As a follow-up on this post On-topic & Off-topic, I wonder if some of the problem related to activity is related to this group's name.
Myself I am not sure why Music Fans has low participation (though I think Arts/Culture will always have lower participation than Science/Math/IT due to the nature of SE), but I wonder about the name "Music Fans" (the fan part).
Like saying "science fans", I would really have no idea what the focus is, or whether it would be a good place to go with my question.
To me, this is far too vague as to what this community is about (other than music that is).
As we know there is the existing community "Music: Practice & Theory" which is at a more professional level of music performance or studies.
Now when I think back to my school years, we had music performance groups (including myself), but for other students there was a class titled "Music Appreciation", which taught music basics and relevance to popular music those students were familiar with.
I can't say "Music Appreciation" would necessarily be better, but I would really recommend some term better that "fans" that would help people understand what the focus of the community is.
Taking a quick looks at the tags used so far, there is higher usage for "lyrics", "history", "genre" and "terminology".
"Terminology" could fit into "Appreciation", and "genre" and specific band/tune/chart related questions could fit into "history".
Admittedly this is generalizing somewhat, but for the sake of a more focused community name may be worth considering.
So my initial take on this would be:
Music Appreciation and History