Want to mix and scratch like a professional DJ? To be a good DJ you need to understand the concepts of mixing tracks, adding cool effects, and of course you need a good sense of rhythm to line up the beats. This how to video explains how to use the roll feature on a DJ mixer. This video shows you how to use the FX from a mixer with a vinyl turntable. Watch this DJ tutorial so you can learn how to use the roll feature on a DJ mixer.