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ORTF vs XY

Discussion in 'Microphones' started by audiokid, Feb 8, 2011.

  1. audiokid

    audiokid Staff

    What are the pros con between ORTF and XY?

    • How do you know which config to use? Is one better for solo, quartet, choirs, orchestra?
    • How does crossing XY change the imaging vs the opposite in ORTF?
    • Does X have to be above Y (or vise versa) and why?
    • Do you use the same Cardioids for XY or ORTF or a?
    Thanks!
     
  2. TheJackAttack

    TheJackAttack Distinguished Member

    ORTF gives you a "wider" spread to the sound. Austrian broadcasting has used this successfully for good reason and of course there is the NOS variant as well. The danger for these techniques if it can be called a danger, is in small ensembles one can lose a little of the center image.

    XY is sort of the cookie cutter coincident stereo technique. XY is easily manipulated to the ensemble size and spread even though technically it's a 90 degree pattern. XY inevitably comes across more narrow in the aural field and as a result is slightly more mono compatible. Some folks use hypercardioids for ORTF (AT4053's come to mind) but most folks use quality normal cardioids for either pattern. The irony to me is that XY is half of a Blumlein array but I MUCH prefer Blumlein as a stereo technique. Either microphone (X or Y) can be on top. It goes both ways ^_^ Same with Blumlein. In MS I normally have the Mid cardioid on the bottom but it doesn't have to be. You aren't sent to the third circle of hell if you swap it out.
     
  3. audiokid

    audiokid Staff

    Thanks John, that's was very helpful. It makes more sense now that I understand the difference between the two in imaging. Even though they are both 90% the space apart in ORTF is enough to make it wider.

    What does ORTF mean?

    I'm guessing XY and flanks is more common together?
    ORTF and a center is more common?

    Am I getting it?
     
  4. TheJackAttack

    TheJackAttack Distinguished Member

    With ORTF (120 degree spread) you don't use a center. XY (90 degrees same as Blumlein) is pretty well matched to pick up the center strongly. Flanks are used any time you think the wings have aural information that is perhaps too far forward of the mic pattern "center" to be picked up from either the X or the Y mic. A large ensemble is often better served by an ORTF array since it picks up a wider field of coverage. Small ensembles often "hide" in the center of an ORTF array so XY or Blumlein would be a better pattern.

    Office de Radiodiffusion Télévision Française.
     
  5. audiokid

    audiokid Staff

    ah yes, I said that wrong. I was thinking that they both look like they are pointing the same and the only difference was crossing each other but he ORTF is actually 30 degree's wider?
     
  6. audiokid

    audiokid Staff

    So the first Choir video sounds like ORTF?
     
  7. TheJackAttack

    TheJackAttack Distinguished Member

    Right. ORTF is not only at a 110-120 degree angle but the microphones themselves are 17cm apart. In XY the capsule are as close as you can get without touching at a 90 degree perpendicular placement. NOS (Belgium radio technique) is 90 degrees pattern but spread apart 30cm. The easiest way to set these patterns up quickly is to have some poster board with a pattern drawn out. Then the only thing you have to eyeball is the height and angle downward.
     
  8. TheJackAttack

    TheJackAttack Distinguished Member

    Sure On This Shining Night is ORTF and the O Magnum Mysterium is the ceiling hang: either three spaced omnis L-C-R or a wide decca (forward C, rear L-R wide pair).
     
  9. TheJackAttack

    TheJackAttack Distinguished Member

    $*^t. Got it backward. Magnum Mysterium is ORTF at the stage front on the stand. Shining Night is the hanging mics.
     
  10. audiokid

    audiokid Staff

    When you say too far forward, are you saying away, or weaker? I'm a bit confused with that term but I like it :). I'm thinking flanks are intended to capture the wings or far left/right?
     
  11. TheJackAttack

    TheJackAttack Distinguished Member

    In a Decca setup, the C mic is in front of the L-F. It looks like an upside down capital T. _|_ If your L-R pair are spread apart two meters the center should be closer to the stage by one meter. An easier way to think about it is go equal distant from your center point. Left one meter, right one meter, forward one meter. Sometimes the L-R is 1.5:1 ratio. I wouldn't worry about Decca. You're best bet for these choirs is either Blumlein or ORTF or A-B spaced pair. Decca is really for large instrumental ensembles and should be partially over the musicians themselves.
     
  12. audiokid

    audiokid Staff

    Shinning Night would be all be omni's
     
  13. TheJackAttack

    TheJackAttack Distinguished Member

    That would be my guess as well for Shining Night.
     

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