If there's a existing issue, please link to it. If not, provide fill out the same information you would in a normal issue - reproduction steps for bugs, rationale for use-case.
If you're working on CraftOS, try to write a few test cases so we can ensure everything continues to work in the future. Tests live in src/test/resources/test-rom/spec and can be run with ./gradlew check.
Frustratingly, this only fixes the lag that occurs the first time you play audio after entering the world, and the same problem persists as soon as you play again.
Keep it synchronized with CC: Tweaked, otherwise it will cause playback delay.
Discussion
A quick checklist
src/test/resources/test-rom/spec
and can be run with./gradlew check
.