Tech Tip:Guitar Miking: Getting a Great Guitar Sound, Part 3
Part 3: Mic Placement Options
Mic placement is an art, and many of its practitioners are reticent to share their closely guarded trade secrets. No mic placement scheme is absolute, but there are some tried-and-true methods that make good starting points. Still, getting the final sound to work often requires careful adjustment--and always requires careful listening. The ideal position of the mics can depend on the amp, the guitar, the volume, the room, and, of course, the way the guitar part's role fits the track.
Miked from the Front
Fig. 2: Straight-on Miking
The position pictured produces the most high frequencies. Moving the mic closer increases level and low frequencies (remember proximity effect?) and reduces the cabinet's contribution to the overall sound. There is a whole group of guitarists and engineers who claim that there's nothing worth recording from the exact center of a speaker. While this may be true of some speakers, you should test this position and judge for yourself.
If you want fewer highs and more warmth, move the mic sideways, parallel to the floor, toward the outside of the speaker. You should move in one-inch increments with someone you trust listening in the control room. With a mic inches from the speaker cone, small increments make a big difference.
Fig. 3 shows an SM57 at a slight angle on a Fender brown-face Deluxe. Usually, this position offers ample highs and more tonality than the straight-on position. Try it from both sides of the speaker, and from the top or bottom. If the mic ends up on the floor pointed at the speaker and sounds good, nail it down! The floor can trap bass frequencies and enhance tone, especially if it is wooden and built on a raised foundation.
Fig. 3: Angled Miking
If the floor seems to "close down" the sound, try tilting the amp back. Fenders have chrome legs on the sides of the cabinets for that purpose and VOX amplifiers, like the AC30 and Super Beatle models, came with tilting carriage stands that completely isolated the amplifier from the floor. If possible, I like to set the amp on a folding chair in the studio.
Figure 4 shows an MD421U on a vintage Fender Tweed Deluxe. I've tilted the amp back so that the bottom of the cabinet couples less with the floor. All of these amps are open-backed; walls (or open spaces) directly behind them greatly affect bass response.
Fig. 4: Tilted-back Miking
Front and Back
Fig. 5: Front and Back Miking
In the Middle