You'll need instrumental and vocal versions of the song,but if u're remixing arabic songs forget about the instrumental coz u won't find it.
but there's a trick,find one bar of music with NO vocals and the same or very close to the one with the vocals (from the same song) copy and paste it over the vocals with "inverted channel",if u're using soundforge copy>edit>paste special>mix, now check the "inverted data"...
hope this help.cheers!
EDIT:maybe i can explain it better when i'm sober
