DD Audio 9921a D0.5

Features:
The 9900 Series woofers were developed in response to the low frequency explosion in music, across all genres. These subwoofers were designed to provide long term power handling, with accuracy, and ultra-long excursion.

The 9900 motor is a beast, with 3 inches of magnet cross section area, a diameter over 10 inches, and weighs in at 70 pounds. The traditionally tight DD magnet gap drives long throw flat aluminum voice coils to a peak excursion in excess of 3 inches, while keeping enough turns in the magnetic gap to maintain power and control.

The Beauty of the Beast

The 4” 9900 coils receive the same innovations developed for the Z Series coils, 5 layer former construction with double layer aluminum sidewalls, perimeter vents, double slit formers to reduce eddy currents and twice baked and coated for highest temperature resistance possible.

This high surface area coil (100% greater than a 9500 voice coil) is immersed in the extensively CnC machined, DD Free FLow Cooling System motor design - perimeter basket vents - vertical top plate vents - horizontal and vertical pole vents - vertical back plate vents - the harder the speaker is driven, the more air is pumped around through the voice coil.

The magnet gap uses a symmetric flux topology with a pole piece that is flush with the top plate, and undercut below the magnetic gap. Fixed to the top of the pole piece is a black anodized aluminum ring that does double duty as Faraday Ring and high efficiency heat sink.

The technology tour de force focus continues with the rest of the moving parts. The composite, multi-spider assembly is comprised of 5 layers consisting of 3 different materials heat formed into a linear, long wearing suspension designed to give years of service. The X-11 cone is made from the strongest synthetic pulp known to man and is non-pressed to expand the cross section area for increased rigidity. The 2 layer EROM surround maximizes cone area and travel while reducing moving mass.

For additional endurance we take a page from our competition SPL playbook and arm the 9900 with a reinforced triple joint. We do this by strengthening the former wall with a layer of fiberglass, and then we rope the coil which adds additional surface area to the glue beads above and below the spider.

The 9900 is the go to subwoofer for the demanding bassaholic with a profound interest in physics. Entertaining minds will revel in the endless system design possibilities deliverable with these precision low frequency devices.