What would be the difference...

[Joe Nerve]

...between a 400 watt 4X10 cabinet and a 1000 watt 4X10 cab, if you were only running 200 watts into them? And which if either would be louder?

 

[T-Bird]

Hi.

The one with a greater efficiency will be louder if either one of them doesn't fart out (run out of excursion) with 200W.

Published power handling figures aren't comparable anyway.

Regards
Sam

 

[Implosion]

If everything were somehow mystically equal (speakers, efficiency, total volume of the innards cabinets, volume were the speakers start to give up, etc.) and the only difference would be power handling, then the cabinets would sound the same. But of course in real world one speaker can take 50 W and the other 250 W there are going to be differences.

edit: +1 T-Bird

 

[VisualShock]

if you run your amp into clipping, you'll risk damaging the speaker. if at all in doubt, buy an amp that can output more than your speakers can handle.

When your amp clips, it sends a nasty signal to the cone, potentiall causing it to overrun it's mechanical excursions...
if you buy a 300 watt head and a 200 watt cab, then only send 2/3s power, or something simmilar. avoid amp clipping.