Add a note saying that the purpose of the "aplay ... Front_Center.wav" line is merely to test whether the sound works or not, rather than to test its quality.
Anecdotally, I had very static-y sound from the aplay command, which prompted me to incorrectly believe that my sound would not work with Mopidy. As it turns out, the sound works fine using Mopidy or gstreamer. This note will hopefully keep other Mopidy users from thinking their sound is broken when it is not. (I ended up installing armhf version and trying to use despotify, which didn't work, before coming back to Mopidy.)
