If the volume goes down, we can proceed… keep flipping the phase until the volume goes down when they are at their zeros.
Now pick up a bat, knife or gun. Whatever you are best with. Threaten anyone in the control room with it and say, “DO NOT touch that guitar! I am going to have headphones on at extreme gain levels and am risking it all so you can have a good guitar sound.” Wave the weapon around menacingly until you are sure that they get the point. Kick them out and lock the door if you can’t trust em… now is not the time for gags.
Go out to the amp with headphones on. You will hear a hiss or buzz or hum… make sure the hum in the phones is louder than the one you can hear directly from the amp.
Do not cough; you will blow your eardrums right into each other. Be careful of any noise that may be present.
Now, extremely carefully, move Mic#2 back and forth, left and right. Slowly. You should hear a whoosh sound, much like a flanger pedal would make.
The trick here is to find the spot where the least amount noise is coming out of the headphones. Keep moving the mic until you find it.
Have you caught the theory yet? We are looking for the spot where the two mics are the most in phase with each other. If one is phase flipped, then at the most in phase spot, they will nearly cancel each other out. Find that spot! Once you get it, take off the phones and go back to the console.
Turn both mic preamp gains all the way down. Put fader one at the unity position on your console. Play your guitar and turn up the mic pre gain until you hit zero. Now mute Mic#1. Now turn fader two to the unity position. Bring up mic pre #2 until you hit zero.
Unflip the phase on Mic#2 at this point so that both mics are in phase.
Unmute Mic#1 and mess with the faders. Those two faders now become the best EQ money can buy! Turn up one, then the other, experiment to your heart’s content. Once you get a sound you like, buss them together and send em to a track… or keep them separate if you want some choices later.
Revel in your glorious new tone!