|Adobe Audition (images from adobe.com)|
After you install your adobe audition in your computer, now run that software. And you will look screen with a lot of track, panel and etc. To remove vocal from a song is not hard, first step is import your audio file usually *.mp3 or *.wav extension. The you will look screen importing process. After you finish importing your sound, there are will showed a music name on library. Then just click edit view, then click favorites and vocal remove. Click that and now you have karaoke instrumental, export and play it.