drum overhead phase cancellation

C

Conrad Josepi

New member
Hi all,

While I'm doing the mixing of my project, I have noticed that cymbals that appear in the center of the mix, because they are being picked up by both everhead, seem to dissapear. Cymbals that are way to the left or right seem to be quite clear, but the ones inthe center seem to lack body.

I suspect that this is the result of phase cancellation.

I am considering trying to invert the phase on one of the ohead tracks to fix this problem.

Are there any consideration I need to make when doing this? Will I ruin something else by making my middle cymbals clear?
 
If you can do it with your mixer or in software, just go ahead and try it on a mix. You shouldn't lose the phase of the original track, right? Try one and then the other. By the way, you're probably right that it is a phase problem, and you're on the right track to solve it. You can minimise phase issues by the old 3:1 rule - place the mics 3 times farther apart than they are from the source. Or by using the X/Y configuration.
 
Although Larry, in a X-Y pattern you still need to phase reverse one of the mics. Otherwise you still wind up with cancellation.

Ed
 
Thanks, Sonusman, are you certain about needing to reverse one? It doesn't mention that in the section on XY micing in Modern Recording Techniques p.121 about 1/2 way down.
 
I've never heard of that. In fact, that's the whole point to stereo recording techniques; to prevent phase cancellation. Of course, different techniques give you different results having to do with the stereo image, mono capabilities, etc. For drum overheads, my favorite is ORTF configuration.
 
It's to my understanding that the X-Y
have the least amount of phase problems when you set them up with the capsules as close as they can be with out touching
overlaping at a 90 angle.

This way they hear the sound source nearly simultaneously thefore receving the sound wave in the same phase
 
I am not sure what it says in any of the recording books, but when I don't phase reverse one of the mics the sound sure thins out and the center stuff get washed out, exactly the symtoms of phase cancellation. So, if not reversing one is working for you, well, have at it. I am not saying that it is wrong, but hypothetically there are problems with not doing so. In the highest frequecies not reversing while X-Y micing would be no problem. But the low end is nowhere as directional, and of course takes time to fully develope. Thus, phase cancellation is definately going to happen in lower frequencies in a X-Y without reversing the phase of one of the mics.

Give it a try.

Ed
 
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