Congrats on your subwoofer purchase @stevepa if you would, just go to the back of the box and get the woofer box measurements, we'll get very close on the cubic footage. I'd hate to see you buy the wrong woofer. Overall, I don't like over stuffing a box, (unless your box is too large) it actually raises QTC by limiting air flow, the woofer acts as though it is in a smaller cavity. A couple of other comments that were a bit off... Porting not keeping up with a sealed driver....Porting a driver in itself is not slower than a sealed driver... If optimally ported, speed should be fine... Of course similar to a sealed box, if you seal a driver to get a qtc of say 1.1, it will get boomy on you, if you seal it for a qtc of .6, it will get lean... on a ported box, you can easily affect the curve with the port. Overall though, I would also want a sealed driver if I could find it. I prefer the rolloff and they don't go out of spec as easy over time. Lastly a quote on driver cone mass slowing down the driver... Yes, if cone has less mass, it will be faster, but that would only be if 2 drivers had identical motor structure... with different motor structures, the cone mass alone cannot determine the speed of a driver. In fact, If you had a QTS of say .4 and you lowered the mass, qts would drop and sensitivity would rise, the driver would want a smaller box.... I have learned a ton from others on this site, so I don't want to come off rude or condemning, but I do want you to see the facts.
