Hi
The Bluetooth audio is a lot quieter when I play music from my iPhone 4 via Bluetooth than when I play a CD/ music on hard drive. On my old car you used to be able adjust the volume level for external device like aux so that you can ma ual adjust to the same volume so that you don't get a sudden blast of volume when you change audio source. Can you please tell me if there's such a setting as I can't find it.

Thx
3 series with I drive 2011