Things you will need:
Original Version of Song
Instrumental of Song
Multi-Track Audio Editing Program (I use Adobe Audition, but any program that can rip CD to WAV, edit the WAV and multi-track them should work)
I'm lucky enough as well as many other DJs out there to get free promo CD singles and Vinyl singles sent to me every week from Universal Records. This will work best if you have the CD single. Vinyl rips are not recommended because any fluctuation of the turntable speed can throw the whole thing off. This should also work with DigiWaxx mp3s you download, but it may not be as good since encoding from mp3 can give varied results.
Instructions:
Rip the album version and instrumental version from CD as a standard Uncompressed WAV file.
You should have 2 files which are normally the same length and size.
Open up Audition and line them up PERFECTLY. Zoom in and make sure the wave forms peak at the exact same spots. This part is KEY.
Play the tracks, they should play as normal, maybe a little loud, since you could be peaking past 0db.
INVERT either file, doesn't matter which one, but only choose 1 file.
Now when you look in the zoomed multi-track view, the wave files should peak at the exact opposite spots.
Now play the tracks, and you should just hear the vocals/acapella. Export that to a new file and save it as your acapella.
Why does this work? Since the wave form phase for the instrumental and Original version are exact opposites, they cancel/phase out each other and you are left with the vocals.
Why is this not working for you? You may not have the wave forms lined up correctly. If using vinyl, a slight fluctuation will mess up the wave form. If using mp3s, encoding may be slightly different. It's also possible the instrumental was EQ'd or mastered differently than the original making which may make the waveforms line up incorrectly.
