Pioneer Dj DDJ-FLX4 Portable 2-Channel rekordbox DJ and Serato Controller (Graphite) - Manual (Page 43)

Connections
43
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Connecting via Bluetooth
You can connect your mobile device via Bluetooth.
Sound does not output from the unit via Bluetooth. Instead, connect a
cable from the mobile device to an audio output device before use.
 Connecting to an audio device (example 1)
In this example, the master sound plays in stereo and there is no sound
output to the headphones.
(1) Speaker with built-in amplifier, etc.
(2) USB/Lightning to 3.5 mm headphones jack (not supplied)
DC 9V 3A
(1)
(2)