
This was explained in Macross 7,
. It's the passionate power of rock and roll! Spiritia/Sound Energy capable of generating and replenishing the spirit of all living things. The sheer will of someone singing at the mountain trying to move it with his song or trying to change the world through music is what separates a minstrel (professional) from bard (vocational).
Macross 7 clips of passionate singing and song energy
It's also likely that the connection to the Echo is what turns that passion into power. That's how I'd look at it, anyway.
... Actually, the more I think about the Final Fantasy world mixed in with Macross Idol/Songstress music sensibilities, the more I really like it, hehe.

Macross 7 clips of passionate singing and song energy
It's also likely that the connection to the Echo is what turns that passion into power. That's how I'd look at it, anyway.
... Actually, the more I think about the Final Fantasy world mixed in with Macross Idol/Songstress music sensibilities, the more I really like it, hehe.