have you tried it in the car? ive seen people build sub boxes for their car in the house and not try it in the car because it sounds"loud"or "good" in the house and it sounds like crappola in the car.who built box? what kind of sub is it?, what model? the box, it's ported, so what frequency is it tuned to? how big are your ports? (diameter and depth) how big are the chambers inside the box? now send me the information on the sub ( ohms, single or dual voice coils and their ohms,max power, continuous power"rms", 'q' rating,what amp are you using?is it bridged mono, or designed that way? does it have a built in crossover, and i dont care if your head unit has one are you using subwoofer outputs or rear speaker outputs on stereo? pm me if you have to, ill skype you and walk you through everything,just call.
THEGR81
oh, and i was in trhe middle of something when i started typing, now its days later, but ill fix all yur stereo woes bra!
and oh, 3 ga. wire from under hood fusebox, drilled hole in firewall with proper size grommet (thats important, unless hijacking space elsewhere) with 60amp fuse 1' from source. ran through center console with remote and power wires sound, RCA, and future video went through kickpanel and doorjamb, under rear seat to amp 1600w rms.