Distorted electric guitar can be an unruly monster to keep under control sometimes, but I am finding that less is more when it comes to getting a good starting point for guitar amp mic placement.
If you are using a multi-speaker cabinet, the first thing to do is to find the best-sounding speaker of the bunch. Take two Shure SM 57s and point the first one directly at where the dust cap meets the speaker cone; and point the second one at the speaker cone (not to the centre of the speaker!) at a 45 degree angle from the first. The mics should be touching each other to ensure minimal phase difference. Now what you have is one mic that is picking up the brighter tone (straight on mic) and one that is picking up a darker tone (45 degree angled mic) of what the speaker puts out. This enables you to select either a warmer or edgier tone simply by changing the fader level relationship between mics, instead of having to immediately jump to the EQ. Always use a flashlight to see through the grille cloth to ensure proper placement; add more mics if desired end result requires it and stir well!
Brad Nelson is a Metalworks staff engineer who is co-producing and recording the new Headstones album for MCA and has recorded and/or mixed for acts such as Treble Charger, Spooky Rubin, the Killjoys and Tribal Stomp.