Really? I recall setting up a completely clean rom and trying romi's addmusic and getting straight up bare echo with no -se option to work awhile ago. I specifically remember everything was fine until I ran -se on my rom, at which point I noticed it started putting stuff in the echo buffer space, which I assume is something related to sound effects or the nspc patch hacks (probably sound effects actually, because the sound effect data is stored right there, before the echo buffer at $6000 in aram). Then starting the hack up, exactly what I expected to happen happened. Once I entered the stage with the echo, the sound crackled because it was reading the data in $6000 like it was echo data.
I don't remember if carol's more.bin has the same problem.
I don't remember if carol's more.bin has the same problem.