i have a modest sound system. 4 speakers total and a CD player/head unit. No amplifiers. Was working fine, now all speakers have this terrible sound coming out of them that sounds like a mix of static and cracking. Its not a stereo ground wire. Some web research said it might be either the battery, starter, or alternator.

Anyone have any experience with anything similar?

In my experience the alternator tends to be a whining sound that matches the RPM of the engine (i.e. the more you rev the engine the higher or faster the whine sounds).  This is caused by a ground loop and you have to find a better ground or buy a noise filter.  A crackling/static sound could be several things...

• Check speaker connections, if it's all speakers I'm not sure that this would be the issue.
• If you have a manual volume knob the internals could be dirty, though this would normally only cause the static sound when adjusting the volume
• Is this only when listening to the radio or any source?  If only radio I'd suspect something with the antenna or it's connection.
• If it is only when listening to a CD then I'd suspect something with the read head.
• It could be something with the head unit so it may be worth further troubleshooting on that as well.

These are a few things that come to mind immediately.

 

here is what i have done. Replaced alternator for this and another reason. Didnt fix issue. I bought new wiring harness, re-hooked ALL wiring and checking all connections. Replaced head unit with new, identical model. Music is still crackling periodically whether its a CD or radio. btw, its all the speakers not just say 1 or 2.

Check the common wires on all your speakers going back to the head unit.

Do you have the problem when the key is in the accessory position?

6 hours ago, SteveJ said:

Do you have the problem when the key is in the accessory position?

I do

Then the car is not the problem. It's either a component (stereo or speaker) or wiring issue. 

2 hours ago, SteveJ said:

Then the car is not the problem. It's either a component (stereo or speaker) or wiring issue. 

thanks. I have re-wired everything except the battery power wire. will do that today or tomorrow and give an update.

Is it possible that 1 loose speaker wire (or if wire polarity is backwards) would affect all 4 speakers sound?

9 minutes ago, Wally said:

thanks. I have re-wired everything except the battery power wire. will do that today or tomorrow and give an update.

Is it possible that 1 loose speaker wire (or if wire polarity is backwards) would affect all 4 speakers sound?

nope