This snap runs under full confinement, which means it will not be able to access files outside of it's 'home' folder. Normally this would make the app pretty useless, right? So to get around this issue somewhat the snap also consumes the removable-media interface. But it is not hooked up by default. So after installing the snap do:
For versions of Ubuntu between 14.04 LTS (Trusty Tahr) and 15.10 (Wily Werewolf), as well as Ubuntu flavours that don’t include snap by default, snap can be installed from the Ubuntu Software Centre by searching for snapd.
Alternatively, snapd can be installed from the command line:
sudo apt update
sudo apt install snapd
Either log out and back in again, or restart your system, to ensure snap’s paths are updated correctly.
To install Subsonic, simply use the following command: