System volume slider control – If on will allow per page volume control of playback for iTunes library files. This is not needed if you use imported mp3 files from dropbox, airdrop, email and link them to a page.
Metronome output – You can choose to output the metronome sound in the left or right channel, or both (center).
Note: if this is on, visual on screen volume will not be present. You will need to choose the music menu Set Player Volume to see the current volume level.
Bluetooth Audio– If you need to send the audio of unrealBook to a Bluetooth or Airplay device, turn this on. Note that this will disable the built in recorder.