The model 31 has those dual 8" woofers, and the bass response is no where near the output of the single 15". They sound great at lower volumes, but for a working situation, I'd have to discourage the use of the 31's. They just don't have the ooomph.
If it's home or studio use - OK, but for larger situations, clubs, weddings, etc ..... I wouldn't recommend it.
Didn't mean to spoil your day, Mike .... just passing along some "on the job" experience for the other readers.