Sound comes out of my headphones or speakers incorrectly. [rekordbox]

There are three things to consider: settings, operation and connection.
Please check each in the following sequence:

1) Confirm the audio output destination setting
1. Open rekordbox Preferences.
2. Click [Audio].
3. Check that each item is selected as follows:

■ Windows
Audio: XDJ-RX3 ASIO
Mixer Mode: Internal
Master Output: XDJ-RX3 ASIO : MASTER
Headphones Output: XDJ-RX3 ASIO : PHONES
Mixer Mode: External
Output Deck1: XDJ-RX3 ASIO: CH1
Output Deck2: XDJ-RX3 ASIO: CH2

■ Mac
Audio: XDJ-RX3
Mixer Mode: Internal
Master Output : XDJ-RX3: MASTER
Headphones Output: XDJ-RX3: PHONES
Mixer Mode: External
Output Deck1: XDJ-RX3: CH1
Output Deck2: XDJ-RX3: CH2

*If you can’t select the correct choice because it isn’t displayed or an error has occurred etc., refer to [Troubleshooting -rekordbox) > "I can't set [AUDIO] in the rekordbox Preferences correctly."].

2) Check the volume level operation
1. Play a track.
2. Set the TRIM knob to the center (12 o’clock).
3. Slide the channel fader to the top.
4. Slide the crossfader to the center.
5. Turn the MASTER LEVEL knob to 2 o'clock.
If the MASTER LEVEL indicator lights up more than half way, there’s no problem in the settings and operation.
If you don’t hear any sound from the headphones at this point, check the following:
6. Turn the HEADPHONES MIXING knob to the center.
7. Turn the HEADPHONES LEVEL knob all the way to the left.
8. Press the MASTER CUE button.
9. Turn the HEADPHONES LEVEL knob slowly to the right.

3) Check the connection of speakers and headphones
For details, see [Connections] in the Quick Start Guide.
Even if you’ve already connected them, reconnect them to make sure they’re properly connected.
You can read the Quick Start Guide [here].