Hi 05c47,
I think this is a MicroBrute related question.
If you can hear the MicroBrute sound from your headphones, your audio card may be not configured properly or your cable (or connector) if faulty.
Have you tried connecting your MicroBrute headphone output to your sound card (just for test purpose)?
Anyway, this is not a BeatStep Pro issue.
Best, Y.