard L/R stereo, however, once you have recorded the two channels, you can split the stereo track and process them in any way that you want.

Ok…I understand that I can input those into the program as XY. DO I split the ‘y’ into a stereo pair and form the sound stage by balancing the stage with the ‘Y’ pair and then blend this pair into the ‘X’ to achieve the desired result? :question:

Recording with X/Y stereo, you just put one on one channel, and the other on another. Pan one to the left and the other to the right and that’s all there is to it. The further they are panned, the wider the stereo separation, so if you just leave it as a stereo recording you have maximum stereo separation. If you want to narrow it a bit, then split the stereo track and set each to “mono”, then pan each track the desired amount.

If you want extreme stereo, you can mix in some of the right channel inverted into the left channel and some of the left channel inverted into the right channel (though this will usually be too much).


Recording in M/S and keeping the matrix will give you the most post production flexibility. Here is what I recommend:

Block description
Record using mid/side.
Duplicate side track and invert phase.
Pan mid track to the center and the 2 side tracks full left and right.
Playback and adjust stereo width using gain on the side tracks.

Full instructions for Audacity

  1. Record your session in mid/side using track 1 for mid and track 2 for side.
  2. Using the track drop down box select “split stereo track”
  3. Make a new third track by selecting “tracks”, “add new”, “audio track”
  4. Click on the track description for track 2 to select all its audio
  5. Copy track 2 audio by selecting “edit”, “copy”
  6. Click on the track description for track 3 to select it and click “edit”, paste"
  7. Invert the phase on track 3 by clicking “effect”, “utility”, “invert”
  8. Make tracks 2 and 3 a stereo pair by clicking the track drop down box for track 2 and selecting “make stereo track”
  9. Using the track drop down box for track 1 select mono.
  10. You should be able to adjust the width of the sound stage by adjusting the gain slider for the stereo track.

Depending on the absolute phase and direction the mid capsule was facing when recording you may have to flip left and right on the side channels to keep the sound stage consistent with the original performance.

Watch out for the overall gain that you are adding so that you don’t create clipped samples.

Feel free to message me if you need some help.
Good luck and have fun.