Friend has an amp/sub/HU problem.

[nole16k 10+ year member]

Here's the deal. My friend has two 12" Kappa perfect subs with an Infinity 1211A mono amp and Pioneer head unit. His subs did not used to do this, but recently they've been making a small "humming" sound (you can fell them vibrating with your hand, as if the subs were playing a constant tone to a song) when the head unit volume is turned all the way down and the amp gain is all the way down. You can adjust the freq and other setting on the amp and the problem still persists. Does the problem lie within the subs, amp, HU, or some other component? Does anyone have any clue what the problem is? I can't give anymore details regarding the problem because I haven't tried any other tests, etc. to see what the problem could possibly be. I've simply only listened to the sound that the subs make.

Thanks

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[Raven 10+ year member]

Does it get higher / lower with engine RPM? Sounds like a poor ground to me.

 

[nole16k 10+ year member]

I'll check tomorrow and see. The ground wire is basically hooked onto a bolt that was already screwed into his car, because this was the easiest place to put it when we were installing his system (we had to transfer it from his old sedan to his new SUV). It's on the bolt of one of those hook things in a trunk of an SUV that you can use to tie stuff down with or hook something up to.

 

[btmorris972 10+ year member]

sand all the paint from under that bolt. also make sure your using adequite (SP?) ga ground and power wire.

if possible hook his subs up to your amp to rule out the possibility of damaged subs. do the same with the amp.

good luck

 

[nole16k 10+ year member]

Thanks for the replies guys. He's using 4 ga. ground and power wire, because this is the largest size the amp will support. I'll do some trial-and-error tests tomorrow.

 

[nole16k 10+ year member]

We found out that the problem is engine noise. It only happens when the car is turned on and it increases when the RPMs increase. Does an alternator noise filter work or will we have to use another remedy? We removed most of the paint from the bolt and the plate that the ground wire attached to, but that obviouly didn't help much.

 

[btmorris972 10+ year member]

its got to be your rcas or ground. are your rcas running right beside the power???

 

[nole16k 10+ year member]

Yes, the RCAs are running right beside the power wire, but they also do in my truck and I have the exact same installtion kit w/same RCAs. If you upgrade to some high-quality RCAs, can this greatly reduce or eliminate the interference, or do you have to run the power wire on the other side of the car?