Stereo image in mixing an orchestra

Discussion in 'Orchestra' started by BobRogers, May 13, 2007.

  1. BobRogers

    BobRogers Well-Known Member

    Another amateur hour question. Recording my daughter's symphonic band as a favor to the band director (and my daughter). The director, Diana Love is retiring after many years. Here is an article on her.

    This time I'm using my NT5s as an ORTF pair and (for the first time) a pair of C414s as omni outriggers. Just transfered the files to my DAW and things seem to be in good shape. The outriggers were a huge improvement as you might imagine.

    Here is my question. Without any adjustment, my recording seems to put the stereo image slightly to the left side. Looking at in hindsight, this is at least in some degree a choice on her part in the placement of the instruments. (And it may be that once I've listened to the whole concert more carefully this won't seem as pronounced. Might be a function of particular sections being featured in the first two songs.) I certainly took no steps to mitigate this when placing my mics or setting levels. Do you take steps to center the image of a recording when the sound of the orchestra pushes slightly to one side?
  2. zemlin

    zemlin Well-Known Member

    I'm pretty certain I would, unless it was the nature of a particular piece.
  3. David French

    David French Well-Known Member

    Layed as played.
  4. Boswell

    Boswell Moderator Distinguished Member

    Once you are certain your channel gains (including microphone sensitivities) are equal and that your acoustic centre of the microphone array is the middle line of the orchestra, that's how you record it. Any off-centredness due to what instruments are playing at any one time is down to the music, and that should be represented in the recording.
  5. Cucco

    Cucco Distinguished Member

    I'm with David - If the horns and trumpets are on the left, they come out of the left speaker. I don't try to accomodate.

    If it were a session recording, I would try to rearrange the musicians (with the conductor's assistance and approval.) For live - play the cards you're dealt. If you try to shift the stereo image, it won't sound right. Your outriggers will tell the tale of the stereo picture - there's nothing you can do to change that.

    Boosting the right side of your ORTF pair will only throw things off. While the majority of the stereo information is brought out by amplitude differences, in ORTF, you're also getting your stereo information and its width from time differences in the mics, which means that some of the "center" information is identical. If you boost the right side, your center image will get very wierd.

    The only other option would be spot mics on the right side, but I certainly wouldn't do that.

  6. Simmosonic

    Simmosonic Active Member

    Some random, inconclusive and possibly conflicting thoughts, written under medication (!)

    I agree with the consensus here; assuming everything with my gear was correct (mics matched, gain matched, mics in the correct centre and so on), I'd leave it as it is.

    Having said that, at the end of the day if it sounds wrong to you then you ought to either find out why and fix it if warranted, or consult with the client. Your 'wrong' might be your client's 'vision'...

    But also, have you thought about *why* it appears off to one side? Is it actually the placement of the instruments relative to the microphones? Or is it possible that your ORTF centre pair were slightly skewed towards one side (by which I mean, not facing directly straight ahead, or one of the mics protruding further forward then the other?). It wouldn't take much to mess with the arrival times and off-axis amplitudes and cause an image shift.

    Or maybe the omni outriggers are messing it up; for example, the room is not symmetrical and so the outrigger on one side is getting different LF energy to the other (due to nearby walls or similar), shifting the image to one side.

    It could be worth auditioning the ORTF pair in isolation, and the omni outriggers in isolation. Perhaps the problem is in one pair only, and will be easier to fix.

    How is the width of the recording? Such shifts can happen if the image is too wide (ORTF pair too close?), and so a part of the music that focuses on instruments on one side of the stage tends to pull the whole image that way. If that's the case, narrowing the image a little bit might be all that is required.

    Just some thoughts, please don't take them personally.
  7. zemlin

    zemlin Well-Known Member

    This was the spirit behind my reply as well. I wouldn't mess with it for the sake of messing with it - only if it isn't right.
  8. Simmosonic

    Simmosonic Active Member


    In those situations, Waves S1 can do a nice job of pulling the image around a bit. It's amazing what it can do, although it is always worth ABing against the original to make sure you've actually made an improvement. Sometimes you have to choose the lesser of two evils.

    And also on this topic; many of the things that we fret and fuss over as engineers are not even noticed by the client - until we (or someone else) points it out to them. Sometimes an ignorant client is a happy client. :wink:
  9. zemlin

    zemlin Well-Known Member

    Adobe Audition also has good tools for playing with the stereo field. For one recording I setup to record Blumlein but later decided I would be better off mixing it as MS. I was able to rotate the field by 45 degrees and the recording came out quite well.
  10. BobRogers

    BobRogers Well-Known Member

    Thanks for all the helpful advice. As I say, I'm still feeling my way here - using this volunteer work as training. One of the reasons I posted was that I was not 100% confident that I had my levels and/or placement right. However, the ORTF and the outriggers show about the same thing separately, so I feel that things were set correctly. I am getting a new set of monitors tonight (happy birthday to me) so I've been putting off messing with the mix for a few days. My question was prompted by my initial quick listen when I was rushing through and marking songs. My guess is that the fact that the trumpet and horn sections on the left had a more prominent part in the first two songs put the idea in my head. But it seemed like an important question, so I thought I'd ask anyway.
  11. multoc

    multoc Active Member

    There's no such thing as a stupid question Bob, dont' worry, it was definatly warrented.

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