I recently got some speakers installed in my 02'Benz E320.I have no factory speakers or amp connected.I'm hearing a whistling or buzzing sound coming thru my music when my volume is lower than 20 when my car is on.The sound goes away when my car engine is off and my stereo is on when the key is in position 2(Position before starting up).The sound gets louder the faster I go and quiets when I let off the gas.
To me it seems like a small electrical problem but I dont know to much about car audio.Its like engine noise is interfering w/the music or going thru some wires causing my music to have a distorted sound at low levels.Ive heard of Mercedes having some "speed sensitive sensor" that could be turned off or overridin.Any help of this matter on where I can get it fixed at or how I could do it myself is greatly appreciated.[/align]

 

As you have figured out, your problem has two separate issues. The interference when the engine is on could be a lot of things. I would go back to whoever installed the speakers. If that's not an option then a good local radio shop who specializes in MB radios or (dread) the dealer.

The second issue is GAL. This is a feature that increases the volume of the radio according to your speed. Some Becker radios have a setup menu and it can be set there. If you have the COMMAND system, check the menus or your manual. Usually, it can be set to OFF or at a point, say 1 to 10, when it will kick in. I've never understood this feature. MB makes one of the quietest cars on the road. Maybe with top down doing 130 on the Autobahn it would be useful.