Stumped!

i just put in new subs in my car and they are not hitting like they should. when i got to messing around trying to find out what was wrong, i found that when i disconect the ground and reconect it, the subs will hit hard like they are supose to, only for a few seconds then it will go back to not hitting hard again... i am wondering if my amp is not big enough for the speakers.... i got a crappy 900w jvc amp(bridged) pushing two 600 rms 1200 peak subs.. is the amp the problem

well, the JVC amp is overrated (as usual) and will not preduce enough power. Don't forget, running two 600rms subs is a total of 1200wrms and your amp will produce 900wpeak. You need a extremely large amp to run that, somewhere around 1200w rms and 2400 peak. I hope you are running 2 DVC subwoofers or else your amp will be way up there. JVC is not a good brand, i do not recommend them."I don't play games. I play Nakamichi and that for real yo" - Probably some japanese kid said this in the early 80's trying to sell stereo out of his trunk lol.

the subs are 2ohm or 4ohm dvc.... so you think i need a better amp? i have them set at 4ohm and then bridged in to the amp, is that a problem?

what subs do you have ( dvc or svc what ohms per coil) with this info we can recomend amps for you. you might try and ground to a different place and ensure it is tight to a bare metal no paint.

Thomahizo, use this link and show us how you have your subs wired.  http://www.sounddomain.com/shop/wooferwizard.pl

it is set up like option 2 https://images.cardomain.net/sites/sounddomain/shop/woofer_wizard/2_4ohm_dvc.gif my subs are T1 Rockford Fosgate 12" they are 2 or 4 ohm dvc.... hope this helps you help me

t112d4

Okay, then the amp is not being overloaded.  It's outputting at the 4 ohm bridged rating.  The problem is that it starts out loud and gets quieter, so it's not consistent.  Power  wire gauge and in-line fuse rating is what?  Ground wire is what gauge?  And be sure you are disconnecting battery neg terminal before you disconnect any wiring on the amp incl. ground.  Sounds to me more of a wiring and/or power supply issue rather than the amp being too weak for the subs.

I've had that problem once since I've been installing. Took me 8 hours to fugure out that I had a bad ground.   Try finding another, better grounding point.2004 Mazda 3s Hatchback

2- MTX 4500 8" subs powered by MTX 251D