What’s the best way to record an acoustic guitar? When we’re listening to someone playing guitar in a room, we’re often doing it from a distance. If we’re playing the guitar ourselves, we have a unique close-up perspective and can even feel the vibrations of the instrument in our body. When it comes time to translate either of these listening experiences to a recording, it can be difficult to settle on a technique that checks all the right aural boxes, particularly with one microphone.
Using just one microphone, it can be difficult to find a balanced sound that captures the full instrument. If you pull back too far, you capture the full instrument, but lose definition. If you push in too close, you tend to capture too much of one component of the sound. Over the years, I’ve found that using multiple microphones is the best way to translate those in-person acoustic experiences onto a recording. As always, these decisions should be made thinking about the song and the specific instrument that’s being recorded.
The Guitar’s Role in the Song
One of the first choices you’ll have to make when recording acoustic guitar is which specific body type to use. Acoustics come in a variety of shapes and sizes. Each has sonic characteristics that need consideration as these may impact your microphone selection and placement.
When choosing the instrument, think about what role the acoustic will play in the song and in the mix. For singer-songwriters, or sparse country & western tunes, the acoustic may form the backbone of the entire track. Alternatively, in a rock production, you may find that the acoustic plays more of a supportive role, and its percussive qualities are just as important as its harmonic qualities. Think of the sounds required for the part and pick an instrument that is best suited for that sonic job.
Setting Up Your Two Microphones
When choosing and setting up microphones, I find it’s best to think of the total sound coming from the instrument, then break that down into individual elements. Consider the different sounds the guitar will make and where they originate on the instrument.
In the case of an acoustic guitar, there are two locations that I like to zero in on for positioning a two-mic setup.
The first location is found behind the bridge, capturing the largest part of the body. This is where you’ll typically get the warmth and volume. For this area, I like to use a large-diaphragm condenser such an AKG C414. If you’re looking to add a little extra harmonic content, you may want to consider a tube mic such as the Mojave MA-200 or Neumann U67. For placement, consider starting about 6” to 12” from the guitar. The farther out you go, the more low end you’ll lose. As you angle your mic, you’ll find that you’ll get the most volume if you point it toward the soundhole. As you rotate the mic in either direction, listen for the subtle (or not-so-subtle) changes in volume and tone.
When setting up the second microphone, I concentrate on where the neck meets the body, up to around the 12th fret. This will be a bit brighter than the first location and offers more articulation and clarity. This area still has great midrange and lower-frequency content as well, and it can be a good starting point when you’re just using one microphone. For this location, I like to reach for a small-diaphragm condenser, such as the Neumann KM 84 or KM 184. I’ve also had nice results with my Mojave MA-100, a tube mic. These mics tend to accurately pick up the transients of an instrument and can be useful in capturing the clarity of an acoustic.
If you’re looking to control the sound of the second microphone a bit more, you’ll find that moving the mic away from the body and up the neck will produce a thinner sound, while inching the mic down to where the fretboard overlaps the body will blend in more of the midrange and body of the sound.
Pairing a Large-Diaphragm Condenser With a Ribbon
A newer approach that I’ve recently grown to enjoy is pairing a large-diaphragm condenser mic with a ribbon mic. Like the prior example, we’ll utilize one mic for the body of our sound and one mic for the clarity and presence.
With these two mics, I’ll first set the condenser up in that well-balanced, “around-the-12th-fret” area, adjusting to find a good overall tone that would work by itself. Then, I’ll take my Royer R-121 ribbon mic and place this right over the MA-200 large-condenser capsule. I set it up so that the bidirectional null of the 121 is facing straight toward the guitar and the two sides of the mic are facing sideways down the length of the instrument. You can think of this like the same mic positioning that might be used for a mid-side stereo placement, but in this case, I use them for a simple mono blend.
What’s interesting about this combination is that having the bidirectional ribbon mic facing up and down the instrument really gives a sense of the sound the instrument projects. This, combined with the focus of the MA-200 near the 12th fret, can give a cool depth to the sound. The best way to describe it would be “Hi-Fi,” and you need to be mindful of it getting lost in a dense production. It may also be a little too pretty for a track that needs some edge. For that, you’ll want to start looking for a mic with a strong midrange character to add to the multi-mic setup.
Thinking About the Acoustic’s Midrange
To add some midrange energy to an acoustic recording, reaching for a dynamic mic can be just the ticket. I love having the humble Shure SM57 on hand for this application.
When using an SM57, I’ll supplement it with a large-diaphragm condenser, placed in a well-balanced spot near the 12th fret. Then, I’ll place the 57 in this same area, to the side of the condenser, so that the 57 is closer to the guitar body. Now, you’ll be able to bring the 57 up in the blend to add some energy and scrappiness to the sound. I like starting with these mics placed close together in order to ensure that they have a good phase relationship, but it can sometimes be interesting to move the dynamic around to find a location that’s particularly “midrangey.”
Another interesting choice for this application is the Beyerdynamic M 160 ribbon mic. This hypercardioid ribbon has a distinctive midrange character and can be a cool alternative to the SM57.
In experimenting with a midrange-focused mic, you may find that it works great on its own, particularly in a denser mix where the acoustic needs to occupy a smaller space. A single SM57 in front of the acoustic can sit nicely in a mix. You may also find good results with an SM57 over the shoulder of the player’s strumming hand, pointed down at the body of the guitar. I’ve found that this position offers a more balanced sound than out in front of the guitar. It’s worth experimenting with both as a position for a single-mic approach, or as a position in a multi-mic setup.
Using an Acoustic’s Direct Output
If the guitar you’re recording has a direct out, this might also be worth recording. I typically don’t care too much for a DI guitar sound by itself, but it can be a useful sonic ingredient to tuck into a microphone blend to add detail to the sound. Also, a DI can be a good source to record if you are tracking both an acoustic and a vocal at the same time, or tracking an acoustic live with the basic rhythm tracks. Having that bone-dry acoustic signal with no leakage might be just the thing you need in your blend. The isolated DI signal can also be a fun sound source to get a little weird with. Consider using the DI as a send to a guitar pedal or to some kind of effect to pull into the final mix.
Thinking About Stereo
I’m not the biggest fan of close-miking acoustics with traditional stereo techniques. I often find that when you’re close miking, having two mics with contrasting tones is more useful than a matched stereo pair. Matched stereo pair or not, I like to experiment to see if just slightly panning any of my mic combinations leads to a cool sound. I try to avoid hard panning them, since I feel it tends to give a strange disembodied sound, but slightly panning them out to the right and left can feel nice and a add little bit of space and depth. This can be especially helpful in a sparse track as it can help make some room in the center of the mix for the vocal.
Where I do like to reach for a pair of matched mics is room miking. I’d typically only include a room mic on an acoustic if I knew the song was going to be a sparse production (i.e., guitar and vocals). In this case, adding some room ambience can be nice but, keep in mind, sometimes intimacy is key, and adding too much ambience or room tone can fight against that feeling. Let your ears be the guide.
Acoustic guitars are an interesting place to experiment with microphones. Acoustics can play such varied roles in a production and, depending on your mic choice, you can really highlight different parts of an acoustic’s tone. Use all these tips as a general guide and don’t hesitate to substitute any mic into any of the above-mentioned positions. You may end up with some great sounds!