FMOD_INIT_VOL0_BECOMES_VIRTUAL causes volume dropping

I’m having a weird bug with virtual sounds. When I use FMOD_INIT_VOL0_BECOMES_VIRTUAL, some events lose volume (around 10db down) when they become active again.

Here are the details:

  • I have a Gameplay Bus and a Music Bus, they are both independent (no compressors or sidechains), and both output to a Master Bus.
  • When I go to the Pause menu, I set both of them to 0 using (setFaderLevel).
  • When I go back to the game I set them both to 1.
  • Every now and then the Music Volume goes down (around 10db at the mixer Input) when going back to game from pause menu.
  • The music is at 50% (Vorbis) and has no params or automations and no AHDSR or any random modulation.
  • All other gameplay sounds are ADPCM at 44.1khz
  • If I turn the music bus down to 0 and keep the gameplay at 1, then the bug doesnt happen. It just seems that when all sounds go to Virtual and wake up together at the same time, the bug happens.
  • I removed all compressors and sidechains, and it still didn’t help.
  • If I remove FMOD_INIT_VOL0_BECOMES_VIRTUAL the problem disappears.
  • The issue happens very rarely in the game. So to get 100% repro, I had to add some code in my audio update to setFaderLevel to 0 and 1 alternately every 500ms for both busses, and that gave me 100% repro .
  • The bug happens on both Mac and PC and on both 1.05.00 and 1.05.08.

I can probably dig deeper into it and try to reproduce it in a minimal repro case using one of your examples, but I wanted to ask you if this rings any bell, or if you have some debugging hints for me before I do more time consuming work.

There were some bugs associated with virtual voices and volume that were fixed in 1.05.09. Could you update to the latest version and try again? If it is still a problem then we can follow up at