Condenser microphones are the go-to mics for recording acoustic guitar, not just because they have a wide frequency response that can easily capture an acoustic’s frequency range but because they excel at highly detailed recordings.
Typically, a guitar’s rich, sonorous bass starts at about 100Hz, while the shimmering highs peak at around 10KHz, which is well within the scope of most mics. The challenge is capturing enough high-end detail, in particular high-frequency transients, which are the short bursts of sonic energy heard when a note is first sounded (in this case plucked or hammered).
Fortunately, all condenser mics have highly sensitive active capsules, so they’re more than up to the job. The trick is whether to go large or small.
Condenser mics come in two flavours: large diaphragm and small diaphragm. Large diaphragm microphones are a favourite with vocalists because they flatter the voice with a touch of warmth, particularly the low end. They sound ‘big’, lush and complex – absolutely gorgeous!
Unsurprisingly, to house a sizable diaphragm, which is often about an inch across, large diaphragm mics are usually quite big lumps and, more often than not, side-address (ie its primary axis is pointing out from its side). As you can probably imagine, they’re fantastic for capturing and subtly warming up the rich bass of an acoustic guitar.
Small diaphragm condenser mics, on the other hand, are simply superb at capturing a neutral, very highly detailed account of any sound source, including the acoustic guitar. Their transient response is off the charts, and because they’re small, and usually end-address, they are easy to position with accuracy. This pointability is a quality that’s absolutely vital when recording an acoustic guitar, something we’ll touch on later.
Our advice is to invest in a good small diaphragm condenser mic if you’re planning to record your guitar using a single-mic mono set-up. If you have the budget, and don’t mind the additional complexity that a multi-mic set-up requires, then consider a large condenser for your second mic.