I was drooling at the Tumult subwoofer. I would try ether a sealed or Passive Radiator design. The box would be 2 to three cubic feet. I would also look at an external amp such as qsc rmx1450. Just a thought

Tom

M80's VP150 QS8's Earthquake SuperNova MKV-15
Integra DTR-7.4 Outlaw 755 Outlaw M200's Outlaw ICBM