BenQ Z2 - Manual (Page 55)

Using Your Phone 39
Pressing (Back) or will close the MP3 player screen
without stopping the music (the music will continue in the
background).
The phone's MP3 player supports both Constant Bit Rate (CBR) and
Variable Bit Rate (VBR).
MP3 player settings
Adjusting volume
Press the volume key on the left edge of the phone to adjust volume.
While music is being played in the background (after pressing
(Back) or to close the MP3 player screen), long-press the
volume key to adjust volume.
Setting the EQ (Equalizer) mode
Press (Option) and select Set EQ to choose your preferred EQ
mode that will influence the sound during playback.
Producing 3D sound effects
Press to produce 3D audio effects during playback.
Setting up A-B Repeat
The MP3 Player supports A-B Repeat--continuous repeat of playback
between selected points--which is ideally suited for use in languag
learning.