Need Help
Registered User
Joined: Aug 2002
Posts: 425
From: DFW, TX
Originally posted by LWillmann
Couldn't the head unit's pre-amp output be screwed up?
Couldn't the head unit's pre-amp output be screwed up?
Originally posted by LWillmann
He could try a a high to low level converter. That would eliminate the pre-amp output.
He could try a a high to low level converter. That would eliminate the pre-amp output.
Thread Starter
Registered User
Joined: Jun 2001
Posts: 83
From: Naperville, IL
Well I tried running new RCA's from the HU to the amp and the same problem happened. My friend that lent me the extra set of RCA's also has a new Kenwood deck that he said I can try to hook up to see if my HU is messed up so I'm gonna probably try that later tonight once he gets off work.
Till then, he said that I should just attatch a CD player via the RCA's and he said the amp should still take that sound and make it hit.
*I also wanna say thanks to LWillmann, RallyRedTexan, and anyone who has helped in this thread, I'm happy I can get this kind of help. I just hope that we can solve this odd problem.
Till then, he said that I should just attatch a CD player via the RCA's and he said the amp should still take that sound and make it hit.
*I also wanna say thanks to LWillmann, RallyRedTexan, and anyone who has helped in this thread, I'm happy I can get this kind of help. I just hope that we can solve this odd problem.
Thread Starter
Registered User
Joined: Jun 2001
Posts: 83
From: Naperville, IL
Just tried the CD player trick where you take a CD player and plug it into the RCA's. And it still hits the same way 
! I don't know of anything anymore that is causing this that I haven't already tested.
! I don't know of anything anymore that is causing this that I haven't already tested.
Registered User
Joined: Aug 2002
Posts: 425
From: DFW, TX
Maybe your car just doesn't want a new stereo, you know cars have feelings too 
. Sorry this thing hasn't worked out. You need to go see a professional and have them look at it. We've tryed everything imaginable here 
. Good luck and make sure to revive this thread once you get it fixed.
. Sorry this thing hasn't worked out. You need to go see a professional and have them look at it. We've tryed everything imaginable here . Good luck and make sure to revive this thread once you get it fixed.
Registered User
Joined: Apr 2000
Posts: 450
From: Winnipeg, MB, Canada
First thing I would do is verify you're getting a decent signal for the HU. Do this by turning the HU up and testing the voltage output at the end of the RCAs that plug into the amp with a DMM (one lead to the center pin, the other to the barrel. test both R and L channels), what does it read? You should get AT LEAST 2v when it's turned up but even 1v would be sufficient.
What gauge wire are you using for power? what gauge ground? How long is the ground wire? did you scratch the paint away when you attched your ground wire to the car? Where did you ground to? Is the amp turning on? Do you have the sub wired correctly? both VCs positives to the amps positive outputs and both VCs negatives to the amp's negative outputs? What kind of box is the sub in? Sealed or ported? What's the box's volume? Have you checked for air leaks? You have been adjusting the gain right? What is the crossover set at?
If the amp is turning on then turn the system up and measure the output fro mthe amp's speaker terminals using a DMM set to volts, AC. What does it read?
What gauge wire are you using for power? what gauge ground? How long is the ground wire? did you scratch the paint away when you attched your ground wire to the car? Where did you ground to? Is the amp turning on? Do you have the sub wired correctly? both VCs positives to the amps positive outputs and both VCs negatives to the amp's negative outputs? What kind of box is the sub in? Sealed or ported? What's the box's volume? Have you checked for air leaks? You have been adjusting the gain right? What is the crossover set at?
If the amp is turning on then turn the system up and measure the output fro mthe amp's speaker terminals using a DMM set to volts, AC. What does it read?
Last edited by x7x7; Apr 4, 2003 at 04:24 PM.
Thread Starter
Registered User
Joined: Jun 2001
Posts: 83
From: Naperville, IL
What gauge wire are you using for power?
- 4ga
what gauge ground?
- 4ga
How long is the ground wire?
- 3ft
did you scratch the paint away when you attched your ground wire to the car?
- Yes
Where did you ground to?
- Directly to the car
Is the amp turning on?
- Yes
Do you have the sub wired correctly?
- Yes
both VCs positives to the amps positive outputs and both VCs negatives to the amp's negative outputs?
- Yes
What kind of box is the sub in? Sealed or ported?
- Sealed
What's the box's volume?
- .6 cu ft
Have you checked for air leaks?
- Their are a few small ones. But once I know it works for sure they will be sealed.
You have been adjusting the gain right? What is the crossover set at?
- Yes, even changed it though all ranges to see how it hits.
- 4ga
what gauge ground?
- 4ga
How long is the ground wire?
- 3ft
did you scratch the paint away when you attched your ground wire to the car?
- Yes
Where did you ground to?
- Directly to the car
Is the amp turning on?
- Yes
Do you have the sub wired correctly?
- Yes
both VCs positives to the amps positive outputs and both VCs negatives to the amp's negative outputs?
- Yes
What kind of box is the sub in? Sealed or ported?
- Sealed
What's the box's volume?
- .6 cu ft
Have you checked for air leaks?
- Their are a few small ones. But once I know it works for sure they will be sealed.
You have been adjusting the gain right? What is the crossover set at?
- Yes, even changed it though all ranges to see how it hits.
Registered User
Joined: Aug 2002
Posts: 425
From: DFW, TX
x7x7: Thanks for helpin' out but I think we've managed to help him exhaust all possible options as far as self diagnostic. I'm willing to bet if I had a look at it, it'd be fixed in an hour. Only problem is, he needs someone local. Good luck Ice.
Thread Starter
Registered User
Joined: Jun 2001
Posts: 83
From: Naperville, IL
RallyRedTexan - Wanna take a trip to IL? heh.
Today we tried my friends new rockford amp and the sub ended up hitting pretty hard... but didn't sound as clear as I would like it to be. I also took the sub and amp out and took it to 2 car audio places and they both looked at the sub and they said it seems fine. The guy at circuit city said he has the same exact setup and recently he had the same problem with his amp. He called MTX and they told him to send it back that they had this problem with a few units. The other person at tweeter said its either the HU or the amp.
Now what puzzles me is that even though it hit about 2 times harder on my friends amp... how come the sound quality seemed to suck and it was a "hard" bass rather then a more "smooth flow" bass that I had installed in other cars? I also had max bass setting on the HU to hit the way it did with the new amp.
Today we tried my friends new rockford amp and the sub ended up hitting pretty hard... but didn't sound as clear as I would like it to be. I also took the sub and amp out and took it to 2 car audio places and they both looked at the sub and they said it seems fine. The guy at circuit city said he has the same exact setup and recently he had the same problem with his amp. He called MTX and they told him to send it back that they had this problem with a few units. The other person at tweeter said its either the HU or the amp.
Now what puzzles me is that even though it hit about 2 times harder on my friends amp... how come the sound quality seemed to suck and it was a "hard" bass rather then a more "smooth flow" bass that I had installed in other cars? I also had max bass setting on the HU to hit the way it did with the new amp.
Registered User
Joined: Apr 2000
Posts: 450
From: Winnipeg, MB, Canada
1. You'd be surprised how much what seems to be a small air leak can do to output for a sealed enclosure. Fix the leaks now and see if that cures the problem.
2. Did you do the tests with the DMM? You need to use a DMM to properly troubleshoot most problems. If the do both of the tests I mentioned above you'll be able to narrow down the problem to one specific component. If voltage at the RCAs is none or little there is a problem with the RCAs or HU. If it's normal then the problem is further up the path. If the AC voltage out of the speaker terminals tests low then you know the amp isn't generating much power so it's either set wrong or has a problem. If it's up there then you know it's a problem with the sub or box (probably box).
Sounds to me like your enclosure not being properly sealed is causing most of the problems but if you test the speaker outputs on the amp you'll be able to tell for sure.
BTW, the crossover should be set to about 80Hz.
2. Did you do the tests with the DMM? You need to use a DMM to properly troubleshoot most problems. If the do both of the tests I mentioned above you'll be able to narrow down the problem to one specific component. If voltage at the RCAs is none or little there is a problem with the RCAs or HU. If it's normal then the problem is further up the path. If the AC voltage out of the speaker terminals tests low then you know the amp isn't generating much power so it's either set wrong or has a problem. If it's up there then you know it's a problem with the sub or box (probably box).
Sounds to me like your enclosure not being properly sealed is causing most of the problems but if you test the speaker outputs on the amp you'll be able to tell for sure.
BTW, the crossover should be set to about 80Hz.
Registered User
Joined: Apr 2000
Posts: 450
From: Winnipeg, MB, Canada
Originally posted by RallyRedTexan
x7x7: Thanks for helpin' out but I think we've managed to help him exhaust all possible options as far as self diagnostic. I'm willing to bet if I had a look at it, it'd be fixed in an hour. Only problem is, he needs someone local. Good luck Ice.
x7x7: Thanks for helpin' out but I think we've managed to help him exhaust all possible options as far as self diagnostic. I'm willing to bet if I had a look at it, it'd be fixed in an hour. Only problem is, he needs someone local. Good luck Ice.
Registered User
Joined: Aug 2002
Posts: 425
From: DFW, TX
Originally posted by x7x7
He hasn't even broken out a DMM, there are many more diagnostic test that can be done to determine the problem. Unless you can test things and see values you don't actually know where the problem is and what is going on.
He hasn't even broken out a DMM, there are many more diagnostic test that can be done to determine the problem. Unless you can test things and see values you don't actually know where the problem is and what is going on.
. Sorry bout that.
Registered User
Joined: Aug 2002
Posts: 425
From: DFW, TX
Originally posted by Mad_Ice
Now what puzzles me is that even though it hit about 2 times harder on my friends amp... how come the sound quality seemed to suck and it was a "hard" bass rather then a more "smooth flow" bass that I had installed in other cars? I also had max bass setting on the HU to hit the way it did with the new amp.
Now what puzzles me is that even though it hit about 2 times harder on my friends amp... how come the sound quality seemed to suck and it was a "hard" bass rather then a more "smooth flow" bass that I had installed in other cars? I also had max bass setting on the HU to hit the way it did with the new amp.
Thread Starter
Registered User
Joined: Jun 2001
Posts: 83
From: Naperville, IL
It works! 
I tested everything and everything seemed fine so I kept getting pissed off. But then after taking everything out I re-attached it for a final time and me being the safe one left the power wire and fuse attched while hooking it back up.... well I got a big shock from the power wire on the amp, but here's the great thing... It caused the amp to work!
With the clear sound coming out of the speakers and a good amount of bass, it sounds perfect. I can't thank you guys enough for all the help thoughout this weird week.
I tested everything and everything seemed fine so I kept getting pissed off. But then after taking everything out I re-attached it for a final time and me being the safe one left the power wire and fuse attched while hooking it back up.... well I got a big shock from the power wire on the amp, but here's the great thing... It caused the amp to work!
With the clear sound coming out of the speakers and a good amount of bass, it sounds perfect. I can't thank you guys enough for all the help thoughout this weird week.
