Finally put the "big" box in my little car. It's 3.25cft tuned to 28hz. The sub is a TC Sounds proto-type driver. Very stiff cone, soft suspension, 3" coil, motor would best be described as a cross between the TC9 and a 3HP but with 9.25" magnet slugs. I have it on a Sundown 1500d @ 2ohms. Would guess 600w with the gain settings currently. This thing needs very little power to get loud. Sub will reach 22hz with-out unloading and has great pitch and note distinction. Not a one note groan monster.