Performance Optimized Down Fire Wide Sealed 10" Enclosure Hertz Mille Pro MPS 250 · Single 10" Sealed enclosure

Because it is only 12 inches deep. The standard Performance Optimized Down Fire platform is 30 wide by 15 deep, and this application needs a cabinet that fits a space three inches shallower than that.

The airspace has to come from somewhere, so the cabinet runs 41 inches long instead of 30 and stands 4.8125 inches tall. If you have 15 inches of depth, the standard cabinet is the pick; if your space is long and shallow, under a rear bench or on a narrow cargo floor, this is the shape that fits.

The standard cabinet is 30 x 15 x 4.9375 inches and holds 0.549 cubic feet net. This cabinet is 41 x 12 x 4.8125 and holds 0.572 cubic feet net, within 0.023 cubic feet of the standard box. Acoustically they are effectively the same enclosure. The choice is about shape: the standard box needs 15 inches of depth, this one needs 12 inches of depth and 41 inches of run.

The 3.25 inch mounting depth sets the cabinet height, which lands the airspace a little above Hertz's 14.2 liter recommendation. At 0.572 cubic feet net: MPS 250 S2: Qtc 0.650, Fc 44.4 Hz, F3 48.6 Hz. MPS 250 S4: Qtc 0.729, Fc 44.1 Hz, F3 42.8 Hz. The S2 is the tighter alignment and the S4 reaches lower.

Those are anechoic figures. Firing into the floor, the sealed rolloff meets rising cabin gain, so in-car response runs deeper than the numbers above.

On this size the S2 is the better damped driver, Qts 0.41 against the S4's 0.48, and the S4 reaches lower with more motor force, 17.3 T·m against 14.7. Both 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 decide on character; the pattern reverses on the 12 inch MPS 300.

The MPS 250 is single voice coil, so there is no coil wiring decision. Your impedance is set by the model you buy. Hertz measures its dual coil models in parallel and notes that Fs, Vas and Qts are the same in series, with only Re, Le and BL changing.

Side mounted. Every Proline X Performance Optimized enclosure uses a side mounted terminal cup, and on a down fire cabinet that keeps the connection accessible with the enclosure installed, 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, with no radii.

The front baffle is a double layer at 1.5 inches, with the outer layer machined as a flush recess so the driver bolts to the inner layer. A windowed U-brace ties the long panels together across the 41 inch span. Polyfill is installed as a light wall lining. Assembled and inspected in Tullahoma, Tennessee.

No. This listing is for the enclosure only. Bring your own Hertz Mille Pro MPS 250 S2 or MPS 250 S4. The cutout and mounting depth are direct fit for either version.