xy phase problems?

green dc · Post by **green dc** » Tue Jul 14, 2009 9:24 am

hey all, anyone ever run into phase problems w/ xy as drum overheads? this is the first time i'm experiencing this, could it be bad wiring? the phasey sound is staggering when left as is, but as soon as i flip the phase on one mic, the sound fills out fantastically, and sounds normal. seems counterintuitive. curious if anyone has had issues w this before.

drumsound · Post by **drumsound** » Tue Jul 14, 2009 9:29 am

If you have the capsules that close, in a true XY, you got a bad cable somewhere, or maybe the mic needs rewiring.

chris harris · Post by **chris harris** » Tue Jul 14, 2009 9:31 am

drumsound wrote:If you have the capsules that close, in a true XY, you got a bad cable somewhere, or maybe the mic needs rewiring.

yep.

Ryan Silva · Post by **Ryan Silva** » Tue Jul 14, 2009 10:52 am

Well the good news is it sounds like something was wired 180 deg out of phase, so this time all you have to do is flip phase.

cgarges · Post by **cgarges** » Tue Jul 14, 2009 12:48 pm

Are you using a pair of mics or two different kinds? Some mics are wired with pin 2 as the positive and some are wired with pin 3 as the positive. Exactly what you're describing will happen if you use two mics with different output wiring.

Chris Garges
Charlotte, NC

Brett Siler · Post by **Brett Siler** » Wed Jul 15, 2009 12:42 am

I have a pair of Oktava MK319s that are wired with opposite polarities. It's kinda a pain but not a huge deal.

dubh dubh dubh · Post by **dubh dubh dubh** » Fri Jul 17, 2009 1:46 am

yessir, sounds like something is wired out of phase, OR the x-y is just the slightest bit off.. doesn't take much distance in any of the 3 dimensions for one mic to end up opposite polarity of the other. Heck, drummer or whomever coulda inadvertently bumped a stand, just moving it a quarter inch, and hello hollow-town!

CedarSound · Post by **CedarSound** » Fri Jul 17, 2009 11:25 am

hello hollow-town!

Nice.

farview · Post by **farview** » Fri Jul 17, 2009 3:59 pm

dubh dubh dubh wrote: the x-y is just the slightest bit off.. doesn't take much distance in any of the 3 dimensions for one mic to end up opposite polarity of the other.

This is impossible. There is no distance that the mics can be placed where the POLARITY will be opposite. Only the frequency that corresponds to the distance will be 180 degrees out.

Time and polarity are not related.

Vogon · Post by **Vogon** » Sat Jul 18, 2009 10:23 am

Yep. You'd have to have a point for the second mic where all frequencies were exactly out of phase with the first. Impossible in practice.
Take just an 80Hz bass frequency - (I think) that would require over 7 foot between mics. Every freq above will cancel at progressively shorter lengths.

Flipping the polarity on a second, non-coincident mic only ever reverses the existing phase cancellations - which may or may not "sound better' in context.

dubh dubh dubh · Post by **dubh dubh dubh** » Sat Jul 18, 2009 7:13 pm

farview wrote:
dubh dubh dubh wrote: the x-y is just the slightest bit off.. doesn't take much distance in any of the 3 dimensions for one mic to end up opposite polarity of the other.
This is impossible. There is no distance that the mics can be placed where the POLARITY will be opposite. Only the frequency that corresponds to the distance will be 180 degrees out.
Time and polarity are not related.

vogon wrote: Yep. You'd have to have a point for the second mic where all frequencies were exactly out of phase with the first. Impossible in practice.
Take just an 80Hz bass frequency - (I think) that would require over 7 foot between mics. Every freq above will cancel at progressively shorter lengths.
Flipping the polarity on a second, non-coincident mic only ever reverses the existing phase cancellations - which may or may not "sound better' in context.

AH sorry fellas... I WAS waaay oversimplifying and mis-using the vulgate, as it were... please forgive an auld insomniac for typing without brain engaged!

Yep. I shoulda just said that it doesn't take much of a mis-alignment to make things MAYBE sound not so good. Your mileage may vary, side effects may include rectal seepage and tinnitus...

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xy phase problems?

xy phase problems?

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