See also:

BMW Assist or ConnectedDrive
...

Operation
Adjusting the volume Turn the knob until the desired volume is reached. The setting is stored for the remote control currently in use. The vehicle automatically adjusts the volume of the microphon ...

HD Radio™ reception
Many stations broadcast both analog and digital signals. If a digital radio network is available, these stations can be received digitally and thus with better sound quality. License conditions ...