You'll need to mix it in another program. (First one that comes to mind that's free is Audacity.)
"Pretty" IGASIO.
disillusion (VOCALOID KAITO)
Fate/stay night OP I think. From IGASIO's comment, in this song "KAITO" is not trying to mimic the original song as close as possible, but singing it how "KAITO" wants to sing it instead.