Zen and Mic Placement

Recording Jimbo has been a trying experience thus far considering we haven't gotten anything recorded yet! He's been very picky about mic placement. He just wasn't digging the sounds we were getting -- I think it was also partly because he was a little out of practice. In any case mic placement made a good scapegoat.

So, today I took my brand new MXL 990 Large Diaphragm Cardioid Condenser -- what a mouthful -- microphone out for a spin. I ran a couple of experiments to find some real sweet spots in the sound field of the acoustic guitar. Subject to record: steel string acoustic guitar finger-pick style. Objective: find the best mic placements for acoustic guitar with the MXL 990.
MXL 990 Polar Pattern

The cardioid directional pattern of the microphone suggests that it will reject most SPL (sound pressure levels) from behind, and to the side. In essence it should only possess about 180 degrees of pickup range. Keeping this in mind, I attempted six separate microphone placements:

3" from the source placed at the 17th fret, facing the fretboard.

Aside from weak sound levels, the overall sound quality of the recording is undesirable. Facing the microphone towards the fretboard eliminates the bassy characteristics of the soundhole, but amplifies the noisy squeaks and thumps of the hand moving around the fretboard. The metallic sounds of the strings give the recording a tinny quality. Though not unpleasant, it seems to encompass too much of the guitar's sound.

3" from the source placed at the 17th fret, facing the soundhole.

This is a very desirable mic placement. The microphone is off-axis from the soundhole, so the bass is still there, but not overbearing. The wooden qualities are more prevalent in the timbre of the recording, and string noise is greatly reduced. However, the sound of the fingers picking the strings creates a knocking noise that muddles the recording somewhat. The tone is very intimate do to the close proximity of the microphone to the sound source. Very little reverberation from the guitar and the surrounding room enters the sound field.

6" from the source placed at the soundhole, facing the soundhole.

What a really awful way to record guitar! The sound of finger picking dominates the recording, with the woofy bass from the soundhole filling in the rest of the gaps. You can even hear the musician bumping into the microphone as it impedes his normal posture on the guitar! The recording sounds like listening to guitar with a pillow over your head. Granted, that is the way I prefer to listen to Jimbo when he speaks, but his guitar should be enjoyed sans pillow.

12" from the source placed at the 12th fret facing the soundhole,
3" above the soundhole.

My favorite recording of the day! This placement is all killer and no filler. Soundhole and fretboard share equal ground. String noise is present, but not annoying. The bass is punchy, but not all-encompassing. There is some air and natural reverberation captured as well. The guitar has a live quality, which gives it great character as a solo instrument.

12" from the source placed at the 12th fret facing the soundhole,
3" below the soundhole

Most of the qualities of the last placement are maintained. A little extra middle end is added to the sound field, but the finger picking noise is also pronounced. worthwhile choice for plectrum guitar style.

12" from the source placed behind the body of the guitar facing the soundhole.

Quite an interesting placement indeed. I like it because the wooden resonance of the guitar body gets its chance to shine. The levels are a tad weak. Might be a suitable choice to couple with a closeup mic at the 22nd fret.

If you opt to try a two mic setup be sure to check for phase issues. The mics might be spaced far enough away to create cancellations in certain frequency ranges. A thin, or disjunctive sound will result. Solve by reversing the phase on one of the tracks in your DAW or on your mixing console.