Source: prosoundweb.com
A balanced pickup can often be acheieved by placing the mic (or x/y sterio pair) at a point slightly off-axis and above or below the sound hole at a distance of 6 inches to one foot [pg.152]. Now, there is no "right" or "wrong" microphone or placement for miking up an acoustic guitar, but the placement of the microphone can play a roll in the sound you are trying to acheive, as the diagram above shows. The farther away you place a microphone to the guitar, the more ambiance sound you will pick up, and the closer to the sound hole you place the mic, the more lower frequency or "bassy" sound will be picked up.