Facebook social media iconTwitter social media iconYouTube social media iconSubmit to Reddit

An interesting phase problem in drum overheads

Using microphones in a stereo pair always raises a good question - are you SURE they sound right?


Here is an interesting problem pointed out to us by an eagle-eared Audio Masterclass student (for preference, you should download this 2 MB .wav file and audition in your DAW)...


It's a mix of bass drum, snare and left/right overheads. Do you hear any problems? Let's listen to the overheads in isolation...


Listen the the snare drum in the overheads. Does it sound centered in the stereo image, as it should? On a casual listening, there doesn't seem to be a problem. This is probably because of the relatively uncorrelated signals from the kit other than the snare. But when you concentrate your attention on the snare, it is clear that it is...

Out of phase!

Yes, one channel is inverted with respect to the other. This probably happened due to an incorrectly-wired microphone cable. They sometimes come like that bought new and it is always worth checking. The second most likely alternative is that the phase button was down and the engineer didn't notice. So if we invert the right channel (which is the one that is incorrect when compared with the signal from the snare drum mic), we get this in the overheads...


And with the bass drum and snare...


Problem solved!

P.S. 'Out of phase' is a commonly-used expression to mean that one channel of a stereo pair is inverted with respect to the other. 12 characters versus 66 makes it a useful shorthand.

By David Mellor Sunday March 10, 2013

Welcome to Professional Audio

Come on the Audio Masterclass FREE COURSE TOUR. A short series of tutorials to welcome you to the challenging world of professional audio. Learn more...