Pioneer Dj DDJ-FLX4 Portable 2-Channel rekordbox DJ and Serato Controller (Graphite) - Manual (Page 32)

Part names and functions
32
En
4 BEAT  button
Press:
Increases the number of beats for synchronizing the Beat FX sound each time
the button is pressed.
[SHIFT] + press:
Sets the Beat FX Tempo mode to BPM Tap mode. The BPM used as the basis
for Beat FX is set in time with your tapping of the button.
5 BEAT FX LEVEL/DEPTH knob
Adjusts the parameter of Beat FX.
6 BEAT FX ON/OFF button
Press:
Turns Beat FX on/off.
[SHIFT] + press:
Turns Release FX on/off.
 Using Serato DJ Lite
1 FX CH SELECT switch
Slide:
Changes the channel that effects will be applied to.
2 FX SELECT button
Press:
Changes the FX each time the button is pressed.
[SHIFT] + press:
Changes the FX in the reverse order each time the button is pressed.
Serato DJ Pro