Performance Optimized Down Fire Sealed 10" Enclosure | Diamond Audio DMD-SH Single 10" Sealed enclosure

Because the alignment is better. Diamond suggests 0.45 cubic feet, which computes to roughly Qtc 0.98 on the DMD102SH and above 1.14 on the DMD104SH - both underdamped with a pronounced lift near the corner frequency. At 0.80 cubic feet net the D2 lands at Qtc 1.003 and the D4 at 0.981, with 2 to 3 Hz more low-end extension on both. Diamond's own manual describes their enclosure table as a suggestion rather than a specification, and the extra volume costs about an inch of cabinet height.

Because Diamond's enclosure table does not reconcile with the Thiele-Small parameters printed on the same page. Their table lists the DMD102SH at Qtc 0.78 in 0.45 cubic feet. Running their own published Qts of 0.66 and Vas of 15.4 liters through standard sealed box math at that volume produces 0.98 instead. Every variant is off in the same direction by roughly 0.2 to 0.3.

This is not a gross versus net volume convention issue, which some manufacturers do have. No reasonable interpretation of the volume closes a gap that large. We publish figures computed directly from the driver parameters, because those are what the driver will actually do in this enclosure.

These two differ more than most dual-impedance pairs. The DMD102SH runs a Qts of 0.66 with 13.7 T of motor force and 7.9mm of Xmax, landing at Qtc 1.003 in this cabinet. The DMD104SH runs a Qts of 0.77 with 16.4 T and 8.8mm, landing at Qtc 0.981. So the D4 has the stronger motor and more excursion capability while the D2 has noticeably better damping. Check what load your amplifier is stable into first. If either works, choose the D2 for accuracy and control, the D4 for output.

Because the driver's free-air resonance is 48 Hz, which is high. A sealed enclosure raises the system corner frequency above the driver's Fs, so no sealed box puts this driver into the 30s. The DMD-SH is designed for punch and midbass authority from a 3 inch mounting depth rather than for deep extension. In a vehicle, cabin gain rising below 50 Hz fills in considerably below the anechoic figure, so in-car response is meaningfully better than the number suggests.

Side mounted. Every Proline X Performance Optimized enclosure uses a side mounted terminal cup regardless of alignment, whether standard, wedge, or down fire. On this cabinet that keeps the connection fully accessible with the enclosure in its installed position, since the baffle faces the floor. The cup is our Proline X ABS and carbon fiber composite unit, recessed, with stainless hardware, copper ring terminals, and pre-wired 12 gauge OFC.

Down Fire cabinets are built with square corners as a series standard. The 3 inch top down corner radius used on other Proline X alignments does not apply here. A down fire box is a low, wide platform that sits flat against a floor or under a seat, and square corners maximize usable internal volume for a given footprint while keeping the cabinet stable on its mounting surface.

V-groove and dado joinery, CNC-cut on ShopSabre routers from Langboard Elite MDF. Every panel joint is a machined interlocking groove that mechanically locks the panels before adhesive is applied, which is what keeps the cabinet airtight under sustained pressure cycling. The front baffle is a double layer at 1.5 inches, two bonded 3/4 inch sheets, standard across the Performance Optimized Series. Perimeter cross-bracing and pre-installed polyfill complete the build. Assembled and inspected in Tullahoma, Tennessee.

No. This listing is for the enclosure only. Bring your own Diamond Audio DMD102SH or DMD104SH. The cutout and mounting depth are direct fit for either version.