1. Verify the output setting on your computer and check if the Saturn I & II audio interface is connected and selected as an output device.
2. Turn up volume for Headphone-Out and Main-Out.
3. Verify the Direct Monitor position on your Saturn audio interface.
USB: To hear of your computer playback.
DIRECT: To hear of your input from Input1 & 2.
4. Connect Main-Out/Headphone-Out to a different monitor or headphone set to rule out issues.
5. Use different audio cables to test if a cable is faulty.
*Since many problems are frequently identified as NTF (No-Trouble-Found) and can be resolved through a few additional checks, we recommend that when you encounter any issues, always double-check all cable connections, the functionality of the power cord/power socket, the volume control level on the CPA loudspeakers, or the input source gear, etc.
Further Reading:
Common Audio Cable Problems and Solutions:
https://www.prosoundweb.com/six-common-audio-cable-problems-and-solutions/