Mics - I use both a Dynamic and Condenser, after trying and buying literally over 15 recommended microphones I have narrowed it down to what works best. When I say that I mean the combination that gives me the true tone and dynamics of your amp when recorded.
For those of you with cash simply use a Royer R-121, this mic by itself will capture your amps true sound at a high volume and setup is easy. However this mic is $1300.00. For those not willing to spend that read on...
If you want to be a bit thriftier the combination I found that captures the amps true tone consists of using different microphones, the dynamic Shure SM-57, and the condenser AKG Perception 400. The Shure can be had for under $100 and the AKG can be found for around $225. However this combination recorded on two seprate tracks will play back like you are in the room.
Setup - First we will setup the Shure 57. You are going to want to turn up your mixer or preamp that the mic is plugged into to so you can easily hear the hum of the amp through the headphones. Then use the headphones to listen to the amps speaker while you move the 57 around trying to find the sweet spot. The 57 should be almost on the center cone but a bit offset and about 3 inches from the grill at a 45 degree angle. With the headphones on move around the mic until you hear the cleanest sound from the speaker. You are only hearing the hum of the amp but you will be able to tell the difference in tone, move it until you hear the hum very clear, not muddy.
Next we will setup the AKG. Turn the level all the way down or off on the 57 and bring the AKG up until you clearly hear the amps hum in your headphones. Since this is a condenser mic you will have had to of supplied it with phantom power. Move this mic to another speaker in the cab and set it back about 30 inches to start. Begin the same process as with the 57 in moving the mic around until you hear the clearest tone from your amp. Once you have it positioned turn up the gain on the 57 so that you can hear both mics together in the headphones.
Here is the first problem you will need to solve, phase. The microphones will be out of phase and the hum you hear will sound as if you engaged a phase shifter. Here is how we will correct this.
Without moving the 57 out of its final position move the AKG mic a bit forward or back until you clearly hear the phase stop, you are now in phase.
The last step will be to slightly tilt the AKG mic so that it is setting at around 30 degrees and not vertical. Once you have done this and you can clearly hear both mics without the phase sound you have the mics set for optimum performance.
Recording - Next when begin recording in your DAW set each microphone on its own track. Turn up your amp to the loudest you will have it when you record it. Next set the faders so they are equal but not bouncing up in the red or clipping. Record your tracks with your guitar.
Mixing - In your DAW pan the first track to left 50%, and then the second track right to 50%. Adjust your faders to optimum volume and you got it.
What you will find with this set up is a very clean accurate duplication of the amps tone. It really is the best I have found in the two years of figuring out how to get it perfect.
I hope this helps some of you who have not been satisfied with your recordings and mics. Below is a pic of my setup
Surf
