I've always understood headroom to mean more amp power than cab power. But then ...... Lets say I'm pushing a 350 watt amp into a 700 watt cab, and am playing a small club, and only need to turn the amp up to 5 - I still can get more volume if I need, but I don't need it. Isnt this headroom? Or I have an amp thats bridged to 1200 watts into the same 700 watt cab, same club (or even bigger) and I only need the volume on 3. I still have room to go, although more. But arent both of these examples "headroom?" So is headroom just an arbitrary term that means "you can still get louder if you need to"?