UPDATE: If using with buildfiles, add this line to the bottom of your Sound Room Editor.event (or equivalent file): csvmacro000(0xFFFFFFFF,0,0,0)
This adds the table terminator that otherwise is missing, causing the game to hang when entering the Sound Room.
For the 0 people using this with FE6, it should end up as csvmacro000(0xFFFFFFFF,0,0) instead, since there’s one less entry (though I haven’t tested this, it’s just a theory).