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M/S recording

Discussion in 'Studio Techniques' started by HKC, Mar 29, 2012.

  1. HKC

    HKC Senior member

    For some strange reason I have never gone into M/S recording. I understand the setup with one mic (often cardoid) pointing at the source and another (figure of 8) pointing sideways and they are placed in front of the source as a T.
    I also understand the division of the figure of 8 into two signals (one +, one -) but I don't understand how to use the Direction Mixer in Logic for the decoding of the signals.
    Could someone please enlighten me how to set it up exactly:)

    PS I assume that recording the two signals, copying the figure of 8 to another track, phase shifting one of them with the gain plugin and then bringing these two up around the mid (the cardoid) would give the same result, or have I misunderstood something.....
     
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  3. Pete Thomas

    Pete Thomas Administrator Staff Member

    With dirmixer, you input mid on left and side on right just choose MS as oppsed to LR, all the decoding is done behind the scenes. Adjust stereo width and/or input gains and constantly check for nice image vs mono compatibility (by monoing the output)

    The mid does not have to be cardioid, it can be omni or even another figure of 8 but pointing forward/backward. (Ideal if you have a pair of ribbons)

    To replicate without the MS matrix in dir mixer you need three tracks:

    The mid and two copies of the side. You then make one of the side tracks out of phase. Then mix the mid in with those two. Constantly check mono compatibilty.
     
  4. Peter Ostry

    Peter Ostry Administrator Staff Member

    The Direction Mixer expects the mid signal to the left and the side signal to the right. Following this rule, pan your recorded mid and side tracks hard left/right, send them to a stereo channel and the Direction Mixer will decode them for you.
    [​IMG]
    Correct.

    [​IMG]

    Not necessarily, the volume relation should be correct, as you recorded it. But you can change the stereo width by changing the relation between the mid and the two side signals.
     
  5. HKC

    HKC Senior member

    Thanks a lot, I will give it a shot during the next week. I record a lot of drums-sessions and often include one mono room mic to add ambience (stereo messes too much with the phase in my small (ish) room I find).
    The MS will hopefully make the ambiance a little wider. A demo I found on Brainworks website certainly sounds like it.
     
  6. Markdvc

    Markdvc Administrator Staff Member

    Just to add one suggestion (Pete and Peter have really said it all). Try Omni instead of Cardioid as the pattern for the Mid microphone. You might like the results - I nearly always use this for any M/S recordings I do.

    kind regards

    Mark
     
  7. Pete Thomas

    Pete Thomas Administrator Staff Member

    Is there any advantage in having two separate tracks which are then bussed to the track with the MS dirmixer? I have always just recorded both mics direct to a stereo track with the MS dirmixer (as you say, mid to L and side to R)
     
  8. Peter Ostry

    Peter Ostry Administrator Staff Member

    Only if you want to process the two differently.
    (and of course if the two mics are not connected side by side)


    I also record to a stereo track but instead of the Direction Mixer I use the Brainworx bx_digital V2 which allows independent EQing for mid and side.
     
  9. Pete Thomas

    Pete Thomas Administrator Staff Member

    Ah that makes sense I can see why you would want to do that, especially if they are different mic types.

    But presumably when recorded on a stereo pair, it is the width slider which balances between the mid mic and side mic, is that correct?
     
  10. Peter Ostry

    Peter Ostry Administrator Staff Member

    Yes. When the Direction Mixer is switched to M/S, the width slider controls the level of the side mic.
     
  11. HKC

    HKC Senior member

    Hi again
    Thanks for the omni tip. That was also on Brainworks site with an audio file attached ao I was aware that it could be done. I was just trying not to complicate my question.
    As for the seperate eq for mid and side, that's probably a good reason to record to individual tracks instead of just one stereo. Uding that method would allow you to do just that before routing to the stereo channel-

    PS the pictures of the Logic channels, how come the channels say audio 1, 2 and 3. Here it says tracks 1, 2 and 3.....
     
  12. Peter Ostry

    Peter Ostry Administrator Staff Member

    It doesn't get more complicated if you choose another mic pattern. I'ts just a matter of sound. M/S was invented to keep 100% mono compatibility for stereo recordings. Therefore, with a typical M/S setup, you want to blend the mid and the side as good as possible.

    In a "real" M/S recording the side goes quiet if you switch to mono. You are left with the mid alone and this is the original idea behind M/S: No side, no phase problem. A cardioid in the mid channel may not be the best choice because the cardioid does not capture the whole room and in M/S, if you are too close to the source, the mono sound can get harsh and too direct compared to stereo.

    In a M/S configuration the relatively deaf backside of the cardioid has two effects: You emphasize the direct sound, which shifts the point of interest towards the source by suppressing a part of the room information. Second, you blend the beautiful sound of the figure eight partially with the poor sound of the backside of the cardioid which degrades the overall room sound.

    Of course this only applies if you are in a perfect room and don't mix the M/S track with other sounds. Today M/S is often just used as a "source + room" technique, not so much in the sense of the inventor. If you use M/S recordings together with other sounds, ignore the M/S police (who will certainly knock on your door) and feel free to experiment.

    Basically you can use any pattern for the mid channel. Omni gives the most natural room impression, cardioid delivers a stronger direct signal. If you have more patterns available, try all of them because the result depends on the room and the type of sound source. For single instruments the wide cardioid is my favorite because it is more gentle than a cardioid and not as "roomy" as an omni. Another option is the M/S setup with two figure eight microphones. You get a strong direct signal and too much room but sometimes this is what we want.


    I don't know, my Logic says "Audio 1, 2, 3" by default.
     
  13. HKC

    HKC Senior member

    Hi again
    Sorry I didn't explain myself very well. I meant not to make the question confusing. I think I understand the variations of the mid mic, I just didn't want to write "cardoid, omni, fig8" so I just wrote cardoid since that's the one that is most commonly mentioned in threads about the subject.
    I will most certainly try out both. I have a drumsession during easter which will unknowingly become my crash test dummies:)
     

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