I have a problem that when I use Spotify in my phone with my new Bluetooth headphones (Valco), the interval is lacking levels. Adding volume from too low volume to next step is too big, that is, volume becomes too loud. It kind of lacks few levels. I tried to listen same song from YouTube and there the volume had enough levels. So, the system volume adjustment works fine, but in Spotify app it has this strange jump. In higher volume levels the interval are not rising as this steep.
I hope that I was able to describe the problem clearly enough.