Recently, I began to notice that occasionally my car's stereo would make a very quiet high pitched tone. This comes n goes, and is very random. The high pitched tone is very quiet, and barely audible when playing music at low volume to mute/paused. It doesn't whine up or down according to rpm, so I'm ruling out alternator. It sometimes goes away if I turn off the headunit and turn it back on.

Is this something ground related?

 

If you have wires run for an aftermarket amp or subwoofer there are components throughout the car that radiate a lot of electrical noise even back in the trunk. Even if you don't have an aftermarket set up some of the wiring could be picking that up. I had to move some of my wires a few inches right or left to get rid of noise in my system. If you do have an aftermarket amp, it could be that the gain is slightly too high. You could have a shop put a ground filter in your system briefly and that would let you know if it was a ground or not if it goes away.

 

I have an amp for my Sub and factory bose. I guess it must be cuz I tuned my amp recently. That would make sense. I changed the xover and gains.

Thanks! I'll see if readjusting it makes a diff.

 

On another note, since you mentioned you have factory bose...sometimes when you add an aftermarket speaker amp it gets hooked up along with the oem bose amp, so they are both running the same speakers...this in a sense, increases the overall gain of the system and creates noise. The bose amp should be taken completely out of the loop if you have a speaker amp. It seems you only have an amp for your sub though, so in that case I'd try to move the sub wires around to avoid the electrical interference. Worked for me.

 

I have a JL amp for my JL W6V2. Asides from that, my factory Bose setup is still intact. I checked my amp settings earlier and I had the gains way maxed out on my amp. I lowered it and I've not heard any more of that random high pitched sound. I'll check again in a couple days though. Thanks for your advice

 

the BLOSE setup runs at like 3 ohms, most other amps and speakers run at either 4 or 8 ohms. i would run all the other speaker off of an amp. what kind of rca cables did they run? i have noticed in the past that if you use cheap cables you will get noise. dont run a ground isolator, if there is noise, the amp isnt grounded properly...ideally it should be no longer than a foot and at least 8 gauge wire

 

back in the day when i was installing (16 years ago) when we got a car with bose we would rewire everything