Performance Optimized Down Fire Sealed Dual 10" Enclosure | Hertz Mille Pro MPS 250 Dual 10" Sealed enclosure

Because two drivers in a shared sealed volume interact acoustically. Each driver's compression phase becomes the pressure environment the other driver is working against, which smears transient response and blurs the alignment each would have on its own. A full-height bonded 3/4 inch MDF divider eliminates that completely. Each MPS 250 gets its own 0.50 cubic feet net, matching Hertz's own recommendation, plus its own polyfill. Separate chambers are the standing design rule on every Proline X dual sealed enclosure.

Acoustically identical per driver, roughly 6 dB more maximum output. Both give each MPS 250 exactly 0.50 cubic feet net and land at Qtc 0.759 on the S2 or 0.754 on the S4. The difference is physical: both share the 30 by 15 inch footprint, but the single stands 4.9375 inches tall and the dual stands 7.6875. Combined power handling doubles to 1000 watts RMS. The single fits under seats; the dual is a cargo floor or rear-wall build.

On this size the S2 is the better damped driver, with a free-air Qts of 0.41 against the S4's 0.48, landing at Qtc 0.759 per chamber versus 0.754. The S4 reaches slightly lower and carries more motor force.

Whichever you choose, use two of the same model. Mismatched drivers between the two chambers will not track each other and the pair will not behave predictably. Note also that this damping pattern reverses on the 12 inch MPS 300, where the S4 is the tighter driver. Both models are single voice coil, so your final load depends on the model and how the pair is wired at the amplifier.

The enclosure uses one side-mounted Proline X terminal cup with a single pair of posts, pre-wired in 12 gauge OFC to both driver positions in parallel. You do not wire the two chambers separately at the amplifier.

Both MPS 250 models are single voice coil, so there is no coil configuration decision at the driver. Your final load is determined by which model you install - 2 ohms each for the S2, 4 ohms each for the S4 - and how that pair resolves through the cup. Confirm the resulting impedance against your amplifier's minimum stable load before powering the system.

Side mounted, and there is one cup serving both chambers rather than one per chamber. 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 both baffles face 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 cargo deck, 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 both chambers airtight under sustained pressure cycling. The chamber divider is a full-height bonded 3/4 inch panel. Front baffles are double-layer at 1.5 inches, two bonded 3/4 inch sheets, at both driver positions. Perimeter cross-bracing and pre-installed polyfill in each chamber complete the build. Assembled and inspected in Tullahoma, Tennessee.

No. This listing is for the enclosure only. Bring your own pair of Hertz Mille Pro MPS 250 S2 or MPS 250 S4 subwoofers. The cutouts and mounting depth are direct fit at both driver positions for either version. Use two of the same model.