GM Bose System High-Frequency Noise!

I recently purchased a new 2005 GMC Envoy XUV with the Bose Premium Sound AM/FM/CD/Cassette option. (It also has the rear-passenger radio & climate controls.) The problem I am experiencing is a very high-frequency noise emanating from the rear speakers - but ONLY when the engine is running. The noise does NOT vary by engine speed. But it is constant regardless of the source and regardless of the volume level. It is difficult for some people to hear but becomes obvious once the engine is shut off (and thus becomes noise-free). My dealer has replaced every radio component in the car (head unit, wires, connectors, amps, speakers), installed filters and noise suppressors, re-routed the wires - just about everything you can think! But nothing has worked. For now I am forced to either "deal with it," leave it off, or turn off the rear speakers by activating the back-seat headphones. I'm not too happy, as you can imagine. At this point, I would explore employing some kind of band-pass or band-stop filter, either at line-level or speaker-level. Just anything to kill the noise! Any help would be GREATLY appreciated! Thank you. Brent

I'd stay on the dealer and make them either find a fix or get you a different vehicle... but have you checked the engine ground strap or the negative battery terminal?  In some new builds, the graound connection gets painted and that can cause noise in the audio system.Support the12volt.com

I smell lemon law. Just mention it and they will cringe.Certified Security Specialist

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Thanks for the quick reply guys. I am in the middle of a formal dispute with GM and the BBB Auto Online but the problem is that a lot of the GM technicians claim they simply don't hear the noise. So they are reluctant to replace my car unless they can confirm this with more than one dealer. (A few of the service writers at my dealership confirm it but others, including the service manager don't. A second dealer claims nobody hears it.) I'll admit it is extremely high-pitched and difficult for most people to hear but I hear it and it drives me nuts! They are sending an independent technician to investigate the problem very soon but they have made it clear that I can not interfere or influence this technician lest I have my case thrown out. I need to show them how to hear it because to the casual listener it is not obvious. And it's very directional. Just moving your head a few inches out of the sound path makes it inaudible. But I don't want to jeopardize my case. So I am thinking in the worst case scenario, if they deny me any restitution, what I can do to eliminate or at least mask the noise by employing a filter of some kind. Anyone know how I might go about such a task? Thank you again! Brent

Get access to a RTA, take it with you to the dealer, turn it on and hold the mic where you hear the noise, turn the radio on, watch the spike on the meter, tell them to fix it now or I am going to sue the living shhh out of you. The problem with high pitched noises are that some people can hear them and some people can't. It varies person to person. The RTA doesn't lie, and it can be used as proof. By the way, RTA=Real Time AnalyzerCertified Security Specialist

Always check info with a digital multimeter.

I promise to be good.

Tell Darwin I sent you.

I've been sick lately, sorry I won't be on much.

Auex, Excellent idea! Hadn't thought about that. Any thoughts on where I might obtain one? Perhaps a pro-audio or electronics repair shop? I know a great pro-audio tech (guitar amps, musical instruments). Perhaps he has equipment. I doubt Radio Shack sells anything like that. Thank you again! Brent

If you can rent one, or borrow one go nuts, but don't buy one just to prove theres a problem.  That is a very good idea by the way.2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

Alot of higher end stereo shops have them. Maybe meet the gm tech at one and use it. But it really depends on where you are. They are EXPENSIVE though.Certified Security Specialist

Always check info with a digital multimeter.

I promise to be good.

Tell Darwin I sent you.

I've been sick lately, sorry I won't be on much.

By the way I am with you on this one. I am one of those people that can hear higher pitch noises and they drive me crazy. Certified Security Specialist

Always check info with a digital multimeter.

I promise to be good.

Tell Darwin I sent you.

I've been sick lately, sorry I won't be on much.

Glad to hear you can hear these things, too! Wish I couldn't! Brent