X-6.5 v.2 S4

The X-6.5SW is the first true subwoofer under 8 inches in the Sundown lineup, rated 400W RMS on a single 4-ohm voice coil. It uses a coil with the same winding dimensions as the SA-8 v.3: a 2" diameter with a 1.4" winding height, which is why thermal power handling is so high for a woofer this small. Xmax is 16mm one-way measured at 70 percent BL.

The coil is a 4-layer CCAW winding on a thick Kapton former, and a copper pole cap reduces inductive distortion for cleaner output. A large noise-free pole vent and a spiral-cut basket venting pattern unique to this model keep air moving through the motor. The diaphragm is a proprietary flat aluminum design, and integrated tinsel leads stop lead slapping at high excursion.

Read this part before you build: the X-6.5SW is mechanically limited and needs a small ported enclosure. Recommended volume is 0.25 to 0.33 cu ft, with 0.3 cu ft, 4 sq in of port area, and 32Hz tuning as the target. A large box or a sealed box cuts mechanical power handling substantially, so a 0.15 cu ft sealed enclosure is the only sealed option and it trades output for space.

Physically it is small enough to open up places a larger woofer cannot go: 4.00" mounting depth, a 6.75" outside diameter, a 5.52" cutout, and 0.05 cu ft of displacement. That makes it workable in door builds, motorcycle and side-by-side enclosures, under-seat boxes, and compact car bass systems that still need real low frequency output.