There are 3 things to consider: settings, operation, and connection.
Please check each in the following sequence:

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

■ Windows
Audio: DJM-S7 ASIO
Mixer Mode: External
Output Deck1: DJM-S7 ASIO: CH1
Output Deck2: DJM-S7 ASIO: CH2
Output Sampler Deck: DJM-S7 ASIO: SAMPLER VOL

■ Mac
Audio: DJM-S7
Mixer Mode: External
Output Deck1: DJM-S7: CH1
Output Deck2: DJM-S7: CH2
Output Sampler Deck: DJM-S7: SAMPLER VOL

*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. Slide the headphones cue fader to the center.
9. Turn the HEADPHONES LEVEL knob slowly to the right.

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

The installation of the driver software might be incomplete or the connection might be causing a problem.
If you’ve already installed the driver software, try again using the following procedure:

■Windows
1. Close rekordbox and disconnect the DJM-S7 from your computer.
2. Open the control panel (or [Start] > [Settings] > [Apps]) and uninstall [DJM-S7 Driver].
3. Close Windows.
4. Disconnect other USB devices, USB hubs, etc.
5. Start Windows.
6. Download the driver software from [here].
7. Install the driver software again.
　*An error will occur when the license agreement screen is displayed and you try to proceed without clicking "I agree".
8. Connect the DJM-S7 to another port without using a USB hub, etc.

If you still can't set [AUDIO], the problem might be caused by operating system settings, etc.
See case 3 and 6 in the guide [here].

■Mac
Follow the instructions in the guide [here].

If you still experience the problem, it might be caused by operating system sound settings, etc.
Remove all other USB devices from your Mac, uninstall the virtual audio device etc, and restart the Mac.

The DJM-S7 might not be not properly connected, or rekordbox or your operating system might not be able to recognize the unit as a controller.

■ Operating system
Mac users, follow the procedures in the guide [here].

Windows users, follow the steps in Case 5 in the section of this guide [here].

■ Others
You might solve the issue by doing the following:
- Disconnect any USB hubs and connect the unit directly to your PC/Mac.
- Disconnect any other USB devices.
- Quit all other applications.
- Connect the unit to a different USB port.

If the volume level is too high, the sound may be affected by distortion or clipping.
Play a track and follow these steps:

1. Check the channel level indicator on the DJM-S7.
Adjust the level with the [TRIM] knob so the channel level indicator lights up around [0] dB (so the red doesn't light up) at the loudest part of the track.
2. Check the master level indicator on the DJM-S7.
With the channel fader at the top, adjust the level with the [MASTER LEVEL] knob so the master level indicator lights up around [0] dB (so the red doesn't light up) at the loudest part of the track.

If the distortion and sound clipping doesn’t improve, the output level might exceed the allowed input level of the connected speakers or amplifier.

In this case, you'll need to lower the output level using [MASTER ATT.] in the Utility settings.
For details, see the Instruction Manual > [Settings] > [Utility settings].

If sound skipping, sound cutting, or noise occurs, see [Troubleshooting_rekordbox]> "Sound skips, cuts, or is affected by noise. Why is this happening?".

You can read the Instruction Manual [here].

There are 4 main factors that can cause this and there are 4 possible countermeasures:

■ Dust on the needle of a turntable when using DVS control
Dust may accumulate at the tip of the needle, resulting in sound skipping, etc. In this case, remove the dust from the tip of the needle.

■When buffer size is the cause
If the buffer size is too low, sound cutting or unwanted noise may occur.
You can adjust buffer size in rekordbox [Preferences] < [Audio] < [Buffer size].
(Windows users can adjust it in [Preferences] < [Audio] < [Setting Utility] < [ASIO tab].)
First, select a large value such as 1024. If the problem clears up, adjust to a value small enough that you don't experience a delay in operation (latency).
*The appropriate value depends on the system environment.

■When the connection or other equipment is the cause
An unstable connection with your PC/Mac might cause these problems.
To solve this, shut down your PC/Mac and disconnect all other USB devices and USB hubs. Then, connect the DJM-S7 directly to a different USB port.

■When your system (PC/Mac) is the cause
Doing the following might solve the issue:
- Quit all other applications.
- Disconnect from the internet and exit security software.
- Turn off wireless connections such as Wi-Fi or Bluetooth.
- Turn off power-saving settings.

If your computer's system doesn’t meet the requirements of rekordbox, it might cause the issue. See details on system requirements [here].

If you can't play audio files with rekordbox, check if the following applies:

• The file format is one that's not supported by rekordbox.
• Only certain applications can play the audio file, e.g. the audio file was downloaded from Apple Music, etc.
• The location of the audio file has changed.
• The audio file is damaged. For details, see [Management] and [Music files that can be loaded and played (file formats)] in the rekordbox Instruction Manual. You can read the rekordbox Instruction Manual [here].

When the DJM-S7 is used with rekordbox, the file formats that can be played differ depending on rekordbox modes.

For example, ALAC and high-resolution files can play only in Performance mode.
*In Performance mode, rekordbox loads and plays music. Therefore, you can play only files in formats that rekordbox supports.

For the file formats supported in Export mode, see [Supported music file formats] in [Before you start] in the Instruction Manual.
You can read the Instruction Manual [here].
For the file formats supported in Performance mode, see [Music files that can be loaded and played (file formats)] in the rekordbox Instruction Manual.
You can read the rekordbox Instruction Manual [here].

There are 4 main factors that can cause this and there are 4 possible countermeasures:

■ Dust on the needle of a turntable when using DVS control
Dust may accumulate at the tip of the needle, resulting in sound skipping, etc. In this case, remove the dust from the tip of the needle.

■When the Windows built-in sound device setting is the cause
See case 4 in the troubleshooting guide [here].

■When the connection or other equipment is the cause
An unstable connection with your PC/Mac might cause this problem.
To solve this, shut down your PC/Mac and disconnect all other USB devices and USB hubs. Then, connect the DJM-S7 directly to a different USB port.

■When your system (PC/Mac) is the cause
Doing the following might solve the issue:
- Quit all other applications.
- Disconnect from the internet and exit security software.
- Turn off wireless connections such as Wi-Fi or Bluetooth.
- Turn off power-saving settings.

If your computer's system doesn’t meet the requirements of rekordbox, it might cause the issue. See details on system requirements [here].