Stereo Troubleshooting (noise/feedback through amp powered speakers only)

Hey man sorry you didn't have any luck with the RCA's... The fact that when you touch the tower has an affect on the sound would lead me to start checking ground wires first, then tower speaker wires. Just a thought but does your head unit allow you to turn on/off its internal amp? I have the Kenwood 700 and it allows me in the settings menu to turn the internal amp off. I have mine off so that I get less distortion at higher volumes. It is a long shot but may be worth a try since your heading out soon.

I think your on the right track with the HU but it concerns me that when yuo touch the tower it changes the sound of the speakers. This is telling me its shorted on the tower and the tower is acting a huge antenna. I would also pull the speakers off and inspect the wires where they go in the tower. Make sure it hasnt rubed into the wire insulation and is shorting or almost shorting. Normaly a short o the tower would kill that speaker ot the amp but its might be just enough to radiate noise threw the system.

I was also thinking the same thing, that maybe the tower rubbed into the wire insulation and was shorting. But when I connected my ipod through my mini pin/RCA to the amps, I couldn't replicate the noise for one, and touching the tower had no additional affect. It was crystal clear, even jumping around in the boat, shaking the tower, anything I could do to get some noise out of the system if it were a speaker wire but I couldn't. The noise is only happening when the HU is connected to the amps. Ipod connected directly to the amp --> no noise.... HU connected to the amps --> noise. I will inspect the speaker wires regardless in the morning, just so I can positively rule that out and what do I've got to lose anyways. Thanks for the help.

HAHA i just noticed your PNW area. How close are we? LOL. Anyhow yea i think your HU is prolly bad then if you got good sound with the IPOD directly connected.

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Originally Posted by mmandley

HAHA i just noticed your PNW area. How close are we? LOL. Anyhow yea i think your HU is prolly bad then if you got good sound with the IPOD directly connected.

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Thats what I'm thinking as well. I wonder if somehow because the internal ground of the HU is somehow bad, that by touching the tower I'm acting as some sort of grounding and thats why I'm introducing much more noise. What a PITA troubleshooting that was, specially with a newer HU. I'm up near Bremerton, WA, I'd say we're a good 3.5 to 4 hours away. Thanks for the help.

I have finally tracked down the problem. It was indeed my damn HU. I received my new Krypt 4200 EQ today and installed it back into the system. First I tried it by just plugging in my mini pin/RCA through the EQ to see if I had noise through the tower speakers. The speakers sounded crystal clear. Then I plugged in the RCA from the HU into the EQ and I had the noise! Same noise I've been hearing all along. Sooo, with all my frustration carrying on and a vacation coming up, I couldn't go without towers, so I ran down to car toys and picked me up a new Kenwood KMR 440U. Brought it back home, replaced the currect HU with the new one, hooked everything up, and wala! NO NOISE... So it turned out to be a bad HU. I hope no one ever has this problem, cause it was a PITA tracking down. I guess the worst part about it was in the back of my head I really really didn't want it to be the HU that I had just installed in the boat 2 months ago. I was trying to blame it on everything else, and because not everyone just has extra HUs laying around. I fortunately had my stocker, but for some reason it was reproducing the noise as well, so that must be a bad HU as well.

Hopefully this thread will be useful to others that experience noise through their external amped speakers. I'm not saying all noise is going to be the HU, but if you have similiar noise as I was experiencing, don't be afraid to blame it on the HU after checking everything else. The noise I experienced with this bad HU is while on the water, there was hissing, poping, and extreme krackling as the boat was rocked and bounced around by wakes. With the boat out of the water I was experiencing hissing, as well as being able to almost hear the HU thinking, like I've said before, CD starting to spin, changing songs on the CD, etc.

The HU is still under warranty, so I'll be sending it back for a replacement. The new RCA ($150) I was able to return. I may return this other HU I have, or keep for a spare. In all I don't believe I'm down much on $$ from troubleshooting, so all is good. I'm happy and ready for a week vacation! Anyone wanna buy a boat? LOL

I am glad you found the problem and glad you can return the RCA's. $150.... man that was one hella high quality RCA.... I just meant not the $10 ones from wallyworld. LOL! Again though I am glad you got it fixed. Have a fun trip!

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Originally Posted by 08LSV

I am glad you found the problem and glad you can return the RCA's. $150.... man that was one hella high quality RCA.... I just meant not the $10 ones from wallyworld. LOL! Again though I am glad you got it fixed. Have a fun trip!

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Thanks! Yeah I've always bought high quality RCAs, makes a difference. Thats why at first I didn't think it was the RCA's I had. Thanks for the help!

Thanks for the updates. I have been following this thread as I am suddenly also getting a high pitched whine thru my stereo. I am using all three sets of preouts, one per amp times three amps, and with the volume on the HU at 0, there is a very audible high pitched whine coming thru each zone (towers, cabins, sub) and with the stereo playing, there is an occassional loud popping sound as well. This is with the engine off. With the engine running, it's suddenly picking up alternator noise as well. Going to Car Toys today to pick up a replacement, probably going with the KDC-x395. I got 3-1/2 years out of the last unit and hope this new one will last longer.

Well I returned from my vacation and I had zero problems with my audio system, so I am a happy camper! Sounds like your having a similar issue as I was experiencing cab. Let us know if your new HU got rid of the noise. I never did do any troubleshooting with the boat in the water or with a fake-a-lake, so I'd be curious to know if that is some additional noise when the HU's outputs go bad. Kinda like the additional noise I had when touching the tower with my hand.