Miking a cab is simple: you just point a mic in its general direction, right? Yes—and to get to the moon, just jump really high. Actually, there’s much more to miking than meets the ear, as you’ll find out from these tips.
1 Dynamic Mics Rock Shure’s SM57 dynamic is the classic guitar-cabinet mic. Many engineers choose it even when cost is no object—although there are some excellent “upscale” dynamic models available.
2 Condenser Mics Roll Condenser mics— though often too sensitive for close-miking loud amps without being padded (see below)—produce a more open response. They make good “secondary” mics. For example, placing a condenser further back from the amp adds definition to a primary, close-positioned dynamic when the sound captured by both mics is blended.
3 Ribbons Rule Although ribbon mics used to be fragile, newer models are more rugged. Ribbons have a warm personality, and a polar pattern that picks up sounds from the front and back—but not the sides. In multicab guitar setups, ribbon mics let you do cool tricks by choosing which sounds to accept—and which to reject—based on mic placement.
4 Pads Matter Many mics have switchable attenuator switches (called “pads”) to lower the sound level, for example by -10dB. With loud amps, engage this to avoid distortion.
5 Placement & Tone Moving the mic closer to the speaker’s center tends to give a brighter sound, while angling the mic toward the speaker—or moving it further away—provides a tighter, warmer sound.
Start off with the mic an inch or two back from the cone, perpendicular to the speaker, and about half to two-thirds of the way towards the speaker’s edge. To capture more of the cabinet’s influence on the sound (as well as some room sound), try moving the mic a few inches further back from the speaker.
6 Try Different Speakers Each speaker in a cabinet should sound the same, but that’s not always true. Mic each speaker, and listen for any significant differences.
7 Add a Direct Sound Some amps offer direct outputs (sometimes with cabinet simulation), and combining this with the miked sound can produce a big sound. However, the miked sound will be delayed compared to the direct sound—about 1ms per foot the mic is positioned away from the speaker. Nudge the miked sound earlier in your recording program until the miked and direct sounds line up, and are in-phase.
8 Use a “Flight Simulator” Programs such as IK Multimedia’s AmpliTube 3 let you move virtual mics around in relation to a virtual amp. The results parallel what you’d hear in the “real world,” and you can learn a lot about how mic placement affects the overall sound.