Making volume controller more fine My Sony Xperia has buttons to control the volume as most of other smartphones. The control is rather coarse, there are only 8 steps including max volume and silence. Especially for use of (Bluetooth) headphones this is silly coarse.

How can the volume adjustment more fine? I would like to have e.g. 32 steps here.

Edit: The device isn't rooted and I don't plan to do so.
No way to do so if your device isn't rooted.
Every app you find for the same will require root access.