When I picked up the car a few months ago, I had a whine or buzz going through the stereo speakers relating to the rpms. I did some searching & it sounds like a ground loop issue. BTW - I have the Bose system.

The prior owner had a Sirus system installed and I recently added a mObridge unit. The whine didn't bother me much since you could only hear it under 35 mph, no radio & windows closed. Now that the weather is getting colder, I hear it more.

I took it to a stereo shop today that did the mObridge install to have them remove the Sirus system & possibly install a noise filter. They found the Sirus system was already removed (except for the little black receiver box) and they installed a filter. RPM whine still there, but reduced slightly.

They think the problem is either the head unit or most likely the amp is on its way out. Has this happened to anyone? I'm afraid to even check what the amp would cost to replace - it would probably be cheaper to replace the headunit & amp with a nice Alpine unit unless I can find a lightly used one.

One other item that is installed - Passport 9500ci. I don't think that could be causing this. Any ideas or suggestions would be appreciated.

 

I'd be surprised if the problem was anything but the added bits.
If it is the amp, it can be repaired. Replacement is not absurd price-wise either.

 

That's usually a symptom of a faulty ground connection.

 

+1 on the ground connection issue. In the install of the Sirius unit or its removal or the mobridge, something got hosed up or patched in in the wrong way with the ground wires, or the power wires possibly. Its never fun to hear the ignition system whining along....

 

FOUND THE PROBLEM! I stopped by a local stereo shop today and we figured out the problem. The prior owner had a Passport 9500ci installed. The speaker for the 9500 was mounted behind the center console under the stereo. In this location the speaker was picking up a frequency & then buzzing with the RPMs. We moved the speaker under the left kick panel - problem solved. Just for fun, they installed an isolater and all I hear is the engine now. Ahhhhhh.........

 

Good for you! Glad they got it corrected.

 

What is an isolator? A filter?

 

I have an 07 Targa 4s doing the same thing. Bose system with an after market Amplifier installed. The amp is drawing power off the battery. I had taken the car to a Porsche dealership to fix. All the grounds to the system were checked and are good. the navigation system died and when it was replaced the sound went away. When I picked up the car the sound was gone but a few weeks later I was driving on a rough road and the sound returned. The following link is what I recorded. Sound with the radio off or on.


Any ideas?? I'm bringing the car back to the dealership Monday for them to have another crack at fixing it.

Pete

 

If you hear a "whining" sound where the pitch rises and falls with the engine RPM, it is most likely alternator whine getting in through the power connection, or preamp wiring.
The usual and correct way is to put a capacitor and choke (inductor) comprising a filter in series with the positive lead to filter out the ripple getting in the system.

Several manufacturers made these filters.
Some casual reading:
https://www.crutchfield.com/S-xcRgir...ion_guide.html

 

PaulD,
The link provided is a good read on the subject. The ground to the new amp is good. The dealership said the alternator was also good. I'm scheduled to bring the car back to the dealership for another shot at this but is this in their wheelhouse or should I go to a high end car audio shop to do this diagnostic and work?

Pete

 

I think you have the right idea, a good car stereo shop would solve your problem because they see this often and they have the resources to fix it.
Chances are the dealer would send you car to a car stereo shop anyway because they don't normally deal with this type of problem.

 

Then again I'm leaning toward removing the aftermarket amplifier and if its working reconnect the Boze amplifier and return it to stock configuration. I believe the Boze unit is 75 watts and with the 911 cockpit size should be more than enough. Boze likely did extensive work designing the sound system for Porsche and the acoustics of the 911.

Pete

 

Just wanted to follow up on my 911. The dealership did confirm the aftermarket amp was causing the buzz. I had them remove the unit and return the system to stock after making sure the Boze amp was functional and it was. Picked up the car 2 weeks ago and it's now a dream to drive with no buzzing.

Pete

 

2009 C2S 178K miles

IMO, you did the right thing restoring to stock. I had a very reputable car stereo installer replace my system and he could not get the whine out. He tried everything. I even helped him... on a drive pulling out things re-wiring out there in a local neighborhood. Awful. He restored the system and gave my money back. This was a total mystery to him. Sometimes, it is what it is. He did two of my cars prior to this and I was totally satisfied before.

Peace
Bruce in Philly (now Atlanta)

 

Bruce,
Thanks. Destin Porsche did a great job dealing with an aftermarket add on situation. The first dealership in Montgomery refused to work on it for that reason. Open the frunk and there is no trace the unit was ever there. Costly but money well spent to have the cockpit experience match the driving experience.

Pete