I remember they used a remastered version of gaiden's opening theme in the FE direct reveal trailer.. did they not put it in SoV? I went through the sound test multiple times to find it but couldn't. Man, I was looking forward to that. Am I missing anything, is it somewhere I can't seem to find?
As you know, it's common for FE games to have the Sound Test feature. In fact, i think every game has had it since either Thracia or Binding Blade. Anyway, to unlock Sound Test in Echoes, what you have to do is, at the title screen, press up, down, left, right, up on the D-pad. You'll hear a little 8-bit jingle if you did it right.
Sound Test will then be found in Extras.