Performance Optimized Down Fire Wide Sealed 12" Enclosure Hertz Mille Pro MPS 300 · Single 12" Sealed enclosure

Because some installs run out of height or depth before they run out of length. The standard Hertz Mille Pro MPS 300 Down Fire cabinet is 30 by 15 by 6.375 inches; this one is 41 by 14 by 5.3125. Spreading the airspace along 11 more inches lets the cabinet stand 1.0625 inches lower, and at 14 inches deep it is 1 inch shallower front to back, about the minimum a 12 inch frame needs.

If you have 41 inches of run and height or depth is the limit, this is the shape. If length is the limit, the standard 30 x 15 is the better fit.

Same driver, same construction, different shape. The standard box is 30 by 15 by 6.375 inches and holds 0.846 cubic feet net; this one is 41 by 14 by 5.3125 inches and holds 0.814 cubic feet net.

The airspaces are within 0.032 cubic feet, so the alignment is effectively the same: Qtc 0.996 against 0.982 on the S2, 0.807 against 0.796 on the S4. The choice is about the shape of your space: the standard box when length is limited, this one when height or depth is the limit and you have 41 inches of run.

On this size the S4 is the better damped driver, with a free-air Qts of 0.42 against the S2's 0.51. In this cabinet the S4 lands at Qtc 0.807 with F3 at 39.4 Hz and the S2 at Qtc 0.996 with F3 at 36.9 Hz.

This is the opposite of the 10 inch MPS 250. Both models are single voice coil, so impedance is fixed by the model: 2 ohms for the S2, 4 ohms for the S4. Check your amplifier first, then choose the S4 for control or the S2 for extension.

Yes, and that is worth stating because it is not universal. Running Hertz's own published Qts and Vas through standard sealed box math at their recommended volume produces a corner frequency within a fraction of a hertz of the figure printed in their manual on both models. This cabinet holds 23.1 liters net, just over that recommended 22.7.

16.8mm one-way, exceptional for a shallow-mount driver. Combined with 500 watts RMS, a 3.465 inch mounting depth and a 24 Hz free-air resonance on the S2, the MPS 300 delivers real low frequency capability from a package thin enough for a cabinet 5.3125 inches tall.

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 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.

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 keeps the cabinet airtight under sustained pressure cycling. Corners are square, the Down Fire series standard.

The front baffle is a double layer at 1.5 inches, two bonded 3/4 inch sheets, with the outer layer machined as a flush recess so the driver bolts to the inner layer. A windowed U-brace ties the long 41 inch panels together and polyfill is installed as a light wall lining. That carries real structural load with an 11.14 inch cutout in a cabinet this shallow. Assembled and inspected in Tullahoma, Tennessee.

No. This listing is for the enclosure only. Bring your own Hertz Mille Pro MPS 300 S2 or MPS 300 S4. The cutout and mounting depth are direct fit for either version.