well as some of you might know...... i recently ordered a Nady XA900 amp and a Dayton 15" DVC. I have had the sub for a couple days and it has been patiently waiting for the amp to arrive. the amp got here today and it looks great. strong construction, good packaging, and the fans are quite compared to some ive heard. well i hooked it up and turned it on at very low level. and immediatly i notice a strange noise. it sounded like it was coming from the sub. so i turned it up just a hair and bent over right in front of the speaker. there seemed to be a strange crackling and poping noise that sounds like it is coming from directly behind the dust cap of the driver. this is at pretty moderate levels with only a few mm of movement. it progressivly gets worse as the volume goes up. i removed the speaker and im in the process of returning it to parts express. should i have any problem getting my money back? i dont feel i should since it was clearly defective. i also just ordered a Tempest from www.acoustic-visions.com so here is my updated situation. I have a enclosure that is 5.25 cubic feet and tuned to 21hz with around 44sq/in of port area. I have a Nady XA900 amp that is rated to produce 675wrms x 1 @ 4ohms. What kind of performance can I expect from the Tempest in this setup? thanks alot to everyone who has helped me so far!!