On macOS Tahoe (26.x, tested on 26.3 / M3 MacBook Air), system audio gradually degrades over time — volume drops significantly and sound becomes muffled across all outputs (built-in speakers, Bluetooth headphones, etc.) at the same volume setting.
- Onset is intermittent: anywhere from hours to days after a clean reboot.
coreaudiodsometimes shows elevated CPU usage during the degraded state.- A full reboot reliably restores normal audio. The issue then eventually recurs.