For Windows - Roland SP-404MK Reference Manual

Inputting Audio from a Computer or Mobile Device (USB AUDIO)
The SP-404MKⅡ can receive audio input from a computer or mobile device (such as a smartphone or tablet).
Configuring the OS audio settings
You must make the appropriate settings on your computer when inputting audio from a computer to the SP-404MKⅡ.
For Windows
1
Open the Control Panel.
2
Click the "Hardware and Sound" icon, and then click the "Sound" icon.
If the panel is displaying as icons or in classic view, double-click the [Sound] icon.
3
Click the [Playback] tab.
4
Click "Speakers SP-404MKII-G," and click the "Set Default" button.
5
Click the [OK] button.
For macOS
1
Open the System Preferences.
2
Click the [Sound] icon.
3
Click the [Output] tab and select [SP-404MKII-OUT].
4
Close the System Preferences.
Enabling audio from a computer or mobile device
1
Connect your computer to the SP-404MKⅡ with a USB cable.
2
Press the [EXT SOURCE] button on the SP-404MKⅡ.
3
The [EXT SOURCE] button is lit. Input the audio from your computer or mobile device into the SP-
404MKⅡ.