toning down a mic - adding cap

[Guitarist]

After listening to last gig's recording, I realize the eBay specials that I cab-mounted have too many highs. I'm considering adding a cap across pins 2 and 3 to slope out highs above 5K or so. It's an electric guitar cab.
Any suggestions for a value before I jump in? Maybe changing the mic placement would help

[eschertron]

Changing the mic position away from the high-frequency dispersion units will definitely help. Try that first.

[The Dude]

The closer the mic is to the center, the more highs you will have (maximum phase cancellation). The closer to the edge, the more bass. Experiment with mic position first. Different strokes for different folks and I'm not saying my way is right, but I never mic a speaker dead center.

Edit: Speaking of phase cancellation. You have 2 speakers and 2 mics- stereo rig? Make sure the mics (and everything else for that matter) are in phase with each other and that something isn't miswired. 2 of the same signals out of phase would definitely be a low end killer.

[eschertron]

I'm not sure what your recording chain is, but if you are multi-tracking then you can also add the room EQ and reverb back in, artificially, after the fact. If you are mixing straight to master, then the close-mic'ing will sound somewhat unnatural regardless of how you capture the sound, lacking ambience.

[Chuck H]

I'm no spert on the matter, but... Most of what I've read about some better recordings, when it's mentioned, implicates edge mic placement as at least part of the formula. In my own experience I have usually recorded with 1x12 cabs or combos. So I never have two speakers to work with. Mic placement is NEVER centered. Usually I'm one to two inches from edge and either perpendicular to the grill or angled a little toward the center. And usually there's another mic somewhere in the room for ambient. Blending them later for best results.