DDJ-SP1 Add-On Controller for Serato DJ and rekordbox dj The Pioneer DDJ-SP1 Serato Sub-Controller is a USB bus-powered performance controller designed for DJs who use Serato DJ or rekordbox dj software and want additional performance pads, knobs, and buttons for triggering samples and applying effects. The unit features 16 velocity sensitive trigger pads, eight per channel, with functions such as In, Out, Loop Active, Reloop/Exit, Save, Slot Up, and Slot Down. The output level of the pads can