“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.” -Brubart
Before Miking Up
The best way to start with an R-121 is to spend some time listening to the amp you’re recording. While playing your guitar (or better yet, have someone play it for you), listen to the speaker cabinet and the individual speakers, both close-up (watch your ears!) and from different places in the room. At a close distance, you’ll find that the speakers are brightest at the center of the dome, then they become darker as you move off center towards the edge of the speaker. You’ll also find that the sound changes as you back away from the cabinet, often developing increased tonal complexity and low end, with the cabinet developing more thump and the acoustic characteristics of the room coming more into play.
Miking Electric Guitars
The following positions are good starting places for miking guitar cabs with R-121’s. Try these positions to familiarize yourself with the microphone and how it picks up your amp. These positions are good for the R-121, R-122 and R-122V, but we’ll refer only to the R-121 for this writing. Like everything, once you have the basics, experiment to see what else you find!
For the brightest sound, position the R-121 6″ to 8″ from the grill cloth, with the ribbon element centered on the dome of the speaker. This is usually too bright sounding a position, but it’s good to know this sound before moving on. Like a tone control, you’ll find that wherever you place the mic, moving it closer to the center of the speaker will give you more highs.
The tone becomes warmer as you move the microphone from the center of the speaker towards the edge of the speaker. Keeping the mic 6″ to 8″ from the grill cloth, move the mic halfway between the dome and the outside edge of the speaker. Point the mic straight ahead at the speaker cone. After listening to that, leave the mic in the same place but rotate it in its stand so it is pointed directly at the dome (center) of the speaker. The difference may be subtle, but you’ll definitely hear it.
Now move the mic back to a distance of two feet, then three feet. This working distance is far more useful than many people know. You get speaker and cabinet development, and the spaciousness can sound remarkably good. The sound of the room you’re recording in will affect your results – a good sounding room can add a nice character to your guitar tracks. If the room doesn’t sound great but you like the ambiance of distance miking, you can hang sound deadening material behind the mic (no closer than 6 inches to the mic) to minimize room sound.
Now try the same positions you tried in #1 and #2 above, but closer to the cabinet (3″ to 5″ from the grill cloth). Being closer to the speaker, you’ll notice more of a direct sound with very little room ambiance. You’ll also notice the bass building up as you move the mic closer to the cabinet. This is due to proximity effect, which is a bass buildup that occurs as the microphone is moved closer to the sound source – the closer the mic is to the sound source, the greater the degree of bass buildup will be. Some microphones exhibit greater proximity effect than others – ribbons tend to have a lot of it. Proximity effect can be very useful, as when a vocalist moves closer to a studio condenser microphone to give a bigger, more authoritative sound to their voice. The same thing happens when using a ribbon on a guitar cabinet – the sound gets heavier in the bass as you move the mic closer to the cab, even by only an inch or two. You can balance the bass and bring more highs in by moving the mic closer to the center of the speaker.
For a dramatic bass buildup, place the mic 1 to 2 inches from the grill cloth. The microphone’s proximity effect will give you larger-than-life low end. If the sound becomes overly bass heavy and overpowers the highs, simply back the mic off a little and/or move it closer to the dome of the speaker.
Note: When recording electric guitar at extremely close working distances, we recommend tilting the R-121 forward by 15 degrees or more. This angling of the mic helps to protect the ribbon element in extremely high SPL usage.
For tracking aggressive electric guitars, many engineers like to blend a close-up R-121 with other mics that have a more pronounced high end response (57’s and 421’s work well). Record the two (or more) mics to separate tracks and blend them to taste during the mix. The close-up R-121 will give big bass and strong mids, but the proximity effect may dampen the highs (depending on how close to the center of the speaker the mic is placed). Blending in the more aggressive high end response of the other mics gives a well-balanced rock tone.
Another option is to place an SM-57 close up and an R-121 three feet back pointed toward the middle of the cabinet.
http://www.royerlabs.com “Recording Tips”