I have a 2010 528i without a Logic 7 no Navigation or CD changer. When I get into the car and put the key in I can here everything power up. I hear no noise over the stereo at no volume and all sources. Then I turn the engine on and the sound of data transfer like electrical feedback starts in the background. It is intermittent like "zzz zzzzzzzz zzzz zzzzzz zzzz" it doesn't increase with volume and can be heard with mute on or with any input. It goes away when I turn the engine off. I guess the best description would be like hearing a CD player searching for a track. I wonder if it is feedback from an engine part since it only happens when the engine turns on? It is on all interior speakers. Any help would be appreciated as BMW isn't helping much.

 

a 2010 E60LCI would have an amplifier for the Hi-Fi system, same location as the Logic7 amplifier would be. That amplifier has an analog input, like factory RCA cables, not optical input. It actually is possible for that amplifier to pick up noise from the input cables, and from any ground loops. The ZZZ description sounds like a audio or power ground loop. There are all kinds of things that could actually be wrong, such as software update, bad radio or amplifier, corroded wire plug/amp due to water, or a bad alternator/battery. I think you are going to need to find a tech that understands audio and BMWs. Is it under any warranty?

 

Actually I have this issue too. I have isolated the noise to the rear section of the car. I have a 2007 530xi with the logic 7. I put a sub (2 10") into the trunk and had to take it out because it make things a lot worse. I had power running directly from the battery to the additional amp. Let me ask you, does it change pitch if you rev the car? Mine did. Try driving around with the rear sats folded down. You will hear it immediately.I also put in a new battery. I did not have it coded to the car though.

 

I am running a good quality hi/lo electronic pass from the M-ASK speaker outputs to a JL Audio amp. It is not the amp though because if I have the key in the ignition and have the radio on the noise isn't there. It only starts after I start the engine. Then it starts after about 3 seconds after the engine starts. If it was the amp it would start when the amp powers up. Could the fan on the M-Ask unit or alternator feed back be a possibility? Not warrantied for electrical since it has been modified

 

The audio place says he thought he could hear the feedback in the engine compartment. He suggested alternator or coil issues?

 

I forgot to add to my previous post that I too only hear with the car running. With the engine off, no noise.