EMS VCS 3 is a virtual control system developed by the company EMS. It is used by many professional DJs, producers, and musicians to control their music production and performance. It works by connecting a computer to a MIDI controller, allowing users to control their music production and performance with the controller. It has a variety of features, including a step sequencer, a mixer, a sampler, and a library of sounds. It also has a variety of effects, including reverb, delay, and distortion. Additionally, it has a variety of tools for creating and editing MIDI patterns, as well as a variety of tools for creating and editing audio.