Last Saturday, I tried my hand at profiling a miked amp, a Vox AC15CH through an AC30 2x12 extension cab from North Coast Music with Eminence GB12/V12 speakers miked with a Sennheiser e609. (Hey, it's what I have lying around the house. 
) I had kind of mixed results, and it left me with a couple questions about the profiling process.
Before I get started with my experiences with the AC15, I did want to ask about one statement in the profiling guide that I found curious:
However, there are a few exceptions: some distortion pedals use a special design that cannot be profiled accurately, for instance the Tube ScreamerTM.
What exactly is this "special design"? I mean, the Tube Screamer is common as dirt and has a huge number of knockoffs and derivatives, so it doesn't seem all that "special" to me. Is it the input buffer on the TS that's the problem? If not, what is it? And if that's the case, why do I see so many profiles that claim to have a TS or similar boosting the reference amp?
Anyway, first I did direct and studio profiles of the Top Boost side of my AC15 set slightly crunchy, which turned out great. I created a merged profile from the two, and that worked great as well. So far, so good. Then I set up the Normal side of the AC15 "Brian May style" (dimed with a treble booster, a BBE Bohemian, out front). The direct profile of that worked OK. Then I tried making a studio profile... and that's when things went off the rails.
First, the profiler complained that there was a noise gate on in the signal chain. Now, there was a noise gate in the signal chain, an EHX Silencer (the recent version) which had the Bohemian in its loop, but it was off. Maybe "off" on the Silencer isn't really off, but I didn't try to rewire things because I had a larger issue (see below). But could the Kemper really be complaining about the fact that there's a noise gate present in the signal chain even if it's off?
Second (and more problematic) was that the resulting profile sounded nothing like the real thing. The profile was MUCH bassier and less midrange-y than the real thing. So I tried combining the direct profile of the Normal channel with the cab from the Top Boost profile, and got more or less the same result. That leads me to think that the huge bass in the cab is almost certainly an artifact of the mike, probably from proximity effect. (I had the e609 about 1-1.5" off the grill cloth.) How do people generally handle mic proximity effect in cab profiles? Run the mic through a mixer or mic preamp with a low cut filter? Mike the amp from further away? Tweak it with the Low Shift cab parameter?
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