subwoofer woes

Ok so I have a pair of 10" solobaric l7's (dual 2 ohm coils) in my own custom sealed box wired at a 2 ohm load to a zx750.1 amp and it hits pretty good for my first system so my buddy wanted to put a system in his truck so he decides to run the same amp but buy some kicker cvr 10's which are rated for slightly less than the l7's(400rms vs. 600rms) well heres the problem I hooked it all up for him and it sounds like complete garbage!!! I was so embarrased I couldnt even look at him I even hooked his box and subs to my system and it sounded just as bad and then just for the hell of it, hooked up my l7s to his system and it sounded just fine Are the cvr's that freakin bad or did I just make one doodiety box?? my box demensions are width 49" top depth 6" bottom depth 8" height 12" internal volume: 1.58 cft with 50% polyfil sub volume range: 1.32-2.0 cft his box(I made also ) width 51" top depth 5.5" bottom depth 8" height 13" internal volume: 1.73 cft with 50% polyfil sub volume range: 1.6-6.0 cft as you can see the boxes are very close in deminsions but boy what a difference

well I just unplugged the two wires going to the amp(monoblock) and hooked it up to a battery and one sub went in and one went out but I didnt test them indavidually SP? I have them wired like this:

Check your wiring again.  One of the speakers is connected wrong.  They should both move in the same direction.

yup just checked and fixed the problem!!!! this site is bad ass! fast responses and you guys know your doodie.. thanks