These days with modern and affordable digital recordings available, musicians, singer and song writers have become audio recording engineers. So recording acoustic guitars are made easier at home in a bedroom. Sometimes getting a good natural acoustic guitar sound can be difficult if the acoustics of the room has deflection problems.
So the first thing they do is to select the correct microphone for its use, (good condenser microphone). For an acoustic guitar, you can apply two different techniques: a single, or mono, microphone technique, or a two-microphone, or stereo, technique. How you position the microphones into action is up to you and also it depends on what recording resources you have available at the time of recording.
For good crystal clear quality recording of acoustic instruments you must use a quality condenser microphones rather than a dynamic microphone, that’s for sure. Good condenser microphones for acoustic guitar recording include the AKG 451 or the 414 or the RODE NT1. The reason why you will require a condenser microphone rather than a dynamic microphone is very specific; Example: condenser microphones have much better high frequency reproduction and much better transient response, in which you must use for acoustic instruments. Dynamic microphones, like the Shure SM57, are great for electric guitar amplifiers which don’t need as much transient detail as such.
You must listen to the sounds of the acoustic guitar as the player is strumming it. As for the sound you will notice that the most low-end effect is near the “sound hole” itself, the higher-end effect will be somewhere in the region of the 12th fret.
Now, let’s take a closer look at the two types of microphone I mentioned earlier. If you are using just a single microphone, you will want to get going by placing the microphone in the region of the 12th fret area. If that doesn’t give you the sound you are looking for, then reposition the microphone around, after you record it, you might want to give it extra body by doubling the track, recording the same section again, and then pan it to the right and left. When using a single microphone technique, you might notice that your guitar may sound a little lifeless, (depending on the guitar used). This can be generally normal if you are going to be mixed into a mix with many other musical instruments in stereo mix, but this situation should be avoided when the acoustic guitar is the most important focus of the mix. A better sounding acoustic guitar should be used.
When two microphones are used from your collection, then position one around the 12th fret area and the second microphone around the bridge area. Full pan the two microphones to the left and right on your recording hardware or software and start your recording session. You will discover that the recording has got a much more natural and open tone, in reality it is easy to explain, everyone has two ears, so when recording using two microphones, it sounds more realistic to our brain. The other option is you can also try an X/Y configuration at around the 12th fret section, place your microphones in a way that their capsules are on top of each other at a 90 degree angle, facing the guitar. Pan left/right, and you will become more aware of the natural stereo image.
If your guitar has a built-in pickup then you might want to experiment using the built-in pickup in addition, that is if you have got the extra inputs on your recording source to do it. Occasionally using the acoustic guitars pickup and blending it with microphones can produce a more detailed guitar sound; then again, it is totally up to the recording person to experiment with it, and in many situations, unless you are using a good quality pickup, it will sound unacceptable on a studio recording system. Keep in mind to experiment with each recording session. From experience every situation will be different, and if you do not have any microphones to record with, then using a guitar pickup will do the job.
If you are mixing your acoustic guitar into a full- rock band with other guitars, especially if those guitars are in stereo, you might be better off with a single-microphone technique, because a stereo acoustic guitar might introduce too much sonic information into the mix and cause it to become untidy. If it’s just you playing guitar and recording vocals, a stereo or doubled mono technique will sound most excellent.
Using an audio compressor on an acoustic guitar can be very subjective; few recording engineers use it on recording sessions but it can depend on its guitar situation. I personally barely ever compress acoustic guitar, I prefer the natural sounds of a good acoustic guitar. If you decide to compress the acoustic guitar then try to use a gentle compression with a ratio of 2:1 or so, this should do the trick. As for me the acoustic guitar itself is very energetic musical instrument and you would not like to spoil the tone of its beautiful acoustic sound. Please keep in mind that this audio recording modus operandi can be applied to any acoustic musical instruments.