• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Humming through stock stereo

M

mechanicboy

New member
My 2006 Monsoon stereo hums sometimes. I usually hear it very slightly at low volumes but sometimes it pretty loud. When it's loud it seems worse when out into gear and reduces in neutral. It gets bad enough that I've removed the fuse to stop it.

I had a ground issue that was causing low voltage but fixing that didn't help the stereo.

Thanks.
 


Its worse in gear than neutral because in gear there is a load on the belt system more than when the car is in neutral. I'll bet the noise is feedback noise coming from the alternator.

Do you have an after market amp or anything? When was the last time the alternator was replaced?

Im sure its a ground somewhere causing it. I had this problem once in an old 95 GTP that I had a pretty good sized audio system in running 180 amp alternator and 3 batteriers. (2 in the spare tire well and a 5500rm MA Audio amp.) If I reved the car the noise would get louder with RPM of the engine.

It may sound insane but Im pretty sure I know exactly what that sound is like. Its either a bad ground somewhere or alternator connection or harness connections on the back of the head unit in the dash.

Need to know what was done and when you first noticed this issues. What was changed whats different?

New battery? New Alt? New amp? If you have an Amp Junk RCA's that dont have very good shielding on them can cause this too. Anything?

something is causing the feedback obviously.
 
Like others have alluded to you have an issue with the ground. What ground issue did you have and what did you do to remedy it? It sounds as though you have a ground loop which is usually caused by separate grounds at different potentials usually the factory ground at the radio and the antenna ground can cause that. If you have aftermarket componets like Tyler said look into those, if the system is totally stock then look into the Antenna ground and the radio ground. Measure the resistance between them.


Jeff
 
I remember this happened on my boat once, turned out to be "non resisting" spark plugs...

Maybe something to look at? Not sure if this applies to auto plugs as well...
 


99% of the time its a ground. those plugs did nothing in the old days, wont do jack today.

body grounds are where id start looking.
 
Usually plugs will give you a crackling popping sound. Ground loops and issues will give you alternator whine.

Jeff
 
The ground issue was the chassis ground coming from the battery to were it bolts to the body. There's a disconnect link between the two and it had melted the wire/assembly. I assume it melted because the wires were messed up and only a few were still creating the ground. I cut the crappy setup that GM had there and made a direct link to the chassis.
 
You need to pull the radio out to check. The chassis ground could cause an issue, but you seemed to have that fixed. Now look at the radio.

Does this sound increase and decrease with engine RPM?

Does it get sound like a whine or is it a hiss?

When did it start, or has it been that way since you got it? Has it progressively gotten worse?

When you say that you pulled the fuse I have to assume it happens even with the radio off.

Is your stereo totally stock? If not what has been done?

Please be specific in your answers.

Jeff
 
J57ltr said:
You need to pull the radio out to check. The chassis ground could cause an issue, but you seemed to have that fixed. Now look at the radio.

Does this sound increase and decrease with engine RPM? I can't remember, I think it increased.

Does it get sound like a whine or is it a hiss? Both, but I think the whine changed with the rpm.

When did it start, or has it been that way since you got it? Has it progressively gotten worse? Always been that way, only had the car 2 months. It suddenly got worse after I was parked idling for a couple minutes in town.

When you say that you pulled the fuse I have to assume it happens even with the radio off. Yes, the sound was the same no matter the volume or even when it was off.

Is your stereo totally stock? If not what has been done? Completely stock Monsoon system. The rear speakers sound like at least one is blown, so I disconnected them. They seemed to crackled as I wiggled the connection while disconnecting them.

Please be specific in your answers.

Jeff
Click to expand...

Answers in BOLD in your quote. Maybe I'll put the fuse back in a recheck your first two questions.
 


I would confirm that. It will tell me if it is alternator whine a failure in the radio itself or a combination.

Based on your answers since it does this with the radio off, I believe this to be the amp is on for the chimes since they sound through the speakers. It is either there is a ground loop between the antenna and the ground. Test by ohming between the two. It should measure 0 to several tenths of an ohm. Try disconnecting the antenna and playing a CD or see how it responds when off.

The other 2 possiblites are defect in the amp (likely caps in the input section of the power supply) or other defect. The other option is the radio itself.

i don't know exactly how the info is passed back and forth with the interface to the car, but those are the likely things to look at.

Jeff
 
You must log in or register to reply here.
Back
Top