Does this look familiar???Now this box is 48" wide and 36" long and even at the angle the baffle is at there's maybe an inch on each side with the 15" woofer (baffles are 18"+)This box has a significantly louder output around 80hz than I desired especially for such a large driver. It seems that the lower frequencies start losing control sooner than expected...seeing how the cavity of the vehicle (minivan) is flexing during this issue I definitely need to invest in a few layers of sound deadening material. Perhaps the electrical system to the amp is to blame for the lack of control at low frequencies as I am concerned about the voltage drop during the issue. But at the same time it might be as simple as reducing the sealed portion of the box? The woofers are Power Acoustik p3-15 powered by a 5500watt Class D amp. Personally, I don't care for what power outputs amps say they have. I simply go by the fuses and type of amp it is. In this case it's a Class D and has 5 40 amp fuses. Since Class D amps are at least 90% efficient that means at most 180amps can be sucked in by the amp at a given time...which is over 2100watts...Of course my voltage drops down to around 9volts at high volume and my amp can run at 1ohm and it's currently setup to 2ohm so obviously I am not even close to 2100 watts. If I had to guess I would say closer to 700 watts or so given the limitations of my electrical system and woofer impedance. This is with 4g wire(cheap) and a 4farad cap. To make my estimate all the more confirmed I am using a 140amp fuse at the battery for this setup without issues...although who knows what the fuse can actually handle. I am thinking I need to upgrade to 2g wire with a ground block and keep the voltage at least up to 11v...maybe I'll achieve 1000w then?for you newbies in the car audio...or any kind of audio field 1000w is a lot of juice...not walmart 1000w but serious truely rated watts. One would be surprised what an 80watt 8inch sub in a properly proportional amp/box can do make you want to throw away those 1200watt mtx terminator 12s you paid $150 for. do your homework...ask questions...time is money..the more time you invest in reviewing the more money you save. Do it right once or do it twice wrong....your choice.