If you’re trying to get a home recording studio up and running, chances are pretty decent that you’ve already tried to record an acoustic guitar once or twice.
You might have been surprised by how lifeless a sound you got, or maybe you’re just looking for some other techniques to try to get that elusive “studio sound.”
There’s no magical answer, because different acoustic guitars behave differently, but there are several techniques that many studios use to get a decent quality acoustic sound.
The XY technique is, pretty simply, crossing the paths of two microphones (commonly a Shure SM57 or similar cardioid mic) so that their heads are right next to each other but at an angle from 45 to 90 degrees. You’ll want to use a good quality dynamic or condenser cardioid microphone, ideally a matched pair (two mikes of the same model that have been optimized for use with eachother). This cuts down on phase cancellation and makes the mikes sound better after panning.
You can also space a pair of microphones, which might make the stereo effect a bit better. Use the 3:1 rule, which basically means that your microphones should be at least 3 times the distance from each other as they are from the sound source; you’ll want the microphones about a foot to a foot and a half (depending on the mic) away from the guitar, with one pointed at the 12th fret and the other microphone pointing right below the pegs of the acoustic. Pan each microphone 30 to 45 percent in either direction.
Using a Large Diaphragm Condenser
Large diaphragm (over 1 inch) condenser microphones can be great for miking acoustic guitars if used properly.
You can simply set up the microphone a couple of feet in front of your guitar and begin recording, but as I’d mentioned earlier, truly excellent acoustic guitar sound comes from stero miking. You could double the signal, pan the two signals and EQ them differently, but you may find it easier to point a dynamic cardioid at the sound hole, slightly towards the fretboard, and then put the condenser at about ear level pointing down–and when I say “ear level,” I mean “right next to your ear.” This can get a really intimate sound, as if the listener is the performer, and that’s the sound we’ve always been looking for from an acoustic guitar.
Alternately, you can put the large diaphragm microphone in front of the sound hole and put the other mike at the 12th fret. Regardless, you’ll be doing a little less panning than with the other two methods, but be sure your signal sounds open and wide. The exception to this is if you’re recording acoustic guitar with a band or drum machine; in those situations, you may want to confine the acoustic to a smaller area, depending on the song.
The annoying truth is that, like with anything else, good recordings take a lot of practice. Try monitoring a guitar a friend is playing and move around the mikes a little until you find a sound you want, messing with effects, panning, compression, and EQ, and constantly comparing the sound you’re getting to the sound on classic recordings. With enough practice, you can find the perfect technique.