Perhaps you might explain a concept that's always puzzled me: the "warm" vs. "cold" airstreams and the idea of air volume and air pressure as two, distinct and separate qualities that affect tone quality. Thanks!
I've heard this before, and I think it's a bit confusing. Here's how I responded:
Regarding the "warm" vs. "cold" air, I'm not exactly what that concept means to be honest. I don't think of things that way. But the notion of air pressure and air volume (actually I say "air support" or "air availability") is spot on. Your support — which comes from your diaphragm flexing whenever you play — never wavers. The pressure, or speed, that you blow into the instrument does vary, and it should. Imagine a violinist only playing with one bow pressure, and well, you can imagine how boring that would sound. Same goes for wind instruments; the wind is our bow.
Finally, embouchure pressure is also something I vary, but that's when I'm trying to get a certain effect with the sound. Loose embouchure is something great to put into your arsenal for Jazz or even Contemporary music. But, it's an advanced skill that I don't teach to students, because I don't want to confuse them.
So I'll say it again. Air Support is always constant. Air pressure isn't. It's the first step to expressive playing to understand the difference!