{"product_id":"performance-optimized-down-fire-sealed-12-enclosure-hertz-mille-pro-mp-300","title":"Performance Optimized Down Fire Sealed 12\" Enclosure | Hertz Mille Pro MP 300","description":"\u003cstyle\u003e.df-wrap{font-family:'Helvetica Neue',Arial,sans-serif;line-height:1.75;color:#d6d3d1;max-width:1100px;margin:0 auto;background:#0c0a09}.df-wrap *{box-sizing:border-box}.df-hero{background:linear-gradient(135deg,#0c0a09 0%,#5c3317 100%);padding:54px 36px;text-align:center;color:#fff}.df-hero h2{font-size:2.3em;font-weight:800;text-transform:uppercase;letter-spacing:1.5px;margin:0 0 12px;color:#fff}.df-hero p{font-size:1.1em;font-weight:300;opacity:.93;margin:0 0 22px;color:#d6d3d1}.df-badges{display:flex;justify-content:center;flex-wrap:wrap;gap:10px}.df-badge{background:rgba(184,115,51,.18);border:1px solid #b87333;color:#e8b98d;padding:7px 16px;border-radius:18px;font-size:.8em;font-weight:600}.df-stats{display:flex;flex-wrap:wrap;background:#1c1917}.df-stat{flex:1 1 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class=\"df-wrap\"\u003e\n\u003cdiv class=\"df-hero\"\u003e\n\u003ch2\u003eProline X Performance Optimized Down Fire 12\" Sealed\u003c\/h2\u003e\n\u003cp\u003eCut and tuned for the Hertz Mille Pro MP 300\u003c\/p\u003e\n\u003cdiv class=\"df-badges\"\u003e\n\u003cspan class=\"df-badge\"\u003eV-Groove and Dado\u003c\/span\u003e\u003cspan class=\"df-badge\"\u003eLangboard Elite MDF\u003c\/span\u003e\u003cspan class=\"df-badge\"\u003e1.10 cu ft Net\u003c\/span\u003e\u003cspan class=\"df-badge\"\u003e86 dB Sensitivity\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-stats\"\u003e\n\u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e1.10\u003c\/span\u003e\u003cspan class=\"l\"\u003ecu ft net\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e0.771\u003c\/span\u003e\u003cspan class=\"l\"\u003esystem Qtc\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e40.7 Hz\u003c\/span\u003e\u003cspan class=\"l\"\u003eF3 rolloff\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e8.125 in\u003c\/span\u003e\u003cspan class=\"l\"\u003ecabinet height\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003ePerformance, Performance Optimized, and Micro\u003c\/h3\u003e\n\u003cp\u003eProline X builds three tiers of Down Fire enclosure. The difference is not finish or materials, it is whether the cabinet was designed for a category or for a driver, and how much of the fitting work is already done for you.\u003c\/p\u003e\n\u003cdiv class=\"df-tier\"\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003e \u003c\/th\u003e\n\u003cth\u003ePerformance\u003c\/th\u003e\n\u003cth class=\"on\"\u003ePerformance Optimized\u003c\/th\u003e\n\u003cth\u003eMicro Series\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd class=\"a\"\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eUniversal. Accepts any subwoofer that clears the published cutout and mounting depth.\u003c\/td\u003e\n\u003ctd class=\"on\"\u003eWoofer specific. Cut for one named subwoofer, with cutout, mounting depth, magnet clearance and displacement drawn in CAD from that driver.\u003c\/td\u003e\n\u003ctd\u003eWoofer specific. Cut for one named subwoofer.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd class=\"a\"\u003eFootprint\u003c\/td\u003e\n\u003ctd\u003eSized to the driver diameter. 24.5 by 13.5 inches on the 10 inch.\u003c\/td\u003e\n\u003ctd class=\"on\"\u003eShared 30 by 15 inch platform on most builds, with cabinet height as the variable. A few drivers need a wider or deeper platform.\u003c\/td\u003e\n\u003ctd\u003eCompact per driver footprint. 21.5 by 14.5 inches on the 10 inch.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd class=\"a\"\u003eFront baffle\u003c\/td\u003e\n\u003ctd\u003eSingle, 3\/4 inch.\u003c\/td\u003e\n\u003ctd class=\"on\"\u003eDouble, 1.5 inch, outer layer machined as a flush recess.\u003c\/td\u003e\n\u003ctd\u003eDouble, 1.5 inch.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd class=\"a\"\u003eDriver mounting\u003c\/td\u003e\n\u003ctd\u003eSolid flange. You drill your own mounting holes.\u003c\/td\u003e\n\u003ctd class=\"on\"\u003e8\/32 threaded inserts, stainless machine screws included.\u003c\/td\u003e\n\u003ctd\u003e8\/32 threaded inserts, stainless machine screws included.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd class=\"a\"\u003eJoinery\u003c\/td\u003e\n\u003ctd\u003eV-groove and dado, CNC cut.\u003c\/td\u003e\n\u003ctd class=\"on\"\u003eV-groove and dado, CNC cut, perimeter cross brace.\u003c\/td\u003e\n\u003ctd\u003eStack fab, dowel reinforced.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd class=\"a\"\u003ePublished alignment\u003c\/td\u003e\n\u003ctd\u003eModeled Qtc profiles across a range of drivers. No single response curve.\u003c\/td\u003e\n\u003ctd class=\"on\"\u003eA real predicted Qtc and F3 for that exact driver, calculated from its own Thiele-Small parameters.\u003c\/td\u003e\n\u003ctd\u003eTarget alignment described in the listing.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd class=\"a\"\u003eCarpet\u003c\/td\u003e\n\u003ctd\u003eGray standard, black optional.\u003c\/td\u003e\n\u003ctd class=\"on\"\u003ePlush black.\u003c\/td\u003e\n\u003ctd\u003ePlush black.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd class=\"a\"\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003e1 year limited.\u003c\/td\u003e\n\u003ctd class=\"on\"\u003e1 year limited.\u003c\/td\u003e\n\u003ctd\u003e2 years.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-note\"\u003e\u003cp\u003e\u003cstrong\u003eFeet ship with every tier, uninstalled on purpose.\u003c\/strong\u003e Mount them where your floor wants them for a down fire install, or leave them off and run the cabinet front firing or up firing. The orientation is yours to choose.\u003c\/p\u003e\u003c\/div\u003e\n\u003cdiv class=\"df-note\"\u003e\u003cp\u003e\u003cstrong\u003eThis page is a Performance Optimized enclosure.\u003c\/strong\u003e The airspace, the cutout and the cabinet height all come from the Hertz Mille Pro MP 300's own published numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003eBuilt Around the Hertz MP 300\u003c\/h3\u003e\n\u003cp\u003eNothing about this cabinet is generic. The baffle is bored to the MP 300's \u003cstrong\u003e287mm cutout\u003c\/strong\u003e, 11.30 inches, and the internal height is set by its \u003cstrong\u003e6.46 inch mounting depth\u003c\/strong\u003e. The driver bolts to 8\/32 threaded inserts with stainless machine screws included, and at 8.63 kg it is a heavy motor that wants a baffle it can actually pull against.\u003c\/p\u003e\n\u003cp\u003eThe driver underneath is a genuinely capable foundation for a sealed 12: a \u003cstrong\u003e24 Hz free-air resonance\u003c\/strong\u003e, 74 liters of Vas, and a Qts of 0.42 that is low enough to reach a properly damped sealed alignment. Effective cone diameter is 260mm.\u003c\/p\u003e\n\u003cp\u003eThe construction is classic Hertz. The cone is a \u003cstrong\u003eV-cone profile\u003c\/strong\u003e pressed from paper pulp with mineral powder injection, the same technique used on the flagship Mille Legend line, so the diaphragm behaves like a piston rather than flexing at the edge under load. The surround is high-purity IIR butyl rubber. A \u003cstrong\u003e65mm four-layer CCAW voice coil\u003c\/strong\u003e sits on a vented TIL-P former, driven by a compact high-density ferrite motor with a BL of 12 T\/m, all carried in a six-spoke aluminum alloy basket vented under the spider. Excursion is 17mm linear with 27mm of mechanical travel before damage.\u003c\/p\u003e\n\u003cp\u003eOne clarification if you are cross shopping our Hertz cabinets: the Mille Pro MPS series is the shallower line and gets its own cabinets. This page is cut for the Mille Pro MP 300 only.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003eNet Volume, Not Gross\u003c\/h3\u003e\n\u003cp\u003eWe build this cabinet at \u003cstrong\u003e1.10 cubic feet net\u003c\/strong\u003e against 1.26 gross. Hertz publishes 28 liters, or 0.99 cubic feet, as the recommended sealed volume, and this cabinet runs slightly larger because the driver's 6.46 inch mounting depth sets the floor on internal height. With the flush recess outer baffle layer and a milled magnet relief both recovering clearance, the minimum internal height still works out to 5.875 inches.\u003c\/p\u003e\n\u003cdiv class=\"df-highlight\"\u003e\u003cp\u003e\u003cstrong\u003eTrue net, not marketing net.\u003c\/strong\u003e Internal volume is calculated from the machined cavity dimensions and the driver's published displacement, not estimated from external dimensions minus wall thickness.\u003c\/p\u003e\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eThe extra volume lands in your favor.\u003c\/strong\u003e Computed from Hertz's published Fs of 24 Hz, Qts of 0.42 and Vas of 74 liters, this cabinet reaches \u003cstrong\u003eQtc 0.771 with Fc at 44.1 Hz and a predicted F3 of 40.7 Hz\u003c\/strong\u003e. Hertz publishes Qtc 0.82 and Fb 48 Hz at their own 28 liter figure. Better damped, gentler corner, no meaningful loss anywhere.\u003c\/p\u003e\n\u003cp\u003eWorth saying plainly: Hertz's published enclosure data reconciles with their own Thiele-Small parameters, which is less common in this category than it should be. Running their numbers independently at their own 28 liters produces Qtc 0.80 against a published 0.82.\u003c\/p\u003e\n\u003cp\u003eThe \u003cstrong\u003eMP 300 D2.3\u003c\/strong\u003e and \u003cstrong\u003eMP 300 D4.3\u003c\/strong\u003e share the same Thiele-Small set, so the alignment above applies to both. The difference is coil impedance, which you set at the driver, not a difference in enclosure behavior.\u003c\/p\u003e\n\u003cp\u003eFiring down into the floor, the sealed rolloff meets rising cabin gain below 60 Hz, so in-car response extends below the anechoic figure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003eDown Fire Construction\u003c\/h3\u003e\n\u003cp\u003eCut with V-groove and dado joinery on our ShopSabre routers from Langboard Elite 3\/4 inch MDF. Every panel joint is a machined interlocking groove that mechanically locks before adhesive is applied, which keeps the cabinet airtight under sustained pressure cycling. Perimeter cross-bracing ties the panels together and polyfill is pre-installed. Corners are square on Down Fire cabinets.\u003c\/p\u003e\n\u003cp\u003eExternal dimensions are \u003cstrong\u003e30 inches wide by 15 inches deep by 8.125 inches tall, measured in the down fire position\u003c\/strong\u003e. The driver fires down into the floor, and the finished weight is 34 pounds.\u003c\/p\u003e\n\u003cdiv class=\"df-grid\"\u003e\n\u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eDouble Baffle, Flush Recess\u003c\/h4\u003e\n\u003cp\u003eThe front baffle is \u003cstrong\u003e1.5 inches\u003c\/strong\u003e, two bonded 3\/4 inch sheets, with the outer layer machined as a flush recess so the driver bolts to the inner layer. That recovers 3\/4 inch of internal clearance, which matters with an 11.30 inch cutout.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eSide-Mounted Terminal Cup\u003c\/h4\u003e\n\u003cp\u003eProline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, pre-wired in \u003cstrong\u003e12 gauge OFC\u003c\/strong\u003e. Side mounted so it stays accessible with the baffle facing the floor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eMilled Magnet Relief\u003c\/h4\u003e\n\u003cp\u003eA \u003cstrong\u003e3\/8 inch deep relief\u003c\/strong\u003e is machined into the panel opposite the baffle, directly behind the magnet, so the MP 300's motor gets its clearance without adding cabinet height.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- ENCLOSURE PERFORMANCE SLOT --\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003ePower and Warranty\u003c\/h3\u003e\n\u003cp\u003eHertz rates the MP 300 at \u003cstrong\u003e600 watts RMS and 1200 watts peak\u003c\/strong\u003e, and sensitivity is \u003cstrong\u003e86 dB at 1W\/1m\u003c\/strong\u003e, among the most efficient drivers in the Down Fire line. Most subwoofers in this category sit in the low to mid 80s, so the MP 300 reaches a given output on less amplifier power, which also reduces thermal stress over long sessions.\u003c\/p\u003e\n\u003cp\u003eBoth versions are dual voice coil, so final impedance is set at the driver: the D2.3 gives 1 ohm in parallel or 4 ohms in series, the D4.3 gives 2 ohms in parallel or 8 in series. Confirm your amplifier is stable at your chosen load before powering the system.\u003c\/p\u003e\n\u003cp\u003eThe enclosure carries a 1 year limited warranty. Bring your own Hertz Mille Pro MP 300 D2.3 or MP 300 D4.3; the driver is purchased separately. The cutout, mounting depth and magnet clearance are all cut for that driver specifically.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-cta\"\u003e\n\u003ch3\u003eCut for the Driver, Not the Catalog\u003c\/h3\u003e\n\u003cp\u003eOne driver, one set of published parameters, one cabinet machined to match them. Built one at a time in Tullahoma, Tennessee.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n","brand":"Proline X","offers":[{"title":"Default Title","offer_id":44540886548569,"sku":"PO 12-S DF MP","price":269.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0689\/1389\/files\/PO12-SDFMPFaceDown.jpg?v=1787384600","url":"https:\/\/audiointensity.com\/products\/performance-optimized-down-fire-sealed-12-enclosure-hertz-mille-pro-mp-300","provider":"Audio Intensity","version":"1.0","type":"link"}