I apologize for the crudeness of the video, just did this during my lunch break. This should help resolve many issues no matter if your using FPP, xSchedule, built in audio, Sound Blaster, speakers or any FM transmitter. I forgot to mention, turn off any EQ, and turn down or off any mic input.
Link to 30 second 100hz audio test file at 0db: drive.google.com/file/d/1JEft...
26 ноя 2018