How can I unlock more songs in Theatrhythm: Final Fantasy?

Question

I've got a decent amount of playtime under my belt in Theatrhythm: Final Fantasy so far. I have over 12,000 Rhythmia accumulated, I've cleared 10 out of the available 13 Series courses, I've cleared 22 different Dark Notes, I've SS'ed several songs in Challenge mode and cleared a number of Ultimate scores.

Despite all of that, however, I've only been able to uncover one additional song, in the hidden "Encore" category. According to the main menu, this brings my total Challenge Mode song count up to 40, when the Museum mode shows that there are 77 music tracks total. I've played a number of new songs (as well as otherwise-unplayable tracks such as OP/ED themes) as a part of Dark Notes in the Chaos Shrine, but can't seem to access them outside of that mode at all.

Are there more songs I can unlock for Challenge Mode, and if so, how? Additionally, is there a way to permanently unlock Chaos Shrine songs for regular play?

Answer 1

Starting at 10,000 rhythmia, and every 5,000rm after that, you get a new song. There is one exception: you get Battle 1 (FFVI) at 27,500rm.

Answer 2

As for farming rhythmia, I find playing ultimate scores seems to work the best. I currently have 31000, and playing awakening (FFXI BMS) nets you ~ 175 rhythmia per play. I was playing without shantotto in my team, so you're looking at 200+ per play. Having a team full of males/females helps slightly, too, giving you +10 rhythmia.

You start unlocking chaos shrine scores at 27500 rhythmia. For these ones, new songs seem to be unlocked every 2500 points, instead.