Alright, this is weird. I updated the firmware to the newest (102/1.71/25) and switched to the ASIO driver (restarted mobius and pc). At first, everything sounded muddy and blah. I started playing a game I'm intimately familiar with and noticed that everything sounded almost like it was pitched down. Sound effects I had heard almost every day for years didn't match what my brain expected. I brought up the ASIO control panel and changed some buffer settings but didn't notice anything different, so I put it back where it was. But, now everything sounded like it was pitched up - voices seemed a little faster and definitely sounded higher pitched. I played music and started a stopwatch on my phone at the same time and made sure it was in sync for a few seconds. At 60 seconds according to the stopwatch on my phone, the media player on my pc had played over 63 seconds of music! I timed windows' clock and it matched my stopwatch exactly, so I know it's not a timing issue deeper-grained in my system. Perhaps a mismatch between expected sample rate (e.g. 44100 Hz) and actual sample rate (e.g. 48000 Hz)? Has anyone seen this before?
How can I switch back to the default audio driver for the mobius so I can see if that fixes the problem? Just uninstall "Audeze LLC USB Audio Device Control Panel"?
Edit: today seems back to normal. /shrug It was happening multiple days and persisted through restarts. I haven't messed with the buffer settings today though, will try that later.