The bass response of most ribbon microphones on guitar cabinets is much better than that of dynamic microphones. Traditional ribbon microphones will be damaged if you position them too close to an extremely loud guitar cabinet, but our R-series mics were designed to take high SPL's and can handle close miking duties on a loud cabinet. Cabinets develop more bass resonance as you move away from them, so an R-121 one, two, three, even six feet back can give you the bass response you're looking for. Ribbons have a strong proximity effect, so placing a ribbon mic any closer than 4 inches from the cabinet grill cloth will result in a bass-heavy sound. While that's probably too thick a sound for a guitar track, it can be a useful effect. Some engineers put an R-121 close on a cabinet for exaggerated bottom end, then blend it with an SM-57 for the aggressive top end of that mic. This can give you a huge rock tone. R-121's and R-122's record bass guitar well, but if the bass is loud, best results will be achieved with the mic placed at least two feet from the cabinet. Miking a loud bass guitar cabinet closer than 6" is not advisable, as the low frequencies at high volume can exceed the mic's handling capability of 135 dB SPL possibly damaging the ribbon. Do not close mic electric guitars with our SF-series microphones, as the ribbon elements in SF mics are finer and can be damaged by excessive SPL's. They work well at a distance, however.