I don't think I get it
So for the Pros 10*400+90= 4090
What about this (Copied From
Crutchfield.com)
The chart below illustrates that a few dB in sensitivity can make a big difference:
Speaker...........Sensitivity Rating.........Power Needed To produce a given volume
Speaker A........ 85 dB.......................... 100 watts
Speaker B ........88 dB............................50 watts
Speaker C.........91 dB............................ 25 watts
A speaker with a sensitivity rating that's 3 dB higher than another speaker's
only needs half as much power to deliver the same amount of sound.