I have a Premier 3004SPL DVC 1000RMS 3000Max watt 12'' subwoofer in my truck. It is located between my bucket seats in a custome ported box. Because of the space issue the port ended up being fairly close to the corner of the face of the box. And fairly close to the sub. The Box is 14''x21'' ( face ) and 14'' High. The sub is firing upwards. I have been thinking hard and long about building a new box, but I would like to try and tune this one to see if i can get around doing so. The port i have in it now is 3''x6.5'' recommened by pioneer. I don't know what to do because everyone likes different Frequency's so I am not sure what to go with. Plus I don;t know if I should maybe go with a slotted port or a traingle corner port. Another thing I've noticed is that my stereo doesn't sound loud, when your beside the truck, but it can be heard easily from inside a house at over 300 feet. I want it to sound loud close up also. Does this change with frequency and tuning?. Anyways. I am powering the sub with a Phoenix Gold 800Watt class D monoblock Amplifier. If anyone can answer at least some of my questions that'd be great. Sorry for such a long post. Thanks for your help