Pioneer has based the layout of the CDJ-400 on its industry standard front loading CD deck, the CDJ-1000. Sitting proudly on the top facia is a pressure-sensitive jog dial, which can be toggled between Vinyl mode and standard CDJ mode via an illuminated button to the right of the jog dial. And just like the CDJ-1000, Vinyl mode allows you to scratch the audio playback just as though you were scratching a real record. When you touch the jog dial with your finger the music stops. Let it go and the music continues playing. Pitch bending in Vinyl mode is achieved using the outer edge of the jog dial only. Switching to CDJ mode, however, allows pitch bend to be performed with any part of the jog dial.
The jog dial is of the passive kind, which means it doesn't automatically rotate like on some CD decks when music is playing. Instead, the outer edge of the dial is illuminated to simulate a moving platter, and you have the choice of six different light patterns. You can also personalise the jog dial by removing the transparent plastic top plate (using the supplied mini-screwdriver) and replacing the standard jog sheet with a design of your own.
Despite a plasticky finish and a lightweight feel, the CDJ-400 is put together well and should stand up to a fair amount of abuse by overzealous DJs. My main criticism with the design is the top-mounted USB port. Plug in a USB key and not only does it ruin the CDJ-400's sleek looks, but it's also just waiting to get snared up in cables or knocked and damaged. I would have preferred a rear-mounted USB port located close to the unit's top edge for easy access.
Situated directly above the jog dial are buttons to control the various digital loop functions. One neat feature is the Beat Loop/Loop Divide function, which automatically creates a four beat loop based on the Beats Per Minute (BPM) of the current track. A further press of the ‘-‘ button will divide the current loop, and pressing the ‘+' button returns the loop to the original length. Naturally, you can still create your own loops manually using the separate IN and OUT buttons. The CDJ-400 will also store one cue or loop point in memory for each track, which can also be copied to another CDJ-400 via a USB memory device.