Welcome back to Gibson’s quick-hit column on techniques for recording guitars. This time I’m going to discuss some basics for recording acoustic guitars, offering a few pointers that are largely very simple but can help you achieve dramatically improved results in many home studios. This is another two-parter that will investigate some more complex acoustic miking techniques next time out.
The first installment of this series discussed the three main types of microphones used for recording electric guitars—dynamics, condensers, and ribbons—and these are all used for recording acoustics, too. Condensers have traditionally been the most popular mics to capture acoustic guitars because of their sensitivity and broad frequency range, which usually includes more prominent and “shimmery” highs than the other two types, something many artists like to hear in their acoustic sound. Thankfully, decent condensers are a lot more affordable than they were just a few years ago. The renewed popularity of some ribbon mics has led many recordists to use them on acoustics, too, the Beyerdynamic M160 being a perennial favorite for guitars and other stringed instruments too. Standard dynamic mics such as the seminal Shure SM57 and SM58 and mics based on those formats tend to be less flattering than condensers, but if that’s all you’ve got handy you can still get perfectly good results from them with careful use. In some cases, when you want to capture a thumping, midrangey rhythm part without intrusive highs that might get in the way of cymbals or other instruments, a dynamic might be your best bet anyway. Whichever type you have available to you for recording acoustics, keep these basic pointers in mind:
Condenser mics are generally very sensitive and will usually be placed between 6" and 18", or even further from the guitar, in standard front-miking techniques (further still in more creative or “ambient” techniques).
Dynamic mics are less sensitive than condensers, and will need to be positioned closer to the guitar, in relative terms, to capture satisfactory volume levels.
Ribbon mics are also less sensitive than condensers, but many types also over-accentuate the lows if placed too close to a sound source (this is called “proximity effect,” which can affect almost any standard cardioid microphone, but tends to be accentuated in many ribbons). For this reason, many ribbon mics also need to be placed 10" or 12" from the sound source. Because they are a type of dynamic mic, they are not especially sensitive. You will also need a good, clean sounding microphone preamplifier with high gain levels to boost the signal adequately, without inducing too much noise, in order to get satisfactory results.
As with miking guitar amps, the best way to find the right place to put your acoustic guitar mic is to listen in a number of different positions to the sound your guitar produces, record a little of it with a mic placed there, and listen back. One important tip at this point, however, and perhaps the most important thing to get down from the start, is that you should not place the microphone pointing straight into the sound hole. Do this, and you capture a woofy, muddy, booming sound that is pretty loud, certainly, but not really representative of your full acoustic guitar tone in any other way. For beginning recordists this can take some getting used to, because of course whenever you take your guitar out to an un-amped acoustic gig the sound engineer points an SM57 right into the soundhole. Even in live performance this doesn’t capture the most flattering acoustic tone, but it does tend to capture the most volume from an acoustic in a live situation, and that’s a compromise that we are often willing to live with in a small club or coffeehouse gig.
An acoustic guitar’s sound isn’t produced from the sound hole alone, and in fact that is really just the point where sound reflected from the backside of the top and off of the back of the guitar escapes the guitar’s body. A lot of the tone is produced in the area around the bridge and the broad portions of the lower-bout section of the top, while other frequencies are produced in the region of the upper bout where the fingerboard joins the body, and the sound coming off the back of the guitar has its own tone, too. Usually you will want to use a technique that captures a blend of a few or all of these sounds.
One of the most popular traditional studio techniques for recording mono acoustic guitar involves placing a microphone at around the 12th fret, a few inches away from the fingerboard, and aimed back toward the end of the fingerboard (at the body end), but not into the soundhole. This captures a bright, lively acoustic tone with a good, rounded body and some string sound for added jangle.
Another position that captures a full, woody, and somewhat less jangly tone is found by pointing a mic at the guitar’s top in the region of the lower bout just below and behind the bridge. Moving the mic further down and away from the lower end of the guitar and aiming it at the edge of the body, where the top meets the side of the guitar, can produce another interesting tone, one which is usually heard as being a little more edgy and cutting.
Experiment with these and any other positions you can think of, and see what works for you. Again, as with recording guitar amplifiers, the “best” sound won’t be a universal, but will depend on what works when you hear the guitar in the full mix, if it’s a full band track. Next time, we’ll check out some more unusual mic placements, as well as some stereo and multi-mic techniques.
For helpful information on miking and recording guitars, click here and here!