From my experience in the studio recording big loud 4×12 type amps do not always garner the huge tones you are looking for. Depending on the situation, having a really loud amp in the studio will create problems with bleed, headphone mixes. I wonder if you have had this problem? “I can’t hear myself” says the drummer, “all I can hear is myself” says the guitar player. Huh. Normally these types of amps need to be ran at a reasonable volume to get the speakers and tubes to work at a nominal level. Enter the small amp!
From a recording engineer standpoint, the microphone techniques are the same, and the volume issues are less apparent, (bleed, headphone mixes etc). Normally when setting up to record a guitar amp, I will usually mic the speaker with 2 microphones, a Shure SM57 and a Sennheiser 421. Or atleast 2 dynamic microphones. Dynamic mic’s like the above can handle louder SPL’s (Sound pressure level). Both mic’s are 4 to 6 inches away, although I’ve been known to move them even further back to allow the speaker to breath a bit. One mic is on axis – directly infront on the speaker and one is slightly off axis. When I mix, sometimes I will just use one or the other as the track, although where the real magic can happen is when you blend both of them together, using a bit more of one rather than the other. The tonal differences between the mics act like a tone control. Want it to cut a bit more? use more of the 421. Want more meat? use a bit more of the 57.
Recording a small amp, because of the lower volume, you can also use a condenser mic, which I would never attempt on a really loud amp. Condenser mic’s are extremely sensitive, and pick up a wider range of frequencies and a flatter range of frequencies. What this means is that you will get a fuller signal. Depending on the situation I will sometimes put smaller amps on a chair or use a amp stand just to make it easier to hear and mic. If you are recording “live off the floor” with a band, try baffling the amp a bit, so there is less direct signal bleeding into other microphones in the room. Another little technique you can try when recording is to use a room mic or a mic farther away from the amp. Normally I will pick a condenser for this. For a lead track this lets you add a bit of space into the mix without applying artificial reverb. Also its extremely handy when using talkback to be able to hear the guitarist thru a mic that’s not right in front of a speaker.
I remember reading that Silverchair’s first record “frogstomp” was recorded using only a Marshall battery amp. Whether or not this is true, I am unsure. Go back and have a listen to “Israel’s Son” and tell me that’s not thick sounding!
Almost every amp manufacturer these days are making smaller practice amps, or boutique amps. The cool thing about a lot of these amps are that they are tube amplifiers. Having a low wattage tube amp is great because you can get the same tones as you would out of a larger overdriven amp without all the extra volume. Got a favorite speaker cabinet? run an out off your amp and try mic-ing that. In my band for live playing, one guitarist uses a Marshall Tube amp, 15 watt thru a 2×12 speaker, the other uses a fender champ XD thru a 15 inch speaker cab. Super loud for live if we need it, and all the tube tone without having to carry large stacks.
Little amps play extremely nicely with effects pedals, and a lot of them have built in modelling and effects as well. check out some of the Blackstar, Peavey, Line 6 models to hear what I’m talking about.