Three stereo miking secrets guaranteed to make your acoustic guitar tracks shine.
Ask five engineers how they approach recording acoustic guitar, and you may very well get five different answers, if you get any at all, that is. While many factors influence an engineer's choice of recording techniques -- the character of the instrument, the style of music, the player's personal tonal and dynamic signature, and the recording environment -- some engineers prefer to keep their approaches a trade secret. But despite all the possible permutations of instrument, style, player, room, and ego, for most seasoned engineers the real secret to recording an acoustic guitar is stereo miking -- plain and simple.
Sure, if it's just "spaciousness" you're after, you could record an acoustic guitar in mono and fold in some enthusiastic stereo processing. Or if you're hankering for a dramatically textured sound, you could try combining a microphone with an acoustic guitar pickup. If depth and accuracy are what matter most, however, you'll find that stereo recording with two microphones is an exceptionally reliable way to record full-bodied, realistic-sounding acoustic guitar tracks.
Let's take a look at three of the most popular techniques, and also examine the questions of microphone choice and mono-compatibility. As you'll find, stereo recording can be a complex art, since the interaction between the two mics will determine many aspects of the sound -- including tone, image, and mono-compatibility. But like any art, you'll also find that practice makes perfect. So whip out those mics, pull out that guitar, and give these tips a try: You'll hear the difference.
Three Surefire Techniques
In most cases, you'll want to use a pair of cardioid (unidirectional) mics placed close to the instrument. Close-miking -- approximately six to 12 inches from the guitar -- is used in most pop and other contemporary recordings that feature acoustic guitar.
Cardioid mics are generally best used for close-miking guitar because they exhibit less bass proximity effect (or bass boost) than other directional types when placed close to the sound source. And we all know that acoustic guitars can sound boomy if miked incorrectly.
Let's explore three common approaches to stereo miking and acoustic guitar. Each of these techniques has been used on countless hit records. Be sure to check out the corresponding audio links, and of course, consider these as starting points for your own creativity. After you've mastered each one, feel free to experiment with your own variations on each method.
Spaced Pair, Version A
Two mics are placed apart from each other at the same approximate height, one pointing at the 12th fret of the guitar and the other at the bridge.
With this approach -- as with any miking technique that uses two or more mics that are spaced apart from one another -- always be sure to follow the "3-to-1 rule." According to this rule, the distance between two mics should be at least three times the distance between each mic and the sound source. This keeps phase cancellations to a minimum, resulting in a smoother sound that also translates well to mono. So, for instance, if you've got each mic seven inches from the guitar, the 3-to-1 rule mandates that you spread the two mics at least 21 inches apart from each other. (One of a few exceptions to the 3-to-1 rule is with the X-Y technique, as described below