There has been much written in different magazines about how to record the acoustic guitar well. There are some very good articles out there that are worth reading, and my aim here is not really to add anything new, but to give a bit of an outline on what I have found to work for me when recording and mixing acoustic guitars, so that the DIY recordists out there among you might find some useful tips that you can use to help improve the sound of your recordings, or at least give you some food for thought, and maybe some different ideas to try out. So here we go!
It goes without saying really, but without wanting to just state the obvious, it is important to have a nice sounding guitar with good strings on to start with. If it is a cheap and nasty guitar, or has dull dead strings on it, you will never acheive a good sound no matter what you do. If it don't sound good in the room, it ain't gonna sound good on the record. Personally, I prefer to record with a guitar that has strings on that have had between 1/2 hour and 5-6 hours playing time. Brand new strings can be hard to keep in tune, and strings much older than 6 hours start sounding a bit dull, though sometimes that may be the sound you are after.
My favourite technique for capturing the guitar involves the use of two microphones placed about 30-40 cm from the guitar and recorded to two seperate tracks. Usually I place a large diaphram condenser mic (Rode NTK, NT1, Neumann U87, etc.) aimed at the position where the fretboard meets the body, and a small diaphram condenser mic (Rode NT3, Shure SM81, etc.) aimed at an area between the bridge and the sound hole. Different mics have different characteristics so it's hard to really generalise here, but mostly the neck mic will be a little bassier, and the bridge mic a little stringier, if you know what I mean. The two mics blended together should provide a really nice "average" picture of the guitar sound with a fullness from low to high that is just not there if you use only one microphone. However, it is important to keep both the mics the same distance from the guitar to keep them in phase. As an added precaution against phase problems, if your preamps/mixer have invert switches try different combinations of in/out till you find the one that sounds the best. Try to keep the guitarist the same distance and angle from the mics throughout the performance to keep the recording consistent.
If you do decide to go for the "one-mic-infront-of-the-sound hole" method, be prepared to have to roll off a fair bit of low end, as the response there is usually pretty bassy. Personally I always like to record with a little compression on both mics, not hard, but maybe a ratio of between 2-4:1 with a moderate threshold. Acoustic guitars can have some quite vicious transients, and the closer you are to the mics the more likely they are to cause problems, so you might want to consider using a limiter at the end of the chain to catch the unexpected peaks.
Just as an aside, try to get the performer to play with the headphones up "not too loud", because unless they seal very well you can get leakage from other instruments getting onto the recording, particularly if a click track is being used, and there is nothing more frustrating than finding later on that you can't get rid of an annoying tambourine, snare hit, or whatever.
Mostly I prefer not to use line sounds from a guitar's onboard pickup when recording, but sometimes it can work quite well for a slightly more electric/acoustic sound when used in combination with one or more mics. This might be helpful, for instance, if you record the same guitar several times over, and don't want every track to sound the same. Maybe use two mics on one gutar part, and a mic/line combination on the second guitar part. Once again, watch out for phase problems, and you might also find a slight time alignment discrepancy between the mic and the line recordings. Slightly move one of the parts in relation to the other until you find the fullest sounding combination.
As for rooms to record in, I think there are really two options. Find a nice live room (maybe a bathroom) without horrible short echoes that cloud the sound, but that still has a brightness about it, or use a pretty dead room that has no echo problems. After all you can add reverb and delay effects later, but you can't get rid of horrible early reflection sounds off a recording. Try clapping your hands in the room and listening to the amount of echo.
So hopefully you will now end up with a nice recording .So what now? In the next article we will look at sitting the guitar in the final mix, touching on equalizing, positioning in the stereo field, and the use of effects. See you then.
Tony Koretz is a musician, singer, songwriter and audio engineer, based in New Zealand. He is involved in all aspects of music production, from writing and playing music to recording, mixing and mastering.
He runs Rocksure Soundz Ltd, a recording and production company.