{"product_id":"performance-optimized-down-fire-sealed-dual-12-enclosure-hertz-mille-pro-mps-300","title":"Performance Optimized Down Fire Sealed Dual 12\" Enclosure | Hertz Mille Pro MPS 300","description":"\u003cp\u003eThe \u003cstrong\u003ePerformance Optimized Down Fire Sealed Dual 12\" Enclosure for the Hertz Mille Pro MPS 300\u003c\/strong\u003e is a two-chamber sealed cabinet built around a pair of Hertz shallow 12s. At \u003cstrong\u003e10.75 inches tall\u003c\/strong\u003e on a 30 by 15 inch footprint, it delivers roughly 6 dB more maximum output than a single driver in the same alignment.\u003c\/p\u003e\u003cp\u003eEach Hertz MPS 300 is available as the \u003cstrong\u003eMPS 300 S2\u003c\/strong\u003e (2Ω) or \u003cstrong\u003eMPS 300 S4\u003c\/strong\u003e (4Ω), rated 500 watts RMS and 1000 watts peak with a 3.46 inch mounting depth. Across the pair that is \u003cstrong\u003e1000 watts RMS combined\u003c\/strong\u003e. Each driver carries 16.8mm of Xmax, with a polypropylene cone, 38mm voice coil and high density flux ferrite motor.\u003c\/p\u003e\u003cp\u003eThis enclosure follows the Proline X standing design rule for dual sealed builds: \u003cstrong\u003etwo fully separate chambers\u003c\/strong\u003e divided by a bonded full-height 3\/4 inch MDF panel, giving each driver its own dedicated airspace. Two drivers sharing one sealed volume interact acoustically, with each driver's compression phase becoming the other's pressure environment, which smears transient response and blurs the alignment each would have on its own. Separate chambers eliminate that entirely.\u003c\/p\u003e\u003cp\u003eEach chamber gives \u003cstrong\u003e0.80 cubic feet net per driver\u003c\/strong\u003e, matching Hertz's own sealed recommendation of 22.7 liters. That produces \u003cstrong\u003eQtc 1.003 with F3 at 37.1 Hz on the S2\u003c\/strong\u003e, or \u003cstrong\u003eQtc 0.812 with F3 at 39.5 Hz on the S4\u003c\/strong\u003e, identical to the single-driver cabinet.\u003c\/p\u003e\u003cp\u003ePay attention to the coil choice, because \u003cstrong\u003eit reverses from the 10 inch model\u003c\/strong\u003e. On the MPS 300 the S4 is the better damped driver with a Qts of 0.42 against the S2's 0.51. On the MPS 250 it is the opposite. The S4 gives the more controlled alignment, the S2 reaches about 2.4 Hz lower. Whichever you choose, use two of the same model.\u003c\/p\u003e\u003cp\u003eAt 37.1 Hz on the S2 this is \u003cstrong\u003eamong the deepest-reaching enclosures in the Proline X Down Fire line\u003c\/strong\u003e, and it comes from a 24 Hz free-air resonance paired with a 64.9 liter Vas.\u003c\/p\u003e\u003cp\u003eHertz publishes Thiele-Small measured with coils in parallel and states Fs, Vas and Qts are identical in series wiring. One cabinet is correct for either configuration. Their published enclosure data also reconciles with their own T\/S parameters, which is not true of every manufacturer in this category.\u003c\/p\u003e\u003cp\u003eThis is the tallest cabinet in the Down Fire line at 10.75 inches. It is a cargo floor or rear-wall build rather than an under-seat one. Measure your vertical clearance before ordering.\u003c\/p\u003e\u003cp\u003eConstruction is the full Proline X Performance Optimized platform: ShopSabre CNC-cut Langboard Elite MDF with \u003cstrong\u003eV-groove and dado joinery\u003c\/strong\u003e, perimeter cross-bracing, and \u003cstrong\u003edouble-layer 1.5 inch front baffles\u003c\/strong\u003e (two 3\/4 inch sheets bonded) at both driver positions. Corners are square on Down Fire cabinets. Both drivers fire down into the floor, and \u003cstrong\u003eone side-mounted\u003c\/strong\u003e Proline X ABS\/carbon fiber composite terminal cup serves both chambers, fed in parallel to both driver positions with 12 gauge OFC.\u003c\/p\u003e\u003cp\u003eBring your own pair of MPS 300 S2 or MPS 300 S4. Both are single voice coil, so your final load is determined by which model you install and how the pair is wired at the amplifier.\u003c\/p\u003e\u003cp\u003eManufactured in Tullahoma, Tennessee. 1-year enclosure warranty.\u003c\/p\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":44540398174297,"sku":"PO 12D-S DF MPS","price":299.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0689\/1389\/files\/proline-x-micro-series-dual-15-sealed-enclosure-built-for-resonix-gus-15subwoofer-enclosuresproline-x-9360178_4188b18c-b0d1-464e-911e-6ad64cff1957.jpg?v=1787113028","url":"https:\/\/audiointensity.com\/products\/performance-optimized-down-fire-sealed-dual-12-enclosure-hertz-mille-pro-mps-300","provider":"Audio Intensity","version":"1.0","type":"link"}