Manufacturers should measure cabinets with a SPL meter across fequencies, from 1w up through burnout. Better them than the consumer.
You'd see that after so much power goes in the bass just doesn't get any louder.
At least they should do MAX SPL and power needed to reach MAX SPL.
And of course include polar charts for dispersion.
+1 on this. You're absolutely right, but amp manufacturers would not do this because of that whole sales thing - the fine art of smoke, mirrors, and BS. Pay no attention to the mouse behind the curtain. NARF!
