Lets say I have a commercially available Definitive Technology sub, which sounds terrible because of the noise the air generates out of the port. Would stuffing the port or closing it give me better sound? How can I evaluate the quality of the bass? Should I use an SPL meter, or bassy music? Or, given the fact that I have the amp and a 10 inch cone in it, do you think I'd get better results by using this stuff and doing a DIY cabinet? If so, how should I proceed? I obviously don't know the operating parameters of it.