No sounds in Cardboard build

I've just loaded Daydream Preview and try to build Cardboard version of my Gear VR application. My application loads mp3 from persistent storage, and Gear VR version plays them well. The Cardboard version of my app (built from the same sources as Gear VR is) doesn't play sounds. It perfectly loads images from the persistent storage folder, so it seems that there is some issue with sounds playback.

Yet another issue - headtracking in Gear VR build is fast and smooth. But on the Cardboard version headtracking is jerkily, like ~5-8 FPS. The app is light enough - it's just sphere with 360 photo on inner surface and camera inside this sphere. I run both applications on Samsung Galaxy S7 Edge.

Could you please help me to fix issue with sound and improve the headtracking/rendering performance.

 

No ideas about the sound issue, but re: the headtracking, Gear VR is always going to feel smoother than Cardboard because Gear VR is using its own (way better) IMUs than whatever your phone has, and Gear VR is doing the whole asynchronous timewarp thing (which Daydream will also do, but not Cardboard).