Once in awhile my stereo system will go haywire and I will get this loud buzz noise from my speakers. It's so loud it hurts and I have to shut off my car for it to go away.

I have done an install with a zapco amp, an alpine 9855 HU and some speakers. Can anyone tell me what is going on? Is it grounding? Is something loose?

 

Sounds to me like one of your speakers is grounding out- it may be moving slightly and touching something due to the vibration in the car.. My system did that when one of the rears were grounding. I thought my head was going to explode from the noise.

Blew out my head unit also. It was awesome.

 

Any idea how I can find out where the problem is? It did it to me about 5x so far in the last year. It's been about 4 months since the last time but that scrares the hell out of me so I'm looking to get it resolved.

 

first thing i would try is next time the noise happens disconnect the power to the amp and if problem stops then you know its in the amp, amp wiring, or the subs. If keeps on then we know interior speakers or wiring from headunit to speakers.

(to disconnect amp power either pull fuse or screw off the ground wire for a few secs)

 

It’s very difficult to solve a problem that occurs this intermittently (2 to 4 months between occurrences in your case).

I doubt it’s a positive 12v power wire grounding, since that should result in blowing a fuse or tripping a protective breaker in one of the devices. And, it doesn’t sound like a “ground-loop” since that would happen most of the time.

I think cheshirecat79 may have the correct answer.
From your description it sounds as though a positive wire is going to ground. That could be a speaker wire coming from the amp (or an audio wire from the H/U to your amp, but this is not as likely, but certainly possible).

Re:> “Any idea how I can find out where the problem is? It did it to me about 5x so far in the last year. It's been about 4 months since the last time but that scares the hell out of me so I'm looking to get it resolved.”

I think the first thing you should check is the wiring from your amp to the door speakers. This is the most vulnerable area since the wire runs through a flex-point (opening and closing the door constantly bends and flexes the speaker leads that pass through a grommet), and closing (slamming) the door can disrupt the speaker and/or its wiring.

Do this:

• Open the doors and remove the door panels.
  
  
• Carefully trace the speaker wires from the amp to your speakers, looking for any rubbing that might have scraped the insulation allowing the positive wire to touch metal (and that could be a “double-scrape” allowing the interior wire-metal of the negative and positive wires to touch one another).
  
  
• Then look carefully at the connection to your speaker’s terminals (and the crossover if you have that). Could an exposed connection contact any metal in the door?
  
  
• Next check the speakers’ mounts. Is it stable? Can the speakers shift when someone slams the door closed? If you have spacers: Do the spacers firmly hold the speaker in place?

If that checks out, then it must be a problem with your amp. And if so, it's a wiring problem and not a defect in the amp itself.

I just hate this type of problem since it’s so difficult to solve. Keep us posted on your progress.

--Spike