Before you record any tracks, put a new set of strings on your guitar. Use a high-quality set of strings! Don’t use cheap inexpensive poorly made strings. I like Elixirs, but whatever your favorite strings happen to be use them. This will give you a sound that will make your recordings sound awesome. This will make a great improvement to the overall sound quality when recording acoustic guitar. Strings have a life expectancy. Newer strings will sound better on your recordings.
Skinny strings sound brighter than thicker strings. So if you’re looking for more midrange or bass in the tone of the acoustic use a heavier gauge string.
A condenser microphone will always sound better than a dynamic microphone for acoustic guitars. A condenser microphone will also sound better than the built-in acoustic pickups. The condenser will capture higher frequencies that dynamic microphones and your acoustic pickup will miss. Popular microphones for recording acoustic guitar include AKG 414, Neumann K84, AKG C1000, AKG C3000, Neumann K184, and Sony ECM 50.
Again everything depends on the sound you are going for. So take some time to experiment and see what works. In the past, I have used one condenser. Sometimes I have used 2 condenser microphones. On occasion, I have used one condenser microphone and also plugged into the piezo pickup at the same time. I recorded two separate tracks while doing this. Then I use the volume and the pans to blend both signals together during the mix.
Microphone Placement
Here is one way I have used two condenser microphones in the past. One was placed towards the top of the guitar body and set on an angle looking down the body. It was pointed at the Soundhole. The other mic was placed on the opposite side of the soundhole. It was aimed toward the soundhole and the neck.
So as you can see there are many ways to place the microphone. There are many microphones to choose from to make your recording. That is what makes this an art form. Equalization begins from micing the instrument. That is why microphone selection and placement is so important.
Microphone placement is very important. Every acoustic guitar has something called the sweet spot. This is the spot that sounds the best and is the ideal place to put the mic. So look for it when you place your microphone. I have found that in most cases the sweet spot for an acoustic guitar is between the soundhole and the neck of the guitar with the microphone angled towards the soundhole. Move the microphone around until you find the sound you want. Get down on your knees and listen to different angles of the guitar.
Running the microphone through a hardware compressor/limiter will almost always improve the recorded guitar sound. Try using one. Use a real hardware compressor and save the software one for the mix.
Other Tips and Tricks
If your acoustic guitar player is a heavy breather the microphone will pick it up. Try making the guitar player wear a dust mask or a surgeon’s mask while playing. That will get rid of the breathing sound.
In some cases, you will hear fret noise when the fingers glide across the strings. To limit this you can use an emery board and very slightly file the rough edges off of the guitar player’s calluses. Once this is done the guitar player should wash his hands. This should limit the squeaking fret noise that occurs from playing fingerstyle guitar. Be very careful when doing this. A very light sanding is all that is needed.
Using all these tricks will give you better acoustic tracks.