phase experiment

So a while ago, I was jamming out on my trumpet trying to play along with stuff. I wanted to practice recording it because i know at some point i will want to. Playing with headphones proved to be a pain in the ass. So I had an idea. If I just play the mix through the monitors and record my trumpet like that, then record on another track, just the mix without the trumpet, being careful not to move any faders or the mic, then flip the phase of one of the tracks, making the background dissappear!!

I gave it a shot and found that I had some success with it. Of course it wasn’t perfect, but it significantly reduced the level of the mix in the background. It might not always be the best solution, but I think its worth experimenting with. There will be some times when it is the way to get the best performance out of a singer, horn player or whatever with the least amount of background noise.

You might find that with better equipment some problems climb out of the woodwork, but I’m all for exprerimentation !

If it works - do it.

Some motorcycle intercomms actually works using this principle. Every system have two mic’s built into the helmet. One picks up only the ‘noise’ inside the helmet and the other one is very close to the source (mouth mic very close or mic against the bottom of the jaw). It does this phase cancellation thing on the fly and you end up a SIGNIFICANTLY clearer signal on the other side.

Keep experimenting !


There are “noise cancelling” headphones, too, that use this principle. I’d guess they might come handy during long flights…

And yes, if you see Grateful Dead video clips from the seventies you might notice their weird looking two-heades microphones. As they had their entire PA behind the players (the legendary Wall of Sound) they needed to use noise cancelling mics. The lower capsule was wired with reversed phase. You’d sing to the upper capsule.