CITROEN C4 Handbook page 214

Touch screen BLUETOOTH audio system
Some telephones offer display options.
Depending on the settings chosen, contacts can
be transferred in a specific order.
► Modify the telephone directory display
settings.
Settings
When the treble and bass settings are
changed, the ambience is deselected.
When the ambience is changed, the treble
and bass settings are reset.
Selecting an ambience imposes the treble and
bass settings, and vice versa.
► Modify the treble and bass or ambience
settings to obtain the desired musical ambience.
There is a difference in sound quality
between audio sources.
To allow for optimal listening quality, the sound
settings can be tailored to different audio
sources, which can generate audible differences
when changing source.
► Check that the sound settings are appropriate
to the sources listened to. Adjust the sound
functions to the middle position.
When the engine is off, the system switches
off after several minutes of use.
When the engine is switched off, the system's
operating time depends on the state of charge of
the battery.
The switch-off is normal: the system
automatically goes into energy economy mode
and switches off to maintain an adequate charge
in the battery.
212
► Start the vehicle's engine to increase the
charge of the battery.