A while back I realized that rolling back the knob just a little would actually make the top end of whatever guitar I was playing actually come through more clearly.
Anyone care to explain why?
I have a theory about this, with no science at all to back it up.
A certain part of the signal that's coming off a pickup is in the very high treble range; it might manifest as air or sparkle when you listen closely to the instrument by itself but in a mix you don't really hear this. Still, the amp is working to reproduce it and it may still be affecting the overdrive character a bit (almost subliminally) with its very fast cycles. It seems to me that rolling off a bit of these highest highs could lend a bit more energy - and perceptibility - to the lower presence-range treble that we really do hear in a mix and which also colors the overdrive more audibly.
Sort of the same as when the mid scoop of an A5 mag can make the bass response in a pickup seem more prominent because the mids aren't taking power and attention away from it. I'd suspect it's perhaps 90% perception and only 10% actual difference in amp tone. Still, lower frequencies carry more sound energy and even a little extra in that mid-treble may give you significantly more "cut" in a mix than a larger relative amount of the super high highs.
Also, many of us oldtimers have lost significantly more of the high highs than we have of the presence highs; that could well enter into it. Speaking for myself, I never noticed this effect when my ears were young. Hard to say if that is a factor: not only wasn't my listening as highly developed at the time but I also didn't use my tone controls as much back then.
Anyway, I have no evidence whatsoever to support this. But I've noticed the same effect and as the saying goes I'd argue it over a beer.
On my Kramer Baretta, the volume knob says tone, so there. ~ (At least it used to, it's been a while since I've played it).
On my SG Junior, I mess with the tone knob a lot so I can fake some neck pickup tones. It works well. my dual humbucker guitars stay wide open for the most part on the tone knobs but I will mess with them if needed. I find myself doing that a little more lately.