You can record the electric guitar in many ways:
- With a mic in front of the guitar amp
- With a direct box
- Both miked and direct
- Through a signal processor or stomp box
Use whatever sounds right for the particular song you’re recording. Mike the amp when you want a rough, raw sound with tube distortion and speaker coloration. Rock ‘n’ roll or heavy metal usually sounds best with a miked amp. If you record through a direct box, the sound is clean and clear, with crisp highs and deep lows. That might work for quiet jazz or R&B.
First, try to kill any hum you hear from the guitar amp. Turn up the guitar’s volume and treble controls so that the guitar signal overrides hum and noise picked up by the guitar cable. Ask the guitarist to move around, or rotate, to find a spot in the room where hum disappears. To remove buzzes between guitar notes, try a noise gate, or ask the player to keep his or her hands on the strings.
A common mic for the guitar amp is a cardioid dynamic type with a “presence peak” in its frequency response (a boost around 5kHz). A typical example is the Shure SM57. The cardioid pattern reduces leakage (off-mic sounds from other instruments). The dynamic type handles loud sounds without distorting, and the presence peak adds “bite.” Of course, you can use any mic that sounds good to you. Ribbon mics often work well, too.
As a starting point, try miking the amp about an inch from the grille near a speaker cone, slightly off-center—where the cone meets the dome. Close miking sounds more bassy; distant miking sounds thinner. Miking near the dome center sounds brighter; miking near the edge sounds more mellow. For a live, ambient sound, you might want to mix in a room mic several feet away.
To record direct, either use a direct box between the guitar and your mixer, or plug the guitar into an instrument input in an audio interface. Set the DI’s ground-lift switch to the position where you monitor the least hum.
It’s a good idea to record the guitar direct on its own track even if you mike the amp. Later during mixdown, you can run the DI track through a guitar-amp simulator plug-in, which might sound better than the real guitar amp did.
If you want to record the guitarist’s effects, connect the output of the effects boxes into the direct-box input. Many players have a rack of signal processors that creates their unique sound, and they just give you their direct feed. Be open to their suggestions, and be diplomatic about changing the sound. If they are studio players, they often have a better handle on effects than you might as the engineer.