Adding a music layer to files

[livelonger8]

I'm unsure as to whether I should add a layer of music, music of which I enjoy, to a given file. Would this also cause suggestions playing in the background to appear subliminal, as I would mostly just hear the music?

If none of this works, could anyone suggest upon how to create subliminals from files that already exist; to add a layer of music to allow for an easier trance?