HI, since Connor is away, I will be continuing the investigation.
Unfortunately, I was not able to reproduce the issue. Does the sound only play faster than expected on Harmony OS platform? Does this issue occur with all events or just specific ones? Would it be possible to elaborate on how to reproduce the issue?
You could consider using FMOD Engine | 7. Core API Reference | | Channel::setFrequency to directly reduce the frequency, setting it to half of a typical 44100Hz rate (22050 Hz) to see if it slows down the playback speed.
Alternatively, you could enable fast mode on the HarmonyOs platform to see if it helps.
I will link the detailed process here:
Hope this helps! let me know if the issue persists.