The Pioneer DJ DDJ-FLX4 + Pioneer DJ HDJ-CUE1 is a professional DJ set that's easy to use. You connect the controller to your tablet or laptop. Install the included apps or software and you can start mixing right away. You learn about the most common DJ terms and about the controller's functions. On the laptop, you'll see what you need to do and you'll perform on the controller. You connect the controller to your laptop or tablet to use its sound card. The controller itself has no sound card. With the headphones, you listen to what you're mixing. The headphones have a 5Hz to 30.000Hz frequency range, so you hear detailed sound. This makes it possible to listen critically to what you're mixing.