[MC-146721] Stereo sounds don't become quieter when the player walks away

Mod Notice

While we are on topic of resource packs, please make sure your custom sounds have same number of channels as vanilla ones - otherwise you may have problems with volume and position (see OpenAL specification, section 5.3.4 for reason)

Rule of thumb: if you can move away from sound (i.e. it plays in world at certain position), keep it mono. If it's UI, background music or ambient sound it can be stereo.

– [Mojang] Bartosz Bok in this tweet

After rewriting of the sound engine, when playing vanilla sound using /playsound command it gets quieter when the player walks away, but when playing custom sound from a resourcepack, voluming down stops working. I am attaching a video showing the problem and sounds.json