If you’re doing home recording, one of the main instruments you may be using for accompaniment is the acoustic guitar. Learning the basics of acoustic guitar recording requires time to experiment a bit to find your instrument’s sweet spots for micing, and also understanding some essentials with regard to your guitar and recording environment. We’ll use the most popular dynamic mics that many musicians rely on for gigs, the venerable Shure SM-57 and 58, to show how to get a good recorded sound from your acoustic guitar. We’ll also recommend two affordable condenser mics that can help you take your guitar’s sound to the next level.
Speaking in a 2004 interview, Grammy-winning engineer Richard Dodd, whose credits include a wide range of acoustic guitar-playing artists such as the Dixie Chicks, Tom Petty and the Heartbreakers, The Traveling Wilburys, Wilco, and George Harrison stated, “most great rock records have an acoustic guitar even though you may not notice it.” So how do you go about getting your guitar sounding good when you’re making the recording?
Before we head into the studio, there are a few basics that will help you to get the most out of your acoustic guitar. First, be sure to put a fresh pair of strings on the instrument before your recording date. Oxidation occurs normally and deadens the sound of your strings, to the point where your guitar isn’t able to produce the full sound of which it’s capable. Personally, I’m partial to the Nanoweb-coated strings put out by Elixir, because they maintain their new tone longer and seem to produce a bit less finger noise which can become distracting when recording.
Next, be sure you are comfortable with your performance location before starting to record. I prefer to record standing up, using a strap, as I feel my posture is more balanced than sitting on a stool. If you’re recording at home, try your living room area, because it offers a mix of absorptive (carpet, furniture, curtains, etc.) and reflective surfaces (walls, windows, ceilings, etc.). I have a reliable tuner handy to quickly confirm intonation between every take, to avoid nailing the perfect performance only to find that my “B” string had gone flat.
Before you get out your microphone and start to experiment, try the technique that many old-school engineers use when sizing up a new acoustic instrument and selecting the best mic and placement. They have someone play the guitar in the studio while covering one ear up and using the other ear like a microphone, moving their uncovered ear around the surfaces of the guitar at a distance of about 18 inches. As you do this, you’ll hear the overall tone and frequency response of the guitar vary quite a bit. Move closer in and farther back to find the spot that offers a good combination of warmth and richness in the lower range, while maintaining some of the sparkle and shimmer that your freshly strung acoustic guitar has. When you find this “sweet spot” note the distance from the guitar body and then get your mic placed as close to that sweet spot as possible.
One final, but very important consideration is to ask yourself just what kind of an acoustic guitar sound will work best on the recording you envision. For instance, a demo featuring a solo voice and guitar would need a full-bodied sound to create a solid base for the vocalist, whereas a dense and heavily produced pop track may only have sonic space for a thinner, jangly-sounding acoustic that provides a little texture amongst the many other instruments making up that recording’s sonic landscape.
In the Studio
Engineer Jeff Crawford started our test session with the “one-eared listen.” I was playing Jeff’s Takamine FS360 dreadnought guitar while Jeff evaluated its sound and decided which spots he wanted to mic. We had decided to use two of the most common mics found in any musician’s gig bag, the ubiquitous Shure SM-57 and SM-58, which would probably not be the first choice if you were recording in a top professional studio (most pro studios record acoustics with more expensive condenser mics), but because almost every musician has one or both of the Shure workhorses, it seemed sensible to see just how good a sound we could achieve with them.
Jeff started out with the SM-57, known primarily as the go-to mic for snare, toms, guitar and bass amp micing. He placed the mic over the sound hole; about 4 inches away and we proceeded to record a rhythm guitar part. The sound was full and present, but had a very noticeable increase in the lower frequency range, due to what’s known as the proximity effect, which every dynamic mic has to a greater or lesser degree. The proximity effect boosts sensitivity to bass frequencies more and more the closer the sound source gets to the mic capsule.
Local engineer Philip Johnson joined us to provide a third set of ears to evaluate the various mic positions, and after listening back, we all agreed this placement provided too much low end. Next, Jeff moved the mic back about 12 inches from the sound hole. Playing the same part, we got an evenly balanced sound that had plenty of bass, but now had the guitar’s silky mid- and upper-frequencies in equal measure. “It’s pretty much what the guitar itself sounds like in the studio,” said Jeff.
We then placed the mic behind the bridge and about four inches from the soundboard, an area known as the lower bout, favoring the treble strings just a bit. This spot provided only the mid- and upper-midrange frequencies, with a noticeable absence of the higher overtones and missing this guitar’s rich lower range.
Finally, we put the 57 up near the spot where the neck and body joined, about 6 inches away and angled slightly toward the guitar body. As expected, we got a much brighter sound that emphasized the upper mid-range of the instrument, but we also picked up a slight boominess from the body. With a little low end EQ cut, this spot might be suitable for that rock track that already has plenty of other instruments in the low end, and that would benefit from a crisp-sounding acoustic filling in between the backbeat.
Next, we switched to the SM-58, a mic designed for live vocals, but occasionally used on other instruments. For some musicians just getting started with home recording, the 58 may be the only mic they own. Compared to the frequency response of the SM-57, the SM-58 doesn’t have quite as much boost in the upper mid-range, since its primary use is as a stage vocal mic.
We decided to use the exact same placements as we had with the 57, and found out that due to the mic’s differing frequency characteristics, the contrasts were noticeable. Starting out just 4 inches in front of the sound hole, we got a sound that was bland and without much character. It was dominated by the guitar’s low end, once again due to the proximity effect. However, there was even less of the mids and highs than with the 57 due to the 58’s built-in windscreen, and its different response curve.
Moving out to the 12 inch spot, we got a more even tonal response, but it was a little dull sounding compared to the 57. Our third test spot, on the lower bout, favoring the guitar’s treble strings, surprised us as it was a pretty complete guitar sound, not as bright as the 57, but definitely usable. Finally, we moved up to approximately 6 inches away from the neck-body joint and found that in this spot, the 58 delivered a pretty good image of the Takamine, but due to the closeness to the neck, we were hearing a lot of string fingering mechanics. The tonal balance was OK, so moving the mic a foot or so away would likely retain the tonal quality but minimize the mechanical sounds to a degree. For a quick solution on the SM-58 the lower bout offered the best bet, followed by some variation in distance and placement on the neck-body joint.
One other option you may test is to try recording using a combination of the mic and your guitar’s internal pickup if it has one. Many acoustics come with a built-in pickup to help with amplification in live settings, and these pickups, depending on their sensitivity, can sometimes enhance a guitar recording. Your internal pickup will usually give its best response when all the tone controls are set flat and the volume is set full on. Pickups tend to deliver a bright sound, so if you’ll also use a mic, you might want to try experimenting with the lower bout position mic and then mix the two sounds sources to get a proper blend between low and high frequencies.
After our test recordings, we got together in the control room to A/B the results of all four positions for each mic. All three of us agreed that for the 57, a foot away and directly in front of the sound hole delivered a clean, rich tone that would be perfect in almost any home recording. For the 58, we got the best results up at the neck-body joint, again, about a foot away. Remember to take the time to test out various positions with your particular guitar, because each instrument will have a slightly different “sweet spot.”
As we started packing up, the conversation came back to studio condenser microphones and Jeff offered a few suggestions to consider when the time is right for you to add a higher-quality recording microphone to your home studio, so long as you have the necessary phantom power.
“I’ve had very good results with the A-T 4041 on many acoustic instruments. It’s a small diaphragm cardioid condenser mic that can be used for acoustic instruments and also works very well for drum overheads. It’s really crisp and tracks recorded with it cut through the mix nicely. Another reasonably priced condenser mic is the Studio Projects C-1. It has a large diaphragm, so it’s a bit warmer sounding than the 4010, which is very nice on most vocals and also good for acoustic guitar, and piano.It will work nicely with any instrument where you are looking for a crisp sound with accurate low end.” (The street price on the 4041 is $299, while the C-1 can be found for $199, including a shock mount.)
Shure SM series mics
To read the complete interview with Grammy-winning engineer Richard Dodd, get your copy of The Golden Moment: Recording Secrets of the Pros published by Backbeat Books.