I'm going to try to be as factual as I can. Up front I think it's worth mentioning that I have previously experienced USB Audio driver crashes which were caused by a buggy Nvidia driver. Details here:
https://forum.fractalaudio.com/threads/fm9-usb-firmware-v-1-02-release.194146/page-2#post-2533961
Having started getting issues with USB driver v5p68b I reverted to v5.58. Everything seemed ok again for about an hour or so. I switched the FM9 off but left the PC running. A short while later I fired up the FM9 again, staying on the same Preset I was on when I switched the unit off. There was no instrument (guitar) sound from either Output 1 to the monitors, or through the headphone output jack. The guitar was plugged into Input 1, same as always.
No sound via USB Audio from the PC either. Nothing from YouTube in Chrome using Windows Audio, nothing from the DAW using ASIO.
At this point I could have just rebooted the unit, but I thought it was strange and wanted to try to understand what might be happening, so I added the Output 2 block to the Preset, and connected the XLR leads to L/R on output 2 on the unit. At which point the unit started outputting an extremely loud and distorted signal via output 2 through monitors and headphones.
You can hear it in this video. This is the guitar into input 1, but just incredibly loud and distorted:
Video Zip 1
I then turned the guitar volume down and recorded the continuing distorted noise coming out of output 2 through the monitors (I didn't check the headphones at this point, the noise was too distracting and I forgot). This is the distorted signal coming from the midi instrument (Zenology) monitoring in the Studio One DAW via the USB Audio coming out of output 2 on the FM9 into the monitor speakers:
Video Zip 2
Finally I played a few notes via midi on the Zenology instrument, again via the midi monitoring in the Studio One DAW via the FM9 USB Audio coming out of output 2 on the FM9 into the monitor speakers. You can hear how overloaded and distorted the signal is (in addition to the general noise and feedback which I've already mentioned):
Video Zip 3
I've also attached the Preset I was using (
after adding Output 2 and exporting), just in case it helps, although I don't think the specific Preset is of significance here.
Just for the sake of completeness it's worth mentioning that all the USB inputs are set to 0dB in the FM9 Input settings, and have been for a long time.
I've now reverted the USB Audio Driver even further to v5.30. So far (another hour or so), no issues... I will report back in a few days.