Recording acoustic guitar tracks well is one of the most difficult tasks that anyone in music can do. Experimentation is key to achieving perfect results, however there are a few basic, engineer-tested microphone placement techniques and tips that will help you produce high-quality acoustic guitar tracks.
Close-miking Technique Close-miking is a technique in which a microphone is placed very close to an instrument or sound source - usually inches to 1 foot away. Musicians and engineers use this technique because of the focused sound close-miking provides. Recording instruments using this technique also minimizes bleed from other instruments and musicians in the room, as well as unwanted noise. This technique is commonly used by those recording at home in untreated rooms, or in situations where the room sound is unwanted or detrimental to the recording. Close-miking is generally done with dynamic microphones, as they have a very focused polar pattern and can usually take high volume levels. A commonly used close-miking technique is to place a dynamic microphone approximately 8 inches in front of the 12th fret on an acoustic guitar. Microphones like large diaphragm condensers and ribbon microphones are sometimes used in this way on quieter sources or song passages.
Distant-miking Technique Distant-miking is a technique in which a microphone is placed further away from a sound source -- often between 5 feet and any greater distance. This technique is used in situations where a combination of the sound of the room's tone and the instrument are desired, usually in recording studios with acoustically tuned rooms. Distant-miking techniques generally cannot be employed in situations where bleed is an issue, and are usually only used when an instrument is recorded overdubbed or recorded in isolation. Microphones like large diaphragm condensers and ribbon microphones with figure-eight patterns are commonly used with this technique, as they tend to pick up the most detail and natural sound.
Combination Miking Technique Combining close-miking and distant-miking techniques often yields the best result possible if done correctly. Many engineers use a dynamic microphone close to the neck or sound hole of the guitar, while placing another microphone, usually a large diaphragm condenser or a ribbon microphone, further away to capture room sound and reverberation. Using this combination technique will allow you to capture all of the details and full sound created by the guitarist and instrument -- from slight hand movements with a close microphone, to a full, warm sound with the distant microphone. Using two microphones enables you to use more of the distant microphone or the close microphone later during mixing. When using this technique, make sure to space the microphones at least three feet from each other to avoid phase problems that can result in weak signals and poor sound.