Just installed an AVIC-F700BT and a JL 300/4 amp. I get a really annoying whistle sound that almost seems like it's coming from the head unit only when I accelerate. The amp is old and a little suspect. Think that's it? Or is it most likely the deck? I am getting the low ohm light on the amp despite the fact that all of my speakers are 4 ohm.

 

Sounds like it is alternator noise. Check your power, ground and RCA cables. The RCAs should not be near the power and you must have a good ground.

 

I get a little bit of the same noise. Nothing to stress out about. You can also try some ground loop isolators. Should help a bit.

 

would you hear alternator noise from a bad ground outside of the vehicle? among the many noises i'm troubleshooting on my BRAND NEW X, one is a very very high pitched noise. super annoying and only happens when the car is turned on. i recently installed a boost gauge and had a hard time with the ground wire under the dash. hoping the noise is this and not an exhaust leak.

 

run your RCAs down the DRIVERS side of the car. The line from the alternator to the + battery post runs down the passenger side. If you don't do this you can get inductive interference. Basically you'll want to keep your RCAs away from heavy-gauge wire. You also must have a great ground too. Easiest thing to do is if your amp(s) are in the trunk then just run your ground right to the - battery post. if that doesn't fix it then your amp is getting bad. this isn't a normal thing, but it is a common issue i see quite often at my work with DIY-ers.

 

Hooked up a brand new amp and same annoying sound. Ground is to the battery. My RCA's probably are running near the power wires, but wouldn't that cause interference when listening? Sound quality is great. It's just the whistle when nothing is playing. I can try moving the amp under the seat, but don't want to go to the trouble if it is most likely not going to help. My installer didn't think this was the problem.

What about this ground isolator loop? Could that help?

 

You probably have noise when the music is on, but maybe it is too faint to hear? I had this problem on an old Honda and the installer just kept telling me to turn the volume down. This was not acceptable to me. I ended up re-running the RCA and power cables to keep them separate and it solved the problem. As for the Ground Loop Isolator, here is a link:

http://www.amazon.com/Xitel-GLI1-X1-.../dp/B00023XDYA

I do not have any experience with these.

 

Turns out my installer did run them down the passenger side. Rerouted them down the center console cause I didn't want to pull the deck. It's better, but still there. Thinking about trying the ground loop isolator next.

 

I had this same issue in my MR.

We isolated it to Turbo noise, not alternator noise. I know for a fact my amp was good. We ran shielded RCAs back to the amp, didn't fix it. We ran RCAs outside, didn't fix it. Ran ground loop isolators, didn't fix it. So then we got a stethoscope out, sure enough it was turbo noise and it was NOT coming out of the speakers. Make sure it's coming out of the speakers before you spend a lot of time trying to track it down like I did.

 

?

So the noise was coming from your engine bay?

And there was nothing you could do to fix it?

 

That is correct. I thought it was coming fro the speakers. A stethoscope told me I was wrong. Was just the turbo spooling up. I may be talking about a completely different sound, but I went through everything before I found where the source sound was.

Does yours sound very electrical?

 

you're probably right on the amp being suspect. make sure you're using proper gauge wiring + connections.. theres a incorrect voltage difference somewhere which is probably caused by a bad ground

 

Yea. Pretty sure it's not my spool.

 

you probably have a crossed wire.

~Sean

 

i swapped out the factory radio with a pioneer z120bt and now once in awhile i get a whining type noise through the speakers with i believe is alternator noise. noise gets louder as rpms increase. funny thing is that the noise isnt always there..... stock amp, sub, speakers.... rf system ss package