Serato DJ is controlled by an analogue signal, there is no guarantee of what state that signal will be in by the time the software gets to interpret it. Therefore, Serato DJ needs to be able to handle a wide range of signals, and be configurable to use them optimally. Calibrating is just configuring the software to your situation. Calibration is equally important for both vinyl and CD users of Serato DJ.
There are two parts to the Serato DJ Control Vinyl: The directional tone, and the NoiseMap™. Listening to the control vinyl, the directional tone is the 1 kHz tone. The noise map sounds like random noise over the top of the tone.
The directional tone provides the current speed and direction of the record, while the noise map tells the software precisely where on the record the needle is currently.