How to Record Acoustic Guitar Using the M/S Mic Technique
Today we’re going for more of an esoteric mic-ing technique.
This is more for a solo acoustic guitar or acoustic guitar and voice.
It’s really, mainly a stereo effect so you wouldn’t really use it for recording something in a full band track, because you probably wouldn’t even notice it.
But if the feature is the acoustic guitar, this is a very nice technique for a beautiful stereo effect, very realistic. It’s called the M/S mic-ing technique. You need two fairly high quality microphones. We’re using two Neumann U87s here. The bottom one is set to cardioid pattern, so it’s picking up just directly towards the acoustic guitar. The top one is set to a figure of eight pattern. I’ll show you later how that get’s mixed on a console or in your computer so that the top mic is actually put out a phase, it’s brought up on two channels, and the phase is put out on one side, then that’s mixed in with the cardioid mic. Usually the cardioid is predominant because that’s the main sound and this just gives it a wide stereo effect.
In your DAW you’ve recorded the two mics on separate tracks. You have the cardioid mic on the top track, the figure of eight mic on the bottom track.
Now the first thing you have to do is duplicate the figure of eight mic track to another track.
And then, put one of those tracks out of phase. Probably the one you’ve just duplicated.
Ok now, pan those 2 channels left and right. And then the cardioid mic down the center.
Play the take, and remove, actually, pull the cardioid mic all the way down. And what you’re left with is an acoustic guitar that sounds very out of phase. And It’s very disconcerting sounding.
Now gradually move that fader up until you start to hear the direct sound and the out of phase part, the annoying out of phase bit goes away. And you get it to the point where it’s not mono, but you have a real pleasing stereo. There’s just a spot right in the middle there where the cardioid will be predominant over the figure of 8 mic.