Stumped!
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=46467
Printed Date: May 05, 2024 at 6:48 PM
Topic: Stumped!
Posted By: THOMAHIZO
Subject: Stumped!
Date Posted: December 31, 2004 at 8:26 AM
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
Replies:
Posted By: uthinkuknoaudio
Date Posted: December 31, 2004 at 9:12 AM
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.
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"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.
Posted By: THOMAHIZO
Date Posted: December 31, 2004 at 9:34 AM
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?
Posted By: wheelerdr
Date Posted: December 31, 2004 at 9:34 AM
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.
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Posted By: stevdart
Date Posted: December 31, 2004 at 9:47 AM
Thomahizo, use this link and show us how you have your subs wired. https://www.sounddomain.com/shop/wooferwizard.pl
Posted By: THOMAHIZO
Date Posted: December 31, 2004 at 9:59 AM
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 
Posted By: stevdart
Date Posted: December 31, 2004 at 10:11 AM
You keep saying they are 2 or 4 ohm DVC. They are not both. You are going by the general info on this sub model. YOUR subs are EITHER DVC 2 ohm or DVC 4 ohm. The link you posted indicates that they are DVC 4 ohm. RF page link is here https://www.rockfordfosgate.com/products/subwoofer_index.asp Find out which model your subs are so we'll know if you're overloading the amp.
Posted By: THOMAHIZO
Date Posted: December 31, 2004 at 10:15 AM
t112d4
Posted By: stevdart
Date Posted: December 31, 2004 at 10:34 AM
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.
Posted By: maaudio1
Date Posted: December 31, 2004 at 10:45 AM
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
Posted By: THOMAHIZO
Date Posted: January 02, 2005 at 7:28 AM
i just got done finding a new ground for it... and when i hook up the ground (i left the music running) it sounded good for a sec or two and it went back to bearly playing.. i am running 8 guage wire for the ground... i dont have a clue what is wrong with my system..
Posted By: gumbi_12
Date Posted: January 02, 2005 at 9:12 AM
Im kinda of new but I definantly know that, that wasnt wise to disconnect the ground while the amp was on and the car was on
Posted By: THOMAHIZO
Date Posted: January 02, 2005 at 9:39 AM
i have another question that might answer my problem... instead of running the rca cables i had to splice into the rear speaker wires and run wires up to the high input on the amp..the wires i ran from the rear speaker are the same size as the stock wires..do i need to put in bigger guage wires??
Posted By: stevdart
Date Posted: January 02, 2005 at 9:46 AM
The high level input on the amp is not working with the deck. It happens a lot, which is why I will always recommend using a high quality adjustable aftermarket line output converter instead of the amp's built-in converter. And for your own safety and the health of your gear......like I said earlier in this thread and again was noted above, disconnect battery negative wire before removing ANY wiring. Go through the steps. Shortcuts lead to disasters.
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