sub box build

im looking to build a box for my truck to fit 2 12s.i want to try to build a ported downfire box for my silverado ext cab. if i make it ported, does it matter about the airspace anymore. or should i build 2 seperate ported downfire boxes. any help or box blue prints/plans greatly apriciated

Not sure what you mean by "airspace."  Do you mean the volume inside the enclosure?  If so, it is a critical part of a ported system, much more important than in a sealed system.Support the12volt.com

Yea I meant the volume. I have 2 12" q Power deluxes. They run at 1500 watts max a peice(I think around 800 watts rms each) and a 1000 watt mono block comp amp. So should I build 2 desperate boxes or 1 box

You can do it either way, whatever you like.  But the size of the enclosure is critical for proper tuning.  What's the model number of your "q-power deluxe" subwoofers?Support the12volt.com

this is the only thing i can find bout my subs http://qpowerinc.com/DELUXEQP12.html

Wow, those things look like they will require a pretty huge enclosure... let me run some numbers.Support the12volt.com

lol there big. and hit pretty hard to.

Yea, a super peaky sub that will bottom out very easily with that kind of power thrown at them, and they require over 300 liters per driver to get anywhere near flat frequency response.  What's the largest size enclosure you can make fit in your vehicle and I'll tell you how to port it.Support the12volt.com

well here a little rough copy of a full downfire with my trucks dimensions. Hope this helps

OK, so that's about a 2.6 cuft enclosure, or about 73.6 liters.  Deduct about 10% for the volume of the woofers and the necessary braces, and you end up with a relatively small 67 liter enclosure.  Put both drivers in it, port it for tuning at 21.7Hz (2" diameter port that is 5" long) and you'll end up with a peaky system but it's the best you can do with those woofers.  You'll also have port noise but I don't think that will matter.  Also, with 800 watts being thrown at the woofers you will bottom them out around 80Hz, so be careful with the volume control and if you hear them making mechanical noises, turn it down.Support the12volt.com