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: OPUS-QUAD ASIO

Mixer Mode: External

Output Deck1: OPUS-QUAD ASIO: CH1

Output Deck2: OPUS-QUAD ASIO: CH2

Output Deck3：OPUS-QUAD ASIO : CH3

Output Deck4：OPUS-QUAD ASIO : CH4

■ Mac

Audio: OPUS-QUAD

Mixer Mode: External

Output Deck1: OPUS-QUAD: CH1

Output Deck2: OPUS-QUAD: CH2

Output Deck3：OPUS-QUAD : CH3

Output Deck4：OPUS-QUAD : CH4

*If you can’t select the correct choice because it isn’t displayed or an error has occurred etc., refer to "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 halfway, there’s no problem with the settings and operation.

If you don’t hear any sound from the headphones at this point, check the following:

6. Turn the Headphones [MIX] knob to the center.

7. Turn the Headphones [LEVEL] knob all the way to the left.

8. Turn the Headphones [LEVEL] knob slowly to the right.

3) Check the connection of speakers and headphones

See [Example of connections] in the Quick Start Guide for details.

Even if you’ve already connected them, reconnect them to ensure they’re correctly connected.

You can read the Quick Start Guide [here].