Here you can adjust the noise threshold. A threshold is a lower limit, below which a process will not occur. In the case of Serato DJ Pro, the noise threshold is the limit below which the input signal will not be interpreted as control signal; in other words if it’s below the threshold, it is considered noise and ignored.

This setting is necessary because a stylus is very sensitive, and will inevitably pick up noise from the environment as well as the signal on the record, especially in the noisy environment of a live show.