Good results on acoustic guitar can be had by those working in modest studios with minimal gear. Conversely its still possible for instruments to sound less than their best in larger facilities; here are the things to get right whatever the studio.
In Summary
Recording such a seemingly simple instrument is not without its pitfalls, and the trinity of a good instrument, well-played and well recorded holds true. Good results rely almost as much on practicalities upstream of the mic and ahead of the mix.
Going Deeper
Whether lending texture to a dense mix or playing a pivotal role in it, the acoustic guitar’s charms pervade many styles. While these can bring different variations on body size, tunings, or string material, some general principles can apply when approaching any situation.
Many will be aware of one of the familiar recording trope that references the quality of what goes in versus what comes out… The acoustic guitar in some ways personifies this, not least because of the number of variables to consider, and the fact that parts can often be highly exposed in a sparse arrangement or solo recording.
If it’s someone other than you playing the guitar you’ll be recording a bit of pre-production can help no end. If you don’t already know them then gaining a rapport with the artist is often overlooked as a factor in more successful recordings. In the absence of a chat or even some gig-recce time, even a YouTube performance can help to get a feel for the artist’s shtick (and other more practical considerations such as how animated they are when playing).
Careful With That Axe
Assuming that the player has the necessary chops to play the instrument, the next consideration is the guitar itself. Dead strings are a bit of a non-starter, especially on steel-strung instruments (the majority), so talking about this before the session with the artist can help. The guitar’s intonation is harder to address on acoustics, but their fixed bridges can also help to keep experimentation to a minimum! Assuming the instrument is of adequate quality and is in good condition then the odds of success are good…
Although it is less common to record a DI from electro-acoustic guitars, DI’ing can still be useful in the studio. This output could be used for special re-amping effects, or even used in-behind the mic, however more significant is the use of electronic or plugin tuners. Most jack outputs need batteries to drive them. If the artist has spares then all the better- distortion in the signal can be caused by low voltage meaning it’s time for a change. Some modern preamps use AA batteries that don’t make a raid on the TV remote out of the question.
Performance, Fashion, And Physiology
It’s easy to forget that acoustic guitar bodies amplify anything that is in contact with them, including any funky zips, buttons or jewellery, and headphone leads. Most artists want things to sound as great as possible and will be happy to help out with this. Some artists will stand and move a lot as part of the performance, others will sit while playing; a good solid chair without wheels that doesn’t produce mysterious squeaks or grunting noises is a must… While players will insist on breathing throughout the entire session, other mechanical noises such as fret squeaks can result (or not) from technique; its been said that talcum powder on sweaty fingertips can help.
Headphones Or Headaches?
When it comes to cue mixes less is often more, and aside from how these should be delivered, perhaps more fundamental is if these should be used at all. A solo performance with no click renders headphones unnecessary unless remote talkback or monitoring with an effect is required. On the subject of clicks, many percussive sounds are great at finding their way into acoustic guitar mics. Soft shaker-type sounds can be more forgiving; better still is to fire the click MIDI into a high piano root note. These are harder for mics to hear.
Weapons Of Choice
Engineers often reach for condenser models on acoustic with good reason; their higher output is a bonus when recording quieter parts. Large diaphragm mics generally have a higher output than smaller capsule mics; something worth considering for any delicate picked parts. Many also cite condensers’ extension at the top as compared to dynamic models, but many famous recordings have been made down the latter. Condensers’ faster sound can also help to better etch the guitar into the mix; dynamic mics’ ability to ‘blunt’ the sound can sometimes be more appropriate.
Ask ten engineers what their favourite acoustic guitar mic is and yes, you’ll often get ten different answers. If a mic or mics are available that are known to work well on acoustic, then putting those up initially is a good idea. It is, however, useful to bear in mind that some instruments can have unhelpful body bumps in their response. Maybe that chunky ribbon mic might be better holding up a thin voice instead. Any extra HF from a bright mic is easy to dial back; lack of HF is always harder to conjure.
A Placement For Everything
Any acoustic instrument sounds different as the listener moves around it, and although a usual mic position can work most of the time, we’re still surprised on those occasions when that regular default doesn’t sound good. Theory dictates that the mic should be at least one instrument’s length away; in practice the desire for an up front, detailed sound means the mic often lands much closer than this in any style other than classical recording. Positions can include in front of the instrument, above, or even to the side. Polar pattern can be exploited to reject breath noise or the vocal itself in the case of singing players.
One well-trodden technique is to listen on headphones while moving the mic around to get into the sweet spot. This relies on zero latency and a lot of level in the right headphones. Another technique is to instead record and review different test positions with a spoken ‘ident’ such as “on axis, 12th fret, 50cm”. This makes candidates far easier to decide upon.
One Mic Good, Two Mics Better?
For acoustic guitar ‘pads’ whose purpose is to add size to a busy arrangement, sometimes a simple approach works best. Mono guitar recordings can often bring the acoustic sound without treading on the toes of stereo instruments; parts can be tipped up to one side to mirror different instruments, or a pair double-tracked and panned to taste to counterbalance each other.
Where the acoustic is the main focus, or for sparser arrangements, stereo acoustic guitars can work well, however they can raise some extra considerations. The first is finding the sweet spot; if there is a preference for just one place for the mic that could rule out a spaced pair. Using a coincident technique instead can deliver width without compromising position. In very dry environments, when summed to mono spaced mics can develop phase-related ‘swishiness’ as the instrument moves relative to the mics. Coincident stereo mics have the advantage in this respect of being unaffected by players who tend to move as they play.
Adjusting width using angle and/or spacing can help make space in the middle of the mix for the vocal if spaced pairs agree in mono.
Final Thoughts
Although mixing the finished product is perhaps beyond the scope of this article, it goes that recording well is the best mix processor out there for acoustic guitar and everything else. Recording technique can either make or break the pastoral, pure beauty of the acoustic guitar; getting it right can mean a highly rewarding experience for engineers, and repeat visits from clients who prize its nuances being well rendered. What are your starting points towards acoustic guitar perfection? Let us know in the comments.
A Word About This Article
As the Experts team considered how we could better help the community we thought that some of you are time poor and don’t have the time to read a long article or a watch a long video. In 2023 we are going to be trying out articles that have the fast takeaway right at the start and then an opportunity to go deeper if you wish. Let us know if you like this idea in the comments.
Main photo by Chris Hardy on Unsplash
Guitar photo by Ahmed Rizkhaan on Unsplash
Mic photo by Jacek Dylag on Unsplash