Yo modus. Generally, X-Y, also known as coincedent stereo recording, is done with 2 small diaphragm cardioid mics. Picture the setup as a wide letter "V", with the capsules of the mics either on top of one another or side by side, as close as they can be to each other without touching. Usually the angle between the two mics is a little greater than 90 degrees, say 110d.
Phase problems shouldn't occur, as the capsules are so close together that the sound reaches tham pretty much at the same time. Check
www.sound-room.com and click on octava microphones. Then click on "matched stereo pairs", which will show you a pair of Octava MC012's in Sabrasom shock mounts in coincedent arrangement.
In theory, at least, the pickup patterns of the two mics overlap like the fields of the two halves of a pair of binoculars and come into focus, creating a clear stereo image. Generally, this works out well backed off a little from an acoustic, say 2-4'. It also works really well for a larger source such as a band or choral group, backed off 20-30'. With the Octavas in particular, I found that a dreadnought can actually move enough air to cause them to pop, and putting a pop filter in front of them can be a good idea, which surprised me.
I usually back them off until one mic is pointed at the 12th fret and the other at the bridge. I often combine the pair with a larger diaphragm cardioid mic, over the left shoulder angled down toward the upper bout, or an omni backed off, as an ambient mic, to pick up the whole room. It's even feasible to augment the stereo pair slightly with a direct signal from a good pickup, if your guitar has one, into a pretty good preamp. Hope this helps.-Richie
