DD Audio SL612-D2

The SL600 series subwoofers, which include the DD Audio HI-DEF SL612 12" (30cm) flat subwoofer, feature a very shallow mounting depth, and the suspensions have been tuned to perform exceptionally well in sealed and small bass-reflex enclosures.
To ensure high power handling, good cooling and large excursion, the SL600 subwoofers feature 2.5-inch high-temperature voice coils, 72-ounce magnets, rear panel coil venting and an EROM surround.
One of the unique features of the SL600 is the three-layer, low-profile diaphragm cone. By compressing a layer of foam between two layers of cellulose, the cone is as light and stiff as a standard cone, yet flat enough to allow a suspension travel equivalent to that of a full-sized subwoofer.