I have a subwoofer from the long defunct Adire audio. I bought if from them new and it is called the Rava. It is a sealed 18" square box with a 250 watt plate amp and their Shiva driver. Still works just fine, though I toy with the idea upgrading its capabilities just for fun. my velodyne SMS gives it quite a bit of boost in the 20hz range. Anyone have any ideas on adding a more powerful amp to it for more extension down low. Or should I scrap both amp and driver and use the box for something more interesting. Any ideas would be appreciated.