Subwoofer thump+whine

[doobycareful]

I just put in a subwoofer and amp and when I turn the radio on the subwoofer makes a series of thumps like really loud then it stops but it can still be heard, very low though. Also when I turn the amp Level or Bass up or HU volume up little louder it starts thumping out of control and it only stops if I turn the ignition key off. I tried putting a ground wire from the head unit to a bolt near the shifter but it didn't do anything, tried changing the ground for the amp (but didnt sand the paint off) still nothing. Do I have to sand the paint off dose that make a difference? Or what can I do? Also the ground is curently on the back seat where it bolts down and I got the rem. wire and rca's running in the same spot but I dont think that should make a problem. Please help??????????????????

 

[just2asian]

the thump is basically the amp kicking on and letting power flow from the amp to the subs when your radio kicks on. Some amps have like something called a "quiet startup" which lets the amp turn on without the thump, cheaper and lower end amps tend not to have that option. Also make sure none of your speaker wires are touching positive to neg inside and outside the box. The best place to start is check all your connections, even if it means that you have to pull the subs outta the box.

 

[daren_p]

I was going to say turn on thump as well, but he said it makes a series of thumps & then continues to be heard, though very low. That doesn't sound like turn on thump as it usually only happens once. If you haven't already ground the head unit directly to the chassis. Make sure the amp has a good ground as well & yes the metal should be bare in both cases to make the best possible contact. As for the rca's, what other wires do you have running along side them? (I hope not power?) The rca's should be run on one side f the car, with the power on the other.

 

[doobycareful]

No other wire is near the rca's just the remote wire. They are going down the middle under the center consle.
I'm gonna go check the speaker and reposition the gound and hu wire and see if that dose anything. Thanks guy's

 

[doobycareful]

The wires inside the speaker box are ok. I've noticed that if I unplug the rca's at the amp then there is no thump. Dose that mean anything?

 

[just2asian]

you may be getting some feedback from the RCAs, are they decent rca's? or just generic ones? I used to have a feedback issue with a set of RCAs and i found out that when I was installing them I had sliced the wire open and it was grounding itself out just slighty enough to make a hum. I would get a good set of RCAs and you problem may go away, RCAs are cheap, get a nice shielded set with a thicker covering. its worth a try i think at least.

 

[daren_p]

The wires inside the speaker box are ok. I've noticed that if I unplug the rca's at the amp then there is no thump. Dose that mean anything?

Ya it means the rca's are probably the source of the problem. What kind of rca's are they? I have found that spending abit extra on a good set or rca's is defently worth it. Make sure the have a good shield & I've found "twisted" pairs tend to work alot better for noise rejection.

 

[doobycareful]

Problem solved. I was reading some threads about whining noise and a guy (I don't remember who) said that he grounded the rca ground to the HU's ground and the whining noise went away. So I sanded down a good ground and grounded the HU. Nothing. So I tried the thing that the guy said about grounding the rca's ground to the car and I put a piece of wire in there and ALL THE NOISE IS GONE. That was easy.
Oh I got some rca wires from mejier the cheaper ones but they work fine now. Thanks alot for the help I appreciate it alot.

 

[1990talon]

I have the same problem I don't get it how do I fix it?

Thanks,
Brandon

 

[doobycareful]

Well I got it from some other thread, so pretty much all I did was I took a piece of speaker wire and at the back of the HU where you plug youre rca's in put it on the rca and push down on it make sure that its only touching the outside circle of the rca's. Do this to both of the rca outlets and the let the piece of wire touch youre HU case/ground then turn on the radio and see if the sound is gone, it should be if its the same problem as mine.
Remember I did this so you don't have to if you don't want. I'm not responsible for any damage. Do at your own risk. Hope that clears it up.

 

[1990talon]

Well I got it from some other thread, so pretty much all I did was I took a piece of speaker wire and at the back of the HU where you plug youre rca's in put it on the rca and push down on it make sure that its only touching the outside circle of the rca's. Do this to both of the rca outlets and the let the piece of wire touch youre HU case/ground then turn on the radio and see if the sound is gone, it should be if its the same problem as mine.
Remember I did this so you don't have to if you don't want. I'm not responsible for any damage. Do at your own risk. Hope that clears it up.

Thanks I am not going to mess with it till next week B/C my car broke down . Got to fix it first