When I recently switched to Manjaro, I was happy that I could use the native MuseScore app instead of the AppImage, and that performance issues were gone.
But since last week, I could not play back any MuseScore file anymore. Even worse: As long as MuseScore was started, ALL the playback devices only produced a crackling and distorted sound with an echo of about 1.5 to two seconds.
PulseAudio Audio Latencies
After digging a bit in the MuseScore forums, I found that MuseScore sets the desired target latency for PulseAudio in a wrong way. The effective desired value was 0.5ms, which is way too low for PulseAudio to handle.
Latency workaround
Luckily, a workaround was quickly found. You can set the correct audio latency via an environment variable like so:
PULSE_LATENCY_MSEC=30 mscore
If this works for you and you want to apply it permanently, edit your /usr/share/applications/mscore.desktop
and edit it like so:
Exec=env PULSE_LATENCY_MSEC=30 mscore
Conclusion
MuseScore works fine again and no sound is distorted anymore.