I have always been interested in finding new and inventive ways to record the ever-elusive acoustic guitar. Over the years I have developed a few "tried and true" methods, which seem to repeatable in a variety of situations. Some are very basic techniques that have been used by thousands of artists and producers, and others are techniques that I have discovered on my own from experimentation.
It is important to note that I will reference three different acoustic guitar pickups in this article. All of my guitars have three different pickups, each with its own output jack. With this setup I can send each signal to any path I want, live or in the studio. I use a magnetic soundhole pickup, a soundboard transducer, and a piezo saddle pickup. In my opinion, there has been no acoustic pickup manufactured to date that accurately reproduces the sound of the guitar. The reason for using three different pickups is to be able to focus on the strengths of each and none of the weaknesses. Magnetic acoustic pickups have a naturally warm and powerful low end, but sound muddy and flat in the mids and highs. Soundboard transducers have a beautiful sparkle on the high end, but sound boomy in the bass. Piezo pickups have a tight and focused midrange, but sound brittle in the highs. Basically, what I like to do is boost the "good" frequencies of each pickup and roll off the "bad".
For purposes of this discussion, I will split recording tasks into two broad categories: Recording guitar without drums/percussion and recording guitar with drums/percussion.
If I'm recording solo guitar music, or solo guitar with the addition of one or two other instruments, such as I did on both "Consistent Variation" and "Sticks & Stones", I tend to favor using a matched stereo pair of small diaphragm condenser mics. Since each guitar and recording space is different, a discussion of exact placement isn't possible. In general, you should start with a basic placement of one mic near the neck to body joint and another near the bridge on the body. After initial setup you will just have to play with placement until it sounds full and natural, without any "booming" in the bass.
As for effects, I always record dry to tape, but monitor with a reverb which approximates the final reverb we will use in the mix. This is really important, since the reaction of the reverb will totally affect the way you play and your sense of space and timing. In most cases, the mic signals will be panned hard left and right, respectively. Occasionally, I will also add some pickup signals to the recording. Most often it will be the magnetic pickup, although in rare cases I will use the piezo and soundboard transducers as well. The magnetic pickup can be useful in situations where you want to overemphasize the low end. If you try to do this by adding EQ to the mic signal, it ends up turning the mix into mud by ruining the clarity. Adding lows with the pickup won't affect the mic signals, and if used sparingly, won't draw attention to the sound of the pickup.
An extreme case of using a variety of different signals in recording a solo guitar piece is the tune "Trance Dance" on the "Sticks & Stones" record. For this tune, we put a pair of vintage Neumann 256's on the guitar, sent both the Sunrise and SBT signals to a Trace Acoustic preamp and then to the console, and then sent the piezo pickup signal to a 200 watt Trace Acoustic amplifier in an isolation room. Here, we put a pair of Neumann KM-84's in close, and an AKG 414 in the far end of the room as an ambient mic. All in all, we ended up mixing 7 channels of different signals for one solo guitar part. The result was a sound that was less than natural, but undoubtedly huge. In summary, when recording solo guitar, start with a pair of really good microphones, and then add pickup signals if you need to in order to get the desired effect.
The addition of drums and percussion actually makes the whole process of recording acoustic guitar a totally different animal. I'll use my upcoming fusion record "Speak" for illustration purposes, since there are drums on most of the tracks. Although Rod doesn't play particularly hard as far as drummers go, we still had to find new ways to record to make the guitar stand out.
The biggest problem to contend with is that since acoustic guitar is percussive by nature when played rhythmically, how can you compete with the snare and hi-hat to make the guitar occupy its own space? Here's how we did it: We cut some direct guitars first by taking a signal from each of the three pickups patched through three separate Trace Acoustic preamps and giving them each their own board channels. I played the main rhythm part once and panned the piezo and soundboard transducer channels hard left. The magnetic pickup was panned in the center since it represents only low frequencies.
Next, I overdubbed an exact replica of the rhythm part again, this time panning the piezo and soundboard transducer hard right, with the magnetic pickup again in the middle. Finally, I overdubbed a third replica of the main rhythm part with my Froggy Bottom guitar miked close with a pair of vintage Neumann 253's, but no pickups. While one would think that all this doubling would create unpleasant chorusing effects, the end result is the impression of one giant guitar. You just have to be careful to play the parts as exact and tight as you can to avoid time-based artifacts. Kip made me do a bunch of them so we could pick the tightest takes more easily. From there, if the tune had a separate melody played by guitar, as in the song "Trades", I simply overdubbed that with the Froggy using microphones only. Using all the parts together allows you to form an absolutely giant rhythm sound which can be EQ'd to oppose the drums so that they compliment each other without canceling one another out.
Many people have written me asking if it is possible to achieve a similar result with compression. I would advise against this simply because front-end compression is going to kill the overtones. On "Speak", the only guitar compression we used is on the 2-track mix to fatten the overall sound. We never used compression as an insert on any guitar channels. When in doubt, double it. If that isn't enough, double it again. Keep doubling until you can't hear the snare anymore without turning it up, then you'll know you've got enough.
For samples of the recording techniques discussed in this article, you can visit the MP3 page on my site and download clips from each of my instrumental acoustic albums. There is a pretty good range of material represented from each of the two camps, so you can hear and compare the differences. I hope you find something of interest which will inspire you to try some of the recording techniques offered here. Please feel free to email me with any comments, questions, or ideas of your own.