Why does the sub sound like sh*t?

Hey, I dont know much about car audio, but I have an Audiobahn 10" 1000 Watts RMS & an audiobahn 1000 Watt RMS amp.  I just droped them into the trunk of my Prelude but they sound like sh*t.  I hooked the amp up to a REAL sh*tTY 12" Crankinstien that a buddy had & it POUNDED real loud... sounded alright to.  But the audiobahn hardly makes a noise... I thought that maybe the box was to big.  It's about 4 feet wide, 1.5 feet deep & 1.5 high. HELP ME!!!!

This is a set up of a single DVC sub..... did you wire it up like this ?

As well, did you fabricate the box for the sub or was it a premadebox for another sub ?

The box is just 6 slabs of wood sealed together in a rectangular shape.  I couldn't buy a premade box as the sub is to deep to fit in any boxes I could find.  I was reading up on the Audiobahn website & it says thier that the more power your putting into the sub the smaller the box should be, is this true?

Also, it is wired properly, i wired it incorrectly at first & it didnt make any sound, the amp kept going into protection mode so I wired it correctly.  Hoever, it still doesnt make as much noise as it should.  I've heard one of these before & it sounded great, this doesn't.  Could the quality of the wiring from the amp tot he sub be such a large factor, or is it the box?

depending on how its wired.  If its wired like in the post above in the picture the resistance/ohm value could be the problem.  A dual 4ohm sub wired like in the picture would read 8ohms to the amp and wouldn’t get half the power that your “friends” sub was getting.  It could also be wired up so the amp sees a 2ohm load.  Not sure if the amp you have is stable running at 2ohms bridged.  Look in your specs sheet that you got with your amp.  Might want to take a volt ohm meter and check out your resistance of the subs the way you have it wired up.