Pant leg wavin. Usually just enough for moving air. Some speakers that do not like to breakup an are actually better representation of your sound when they don't.
Recording, Marshalls begin to inhale at about 4 an they start to pump air nicely at about 6-8 on master. I'm referring to an older JMP style, non master or modded master or early with master JCM style.
Peavey gain head, XXX, 5150 etc.. master/post on 4-6, pre about the same. I have a Trace mod so it sounds good at lower volumes too, to me at least.