Hey guys, I just built my first home audio sub. It consists of an Adire Shiva in a sealed 3 cu ft box and a 360 watt amp. After I put everything together, I fired it up and decided to test it with some Matrix. To my disappointment the sub was bottoming out constantly at low frequencies, the output wasnt all that loud either. I can also hear the sub working and moving at higher excursions before reaching its limits. The box is well sealed and all this was happening with just 1/4 power of the amp! It's in a very large basement and is in the corner. What can be wrong? Any help would be greatly appreciated as I'm very frustrated at this point. Thanks..