Firstly, I love the music boxes both for the music as well as the beautiful designs that have been getting more and more intricate of late, so kudos to the design team for that.
However, I've noticed that the music from the music box is tied to the "effects volume" slider, both in the crown store preview as well as in the actual house. For myself and many other players who prefer to keep the effects volume low so that fight effects aren't super noisy, this makes music boxes really soft or inaudible unless we turn the volume back up.
Switching the volume channel to 'music' instead of 'effects' would make it more intuitive and solve the problem for the most part, but if it's possible
I'd suggest having a new volume slider just for music boxes. That way people who prefer to have music low/off for whatever reason but still want music box effects wouldn't be adversely affected either.
Hopefully this isn't too challenging to implement because I think it would greatly boost the functionality and appeal of music boxes. If you do a search for "music box" you'll see a couple of threads asking about no/little sound from music boxes which shows that this isn't an uncommon problem. Thanks

my current audio settings - music boxes are really soft compared to in-game music