Audio is distorted when output device and BackgroundMusic device have different frequency

[choco]

I noticed that the audio being reproduced was distorted when connecting my headphones. I discovered in the Audio MIDI Setup that my headphone had a set frequency of 48kHz, instead BackgroundMusic device had a frequency of 44khz. Syncing them seemed to solve the distortion

[choco]

Actually I got this the other way around.

1. Headphones disconnected, both Background Music Device and Buit-in Output devices are set to 44kHz
2. Connect the headphones, Headphones Device (Built-in output) still set to 44kHz, Background Music Device switches to 48kHz, sound becomes distorted/not synced
3. Disconnect headphones, Built in output still 44kHz, Background Music still 48kHz.

Syncing the frequencies solves the issue.

[kode54]

Extending this issue.

When a game changes BackgroundMusic device's sample rate, BackgroundMusic app does not forward this change to the real output device, or to the system sounds output device, for that matter.