{"product_id":"performance-optimized-down-fire-wide-sealed-dual-12-enclosure-powerbass-xl-1240t","title":"Performance Optimized Down Fire Wide Sealed Dual 12\" Enclosure | PowerBass XL-1240T","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 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td.on{background:rgba(184,115,51,.10);color:#d6d3d1}.df-tier tr:last-child td{border-bottom:none}@media(max-width:600px){.df-hero h2{font-size:1.7em}.df-section,.df-enc,.df-cta,.df-hero{padding-left:20px;padding-right:20px}}\u003c\/style\u003e\n\u003cdiv class=\"df-wrap\"\u003e\n\u003cdiv class=\"df-hero\"\u003e\n\u003ch2\u003eProline X Performance Optimized Down Fire Wide Dual 12\" Sealed\u003c\/h2\u003e\n\u003cp\u003e41 by 14 inch footprint for spaces where height or depth is the limit. Cut for a pair of PowerBass XL-1240T subwoofers\u003c\/p\u003e\n\u003cdiv class=\"df-badges\"\u003e\n\u003cspan class=\"df-badge\"\u003eDown Fire Wide\u003c\/span\u003e\u003cspan class=\"df-badge\"\u003eV-Groove and Dado\u003c\/span\u003e\u003cspan class=\"df-badge\"\u003e14\" Deep\u003c\/span\u003e\u003cspan class=\"df-badge\"\u003eSeparate Chambers\u003c\/span\u003e\u003cspan class=\"df-badge\"\u003eStandoffs Included\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\"\u003e0.403\u003c\/span\u003e\u003cspan class=\"l\"\u003ecu ft net each\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e1.142\u003c\/span\u003e\u003cspan class=\"l\"\u003esystem Qtc, per chamber\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e53.5 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\"\u003e6.125 in\u003c\/span\u003e\u003cspan class=\"l\"\u003ecabinet height, excludes standoffs\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003eThe Down Fire Wide Format\u003c\/h3\u003e\n\u003cp\u003eDown Fire Wide takes the same pair of PowerBass XL-1240T our standard 30 by 15 inch Down Fire enclosure is built for and lays the cabinet out along a different axis. It is \u003cstrong\u003e1 inch shallower front to back\u003c\/strong\u003e, 14 inches instead of 15, and \u003cstrong\u003e11 inches longer\u003c\/strong\u003e, 41 instead of 30.\u003c\/p\u003e\n\u003cp\u003eFourteen inches is the practical minimum depth for a 12. The frame needs about 13 inches of baffle, and the cabinet walls need land around it, so the depth cannot come down further. The XL-1240T's 12.244 inch frame sits on the 14 inch deep baffle with about 0.88 inch of baffle fore and aft.\u003c\/p\u003e\n\u003cp\u003eSpreading the airspace along 41 inches means the wide box stands lower. This cabinet is \u003cstrong\u003e41 inches wide by 14 inches deep by 6.125 inches tall\u003c\/strong\u003e, against 7.28 inches tall for the standard 30 by 15, both measured in the down fire position and excluding standoffs. With the 1.75 inch standoffs installed it stands 7.875 inches.\u003c\/p\u003e\n\u003cdiv class=\"df-highlight\"\u003e\n\u003cp\u003e\u003cstrong\u003eWhich one to choose.\u003c\/strong\u003e The standard 30 by 15 is the pick when length is limited. This one is the pick when height or depth is the limit and you have 41 inches of run. Measure all three before ordering.\u003c\/p\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. Down Fire Wide variants like this one run 41 by 14 for spaces where height or depth is the limit.\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 layer, outer layer machined as a flush recess. 1.5 inch.\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 cutout, the cabinet height and the airspace all come from the PowerBass XL-1240T'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 PowerBass XL-1240T\u003c\/h3\u003e\n\u003cp\u003eThe baffle positions are bored direct fit to the XL-1240T's published cutout. This is a shallow mount driver: \u003cstrong\u003e3.8 inch mounting depth\u003c\/strong\u003e, 7.5 mm of one-way excursion on a 2 in voice coil, \u003cstrong\u003e400 watts RMS and 800 peak\u003c\/strong\u003e, rated 33 Hz to 450 Hz.\u003c\/p\u003e\n\u003cp\u003ePublished parameters are Fs 33 Hz, Qts 0.526 and Vas 42.37 litres, with 0.126 cubic feet of driver displacement. PowerBass names 0.40 as the optimum sealed volume, quoted as internal airspace that includes the driver's displacement, lists 0.30 to 0.85 as the acceptable range, and does not recommend a ported enclosure for this driver at all.\u003c\/p\u003e\n\u003cp\u003eThe XL-T uses a \u003cstrong\u003evented rear motor\u003c\/strong\u003e, so the pole vent can be obstructed without harming the driver. On a down fire cabinet that matters: the motor sits inside the enclosure firing at the top panel, and a driver that needs its pole vent kept clear forces a taller box.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003eNet Volume, Not Gross\u003c\/h3\u003e\n\u003cp\u003eEach chamber holds \u003cstrong\u003e0.403 cubic feet net\u003c\/strong\u003e, 0.806 cubic feet net total from a 1.08 cubic foot gross cavity, after the divider, the brace work and each driver's 0.126 cubic feet of displacement are subtracted.\u003c\/p\u003e\n\u003cp\u003eThat produces \u003cstrong\u003eQtc 1.142 with Fc at 71.6 Hz and a predicted F3 of 53.5 Hz per driver\u003c\/strong\u003e. The figure is above the 0.707 maximally flat reference, so there is real lift near the corner rather than a textbook flat curve.\u003c\/p\u003e\n\u003cp\u003ePowerBass quotes its 0.40 recommendation as gross airspace that includes the driver. Each chamber here is 0.403 net, so it sits slightly on the larger side of their optimum and well inside the range they list as acceptable. This is a deliberately small-box alignment with real lift at resonance: tight rather than deep.\u003c\/p\u003e\n\u003cp\u003eTrue net, not marketing net. Internal volume is calculated from the machined cavity dimensions and the driver's published displacement, not estimated from external dimensions minus wall thickness. All figures are anechoic; firing down into the floor, the sealed rolloff meets rising cabin gain below 60 Hz, so in-car response extends below them.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003eTwo Chambers, Not One\u003c\/h3\u003e\n\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.\u003c\/p\u003e\n\u003cp\u003eTwo drivers sharing one sealed volume interact acoustically. Each driver's compression phase becomes the pressure environment the other is working against, which smears transient response and blurs the alignment each would have on its own. A full divider eliminates that. Each driver gets its own 0.403 cubic feet net and its own polyfill, and one shared side mounted terminal cup feeds both positions.\u003c\/p\u003e\n\u003cp\u003eOn a long cabinet the divider does structural work as well, tying the front and rear walls together at the centre of a 41 inch span.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003eDown Fire Wide Construction\u003c\/h3\u003e\n\u003cp\u003eCut with V-groove and dado joinery on our ShopSabre routers from Langboard Elite 3\/4 inch MDF, a dense 48.5 lb\/ft³ board with a 200 psi internal bond and 410,000 psi MOE. Every panel joint is a machined interlocking groove that mechanically locks before adhesive is applied, which keeps both chambers airtight under sustained pressure cycling. Corners are square on Down Fire cabinets.\u003c\/p\u003e\n\u003cp\u003eThe cabinet measures \u003cstrong\u003e41 inches wide by 14 inches deep by 6.125 inches tall, measured in the down fire position and excluding standoffs\u003c\/strong\u003e. The 1.75 inch standoffs ship with the enclosure but are not installed, so plan the space around the installed height of 7.875 inches.\u003c\/p\u003e\n\u003cdiv class=\"df-grid\"\u003e\n\u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003e1.5 Inch Double Baffle\u003c\/h4\u003e\n\u003cp\u003eTwo \u003cstrong\u003e3\/4 inch layers laminated to 1.5 inches\u003c\/strong\u003e, with the outer layer machined as a flush recess so the driver bolts to the inner layer. Mounting is threaded inserts with stainless machine screws.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eFrame on a 14 Inch Baffle\u003c\/h4\u003e\n\u003cp\u003eThe 12.244 inch frame sits on the \u003cstrong\u003e14 inch deep baffle\u003c\/strong\u003e with about 0.88 inch of material fore and aft.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eSeparate Chambers\u003c\/h4\u003e\n\u003cp\u003eA bonded \u003cstrong\u003efull-height 3\/4 inch divider\u003c\/strong\u003e gives each driver its own 0.403 cubic feet and its own polyfill, and ties the walls together mid span.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eOne Shared Terminal Cup\u003c\/h4\u003e\n\u003cp\u003eProline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, \u003cstrong\u003eside mounted\u003c\/strong\u003e and pre-wired in 12 gauge OFC to both driver positions in parallel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eStandoffs and Polyfill\u003c\/h4\u003e\n\u003cp\u003e\u003cstrong\u003e1.75 inch standoffs\u003c\/strong\u003e ship uninstalled, so you can place them to suit your floor or leave them off and run the cabinet front or up firing. Polyfill is installed as a light wall lining in each chamber and does not alter the acoustic volume.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"df-section\"\u003e\n\u003ch3\u003ePower and Wiring\u003c\/h3\u003e\n\u003cp\u003eEach XL-1240T is a single 4 ohm voice coil rated \u003cstrong\u003e400 watts RMS\u003c\/strong\u003e, 800 watts RMS combined across the pair. The shared cup feeds both positions in parallel, so the pair presents 2 ohms at the cup. Target 400 watts RMS per driver and set gains properly rather than to a number.\u003c\/p\u003e\n\u003cp\u003eThe enclosure carries a 1 year limited warranty. Bring your own pair of XL-1240T drivers; they are purchased separately. We do not stock PowerBass drivers.\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\u003eDown Fire Wide, 41 by 14, cut on our ShopSabre routers and built one at a time in Tullahoma, Tennessee. Questions on fitment or amplifier matching, call us at 931-563-5151.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":47345339039833,"sku":"PO 12D-S DFW XLT","price":329.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0689\/1389\/files\/PO_12D_S_DFW_XLT_Front.jpg?v=1790650501","url":"https:\/\/audiointensity.com\/products\/performance-optimized-down-fire-wide-sealed-dual-12-enclosure-powerbass-xl-1240t","provider":"Audio Intensity","version":"1.0","type":"link"}