{"title":"Fi Car Audio Subwoofer Boxes and Enclosures","description":"\u003cdiv class=\"ai-collection-block\"\u003e\n\n\u003ch2\u003eTwo Kinds of Fi Cabinet\u003c\/h2\u003e\n\n\u003cp\u003eFi Car Audio drivers split into two jobs on this page, and the cabinets follow.\u003c\/p\u003e\n\n\u003ch3\u003eAlpha, sealed wedges\u003c\/h3\u003e\n\u003cp\u003ePerformance Optimized sealed wedges for the Alpha 12 and Alpha 15, single and dual. Cut to one driver on a 1.5 inch double baffle and shipped with polyfill installed. The compact choice for a daily driver.\u003c\/p\u003e\n\n\u003ch3\u003eNEO and Xv4, ported for output\u003c\/h3\u003e\n\u003cp\u003eProfessional Series ported cabinets for the NEO 3.5 15, NEO 3.7 15 and Xv4 15, with dual versions for the NEO 3.5 and Xv4. These are larger cabinets for output, and they need the power to match. Tuning is stated on each listing.\u003c\/p\u003e\n\n\u003ch2\u003ePlan the Power and the Space\u003c\/h2\u003e\n\n\u003cp\u003eA 15 inch ported cabinet is a large box. Measure the opening with the trim in place and check the external dimensions on the product page before you order. Confirm your amplifier is stable at the final impedance your wiring produces, particularly on the dual cabinets.\u003c\/p\u003e\n\n\u003caside class=\"ai-callout-cta\"\u003e\n\u003cp class=\"ai-callout-label\"\u003eDifferent Fi Car Audio Driver?\u003c\/p\u003e\n\u003cp\u003eIf your model is not listed, tell us the driver and the space you have and we will tell you what we can build.\u003c\/p\u003e\n\u003cp\u003e\u003cspan class=\"ai-contact-phone\"\u003e931-563-5151\u003c\/span\u003e\u003cspan class=\"ai-contact-divider\"\u003e|\u003c\/span\u003e\u003cspan class=\"ai-contact-email\"\u003econtact@audiointensity.com\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/aside\u003e\n\n\u003ch2\u003eHow These Are Built\u003c\/h2\u003e\n\n\u003cp\u003eLangboard Elite MDF, CNC cut in Tullahoma, Tennessee, prewired to a Proline X ABS and carbon fiber terminal cup, and covered by a 2 year limited warranty on craftsmanship and materials.\u003c\/p\u003e\n\n\u003cp\u003eBrowse the wider range at the \u003ca href=\"https:\/\/audiointensity.com\/collections\/subwoofer-box\"\u003esubwoofer box hub\u003c\/a\u003e, or look at \u003ca href=\"https:\/\/audiointensity.com\/collections\/proline-x-performance-optimized-series\"\u003ePerformance Optimized enclosures\u003c\/a\u003e, \u003ca href=\"https:\/\/audiointensity.com\/collections\/proline-x-professional-series\"\u003eProfessional Series enclosures\u003c\/a\u003e and \u003ca href=\"https:\/\/audiointensity.com\/collections\/wedge-subwoofer-box\"\u003ewedge enclosures\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Fi Car Audio Enclosure Questions\u003c\/h2\u003e\n\n\u003ch3\u003eWhich Fi Car Audio subwoofers do these boxes fit?\u003c\/h3\u003e\n\u003cp\u003eThe Alpha 12, Alpha 15, NEO 3.5 15, NEO 3.7 15 and Xv4 15. Each listing names the exact driver it was cut for.\u003c\/p\u003e\n\n\u003ch3\u003eWhy are the Alpha boxes sealed and the NEO boxes ported?\u003c\/h3\u003e\n\u003cp\u003eThey are built for different jobs. The Alpha cabinets are compact sealed wedges for daily use. The NEO and Xv4 cabinets are Professional Series ported builds for output.\u003c\/p\u003e\n\n\u003ch3\u003eDo the sealed boxes come with polyfill?\u003c\/h3\u003e\n\u003cp\u003eYes. Every sealed cabinet ships with polyfill installed. The ported cabinets ship without it.\u003c\/p\u003e\n\n\u003ch3\u003eDo I need anything else to install one?\u003c\/h3\u003e\n\u003cp\u003eAn amplifier and wiring. These are passive enclosures with no amplification built in.\u003c\/p\u003e\n\n\u003c\/div\u003e","products":[{"product_id":"professional-series-ported-15-enclosure-fi-car-audio-xv4-15","title":"Professional Series Ported 15\" Enclosure | Fi Car Audio Xv4 15","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%,#001a91 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(91,120,255,.18);border:1px solid #5b78ff;color:#99abff;padding:7px 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p{margin:0;color:#d6d3d1;font-size:13.5px;line-height:1.6}.df-link{color:#7089ff;text-decoration:underline}.df-cta{background:linear-gradient(135deg,#0c0a09 0%,#001a91 100%);padding:40px 36px;text-align:center;color:#fff}.df-cta h3{color:#fff;font-size:1.4em;margin:0 0 10px;border:none;padding:0}.df-cta p{opacity:.92;margin:0 auto;max-width:640px;color:#d6d3d1}.df-tier{overflow-x:auto;margin:18px 0;border:1px solid #44403c;border-radius:8px}.df-tier table{width:100%;border-collapse:collapse;min-width:660px}.df-tier th{background:#0c0a09;color:#a8a29e;font-size:.74em;text-transform:uppercase;letter-spacing:.6px;padding:12px 14px;text-align:left;border-bottom:1px solid #44403c;font-weight:700}.df-tier th.on{background:#001264;color:#99abff}.df-tier td{padding:11px 14px;border-bottom:1px solid #292524;color:#a8a29e;font-size:.88em;vertical-align:top;line-height:1.55}.df-tier td.a{color:#d6d3d1;font-weight:700;background:#1c1917;width:19%}.df-tier td.on{background:rgba(91,120,255,.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\n\u003cdiv class=\"df-hero\"\u003e\n  \u003ch2\u003eProline X Professional 15\" Ported\u003c\/h2\u003e\n  \u003cp\u003eOne Xv4 15 in a front-firing box, vented at 34.5 Hz on a three-layer flush-mount baffle\u003c\/p\u003e\n  \u003cdiv class=\"df-badges\"\u003e\n    \u003cspan class=\"df-badge\"\u003e2.17 cu ft net\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eTuned 34.5 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eF3 32.1 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003e2.25\" three-layer baffle\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eCut for the Xv4 15\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-stats\"\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e2.17\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\"\u003e34.5\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz tuning\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e32.1\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz F3 anechoic\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e45.4\u003c\/span\u003e\u003cspan class=\"l\"\u003esq in port area\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhy this driver is vented at 34.5 Hz\u003c\/h3\u003e\n  \u003cp\u003eThe Xv4 15 is Fi's 15 inch at 39.3 Hz, a Qts of 0.55, 40.0 litres of Vas and 1500 W RMS. This cabinet gives it 2.17 cubic feet net behind a 2.25 inch three-layer baffle, vented at 34.5 Hz through a 45.4 square inch slot beside the woofer, for an anechoic F3 of 32.1 Hz in a 36 by 18 by 14.0 inch front-firing box.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThreaded insert kit ships with this box.\u003c\/strong\u003e Fi Car Audio does not publish the mounting hole locations for the Xv4 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with one kit.\u003c\/p\u003e\n  \u003cp\u003eFi lists no sealed box for the Xv4 at all; it is a ported motor and this is the box it is meant for. The slot is gated at 1500 W, Fi's own rating: the channel runs 19.7 m\/s and the mouth 13.6, and the cone peaks at 9.6 of its 27 mm with the subsonic filter in place. Fi's own ported recommendation for the Xv4 15 is 3 to 5 cubic feet at 32 Hz.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhat makes it Professional\u003c\/h3\u003e\n  \u003cdiv class=\"df-grid\"\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThree-layer baffle, flush mount\u003c\/h4\u003e\n\u003cp\u003eThree layers of 3\/4 inch Langboard Elite make a 2.25 inch\n    front. The outer layer is routed to the flange, so the woofer sits flush with the face; the two layers behind it\n    carry the mounting hardware and the load.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eFi Car Audio logo acrylic\u003c\/h4\u003e\n\u003cp\u003eA glossy black acrylic insert with the Fi Car Audio mark sits in the outer\n    layer beside the woofer. It is standard on every Professional cabinet.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThreaded insert kit ships with this box\u003c\/h4\u003e\n\u003cp\u003eThreaded insert kit included, inserts NOT pre-installed: the manufacturer publishes no mounting hole locations, so the kit ships with the box for installation when the woofer goes in: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, allen key and gasket tape.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003ePort gated at 1500 W\u003c\/h4\u003e\n\u003cp\u003eThe 45.4 square inch slot beside the woofer is sized so the\n    channel runs 19.7 metres per second and the mouth 13.6 metres per second at the driver's rated power, under the\n    17 metres per second where a slot starts to chuff. The channel runs 7.50 inches along its wall and turns once along the back wall for another 22.67 inches, which is why a 34.5 Hz tuning fits a 14.00 inch deep box.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhy this is a Professional build\u003c\/h4\u003e\n\u003cp\u003eEvery driver is run through the Performance Optimized wedge and down-fire before this chassis; the Professional box is where a driver lands when that smaller envelope, 30 inches wide and 18 inches deep with a triangular side port, cannot give it what it needs at its rated power. The Xv4 15 did not clear the port gate there. The calmest wedge port that fits that envelope is 38.1 square inches at 29.5 by 11.25 by 17.98 inches, and its mouth runs 17.8 metres per second at 1500 W against the 17 metres per second line where a port starts to chuff. That port would stay clean to about 1375 W. The slot on this box reaches 45.4 square inches and holds the mouth at 13.6 metres per second at 1500 W.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhat the price covers\u003c\/h4\u003e\n\u003cp\u003eEvery Professional cabinet is priced the same way, by its size: this one is 5.25 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 67 lb parcel and checkout adds nothing.\u003c\/p\u003e\n\u003c\/div\u003e\n    \n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe cabinet\u003c\/h3\u003e\n  \u003cp\u003e36.00\" W x 18.00\" H x 14.00\" D external. Two windowed braces run front to back either side of the woofer, clearing the cutout by two and a half inches. The box ships dry: polyfill detunes a ported alignment. Inside the 36 by 18 Professional envelope for a single 15, 14.0 inches deep. 15.500 inch frame, flush in the outer baffle layer, 13.875 inch cutout, 8.38 inches of mounting depth. It ships as a parcel.\u003c\/p\u003e\n  \u003cp\u003eFi publishes its Thiele-Small table and a one-way Xmax of 27 mm on the Xv4 15 product page, but does not say how the Xmax was measured, so we size port and power against it rather than past it. Fi publishes a single parameter set for the Xv4 15 that covers both the dual 1 and dual 2 ohm coils, and no motor strength for the 15, so cone travel is sized on the alignment route. Tuning includes a 1.5 Hz fold loss that is an estimate, not a bench measurement. Fi Car Audio does not publish the mounting hole locations for the Xv4 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with one kit.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe numbers to respect\u003c\/h3\u003e\n  \n  \u003cp\u003eSet a 27 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in\n  place the cone reaches 9.6 mm of its 27.0 mm at 1500 W.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":47368489074777,"sku":"Pro 15-P FI XV4","price":554.99,"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_31f39816-d50f-4151-93e7-570d5354bf6f.jpg?v=1790974993"},{"product_id":"professional-series-ported-dual-15-enclosure-fi-car-audio-xv4-15","title":"Professional Series Ported Dual 15\" Enclosure | Fi Car Audio Xv4 15","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%,#001a91 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14px;text-align:left;border-bottom:1px solid #44403c;font-weight:700}.df-tier th.on{background:#001264;color:#99abff}.df-tier td{padding:11px 14px;border-bottom:1px solid #292524;color:#a8a29e;font-size:.88em;vertical-align:top;line-height:1.55}.df-tier td.a{color:#d6d3d1;font-weight:700;background:#1c1917;width:19%}.df-tier td.on{background:rgba(91,120,255,.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\n\u003cdiv class=\"df-hero\"\u003e\n  \u003ch2\u003eProline X Professional 15\" Ported\u003c\/h2\u003e\n  \u003cp\u003eA ported fifteen inch box for a pair of Xv4 15, one shared chamber vented at 35.0 Hz\u003c\/p\u003e\n  \u003cdiv class=\"df-badges\"\u003e\n    \u003cspan class=\"df-badge\"\u003e3.31 cu ft net\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eTuned 35.0 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eF3 36.4 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003e2.25\" three-layer baffle\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eCut for the Xv4 15\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-stats\"\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e3.31\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\"\u003e35.0\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz tuning\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e36.4\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz F3 anechoic\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e70.1\u003c\/span\u003e\u003cspan class=\"l\"\u003esq in port area\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhy this driver is vented at 35.0 Hz\u003c\/h3\u003e\n  \u003cp\u003eThis cabinet holds two Xv4 15 in 3.311 cubic feet net, vented at 35.0 Hz through a 70.1 square inch port. F3 lands at 36.4 Hz with 0.70 dB of passband ripple. It measures 46.00 inches wide, 18.00 tall and 15.50 deep.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThreaded insert kit ships with this box.\u003c\/strong\u003e Fi Car Audio does not publish the mounting hole locations for the Xv4 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with two kits, one per woofer.\u003c\/p\u003e\n  \u003cp\u003eBoth drivers share one chamber and one port rather than sitting in separate boxes, so the pair works against the whole volume and the port is sized for the pair rather than doubled. The port carries 70.1 square inches of area at 35.0 Hz, and the design power for the velocity and excursion checks is 3000 W for the pair. Passband ripple holds at 0.70 dB across the tuning, with F3 at 36.4 Hz.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhat makes it Professional\u003c\/h3\u003e\n  \u003cdiv class=\"df-grid\"\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThree-layer baffle, flush mount\u003c\/h4\u003e\n\u003cp\u003eThree layers of 3\/4 inch Langboard Elite make a 2.25 inch\n    front. The outer layer is routed to the flange, so the woofer sits flush with the face; the two layers behind it\n    carry the mounting hardware and the load.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eFi Car Audio logo acrylic\u003c\/h4\u003e\n\u003cp\u003eA glossy black acrylic insert with the Fi Car Audio mark sits in the outer\n    layer beside the woofer. It is standard on every Professional cabinet.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThreaded insert kit ships with this box\u003c\/h4\u003e\n\u003cp\u003eThreaded insert kit included, inserts NOT pre-installed: the manufacturer publishes no mounting hole locations, so the kit ships with the box for installation when the woofer goes in: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, allen key and gasket tape.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003ePort gated at 3000 W\u003c\/h4\u003e\n\u003cp\u003eThe 70.1 square inch slot beside the woofer is sized so the\n    channel runs 20.6 metres per second and the mouth 15.7 metres per second at the driver's rated power, under the\n    17 metres per second where a slot starts to chuff. The channel runs 7.50 inches along its wall and turns once along the back wall for another 18.97 inches, which is why a 35.0 Hz tuning fits a 15.50 inch deep box.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhy this is a Professional build\u003c\/h4\u003e\n\u003cp\u003eEvery driver is run through the Performance Optimized wedge and down-fire before this chassis; the Professional box is where a driver lands when that smaller envelope, 30 inches wide and 18 inches deep with a triangular side port, cannot give it what it needs at its rated power. The Xv4 15 did not clear the port gate there. The calmest wedge port that fits that envelope is 38.1 square inches at 29.5 by 11.25 by 17.98 inches, and its mouth runs 17.8 metres per second at 1500 W against the 17 metres per second line where a port starts to chuff. That port would stay clean to about 1375 W. The slot on this box reaches 70.1 square inches and holds the mouth at 15.7 metres per second at 3000 W.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhat the price covers\u003c\/h4\u003e\n\u003cp\u003eEvery Professional cabinet is priced the same way, by its size: this one is 7.43 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 74 lb parcel and checkout adds nothing.\u003c\/p\u003e\n\u003c\/div\u003e\n    \n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe cabinet\u003c\/h3\u003e\n  \u003cp\u003e46.00\" W x 18.00\" H x 15.50\" D external. A windowed brace runs front to back beside the woofer, clearing the cutout by two and a half inches. The box ships dry: polyfill detunes a ported alignment. This is our dual 15 inch Professional envelope, built around the Xv4 15's own frame and mounting depth, with both woofers on one face and the port on the left. It ships as a parcel.\u003c\/p\u003e\n  \u003cp\u003ePort mouth velocity peaks at 15.7 m\/s against the 17 m\/s point where a slot begins to chuff, and 20.6 m\/s in the channel, both measured at the pair's design power. Both drivers must be the same model and the same coil: mixing them puts unequal loads on one shared chamber, and neither driver sees the airspace it was picked for. Fi Car Audio does not publish the mounting hole locations for the Xv4 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with two kits, one per woofer.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe numbers to respect\u003c\/h3\u003e\n  \n  \u003cp\u003eSet a 28 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in\n  place the cone reaches 8.4 mm of its 27.0 mm at 3000 W.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":47368493400153,"sku":"Pro 15D-P FI XV4","price":699.99,"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_a2653d47-c5c3-4e04-a79b-0c2844cfc710.jpg?v=1790975027"},{"product_id":"professional-series-ported-15-enclosure-fi-car-audio-neo-3-5-15","title":"Professional Series Ported 15\" Enclosure | Fi Car Audio NEO 3.5 15","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%,#001a91 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solid #44403c;border-radius:8px;overflow:hidden;margin:18px 0}.df-enc-head{padding:12px 16px;font-size:.82em;font-weight:700;letter-spacing:.5px;text-transform:uppercase;color:#99abff;background:#001264}.df-enc-table{width:100%;border-collapse:collapse}.df-enc-table th{background:#0c0a09;color:#a8a29e;font-size:.78em;text-transform:uppercase;letter-spacing:.5px;padding:10px 14px;text-align:left;border-bottom:1px solid #44403c}.df-enc-table td{padding:12px 14px;border-bottom:1px solid #292524;color:#d6d3d1;font-size:.95em}.df-enc-table tr:last-child td{border-bottom:none}.df-opt td{background:#14532d;color:#fff;font-weight:600}.df-char{display:block;font-size:.78em;color:#a8a29e;font-weight:400;margin-top:2px}.df-opt .df-char{color:#86efac}.df-graph{background:#0c0a09;border:1px solid #44403c;border-radius:8px;padding:14px;margin:18px 0}.df-graph-title{font-size:.78em;font-weight:700;letter-spacing:1px;text-transform:uppercase;color:#a8a29e;margin:0 0 10px}.df-legend{display:flex;flex-wrap:wrap;gap:12px;margin-top:10px}.df-legend-item{display:flex;align-items:center;gap:6px;font-size:12px;color:#a8a29e}.df-sw{width:22px;height:3px;border-radius:2px;display:inline-block}.df-note{background:#292524;border:1px solid #44403c;border-radius:8px;padding:14px 16px;margin-top:10px}.df-note p{margin:0;color:#d6d3d1;font-size:13.5px;line-height:1.6}.df-link{color:#7089ff;text-decoration:underline}.df-cta{background:linear-gradient(135deg,#0c0a09 0%,#001a91 100%);padding:40px 36px;text-align:center;color:#fff}.df-cta h3{color:#fff;font-size:1.4em;margin:0 0 10px;border:none;padding:0}.df-cta p{opacity:.92;margin:0 auto;max-width:640px;color:#d6d3d1}.df-tier{overflow-x:auto;margin:18px 0;border:1px solid #44403c;border-radius:8px}.df-tier table{width:100%;border-collapse:collapse;min-width:660px}.df-tier th{background:#0c0a09;color:#a8a29e;font-size:.74em;text-transform:uppercase;letter-spacing:.6px;padding:12px 14px;text-align:left;border-bottom:1px solid #44403c;font-weight:700}.df-tier th.on{background:#001264;color:#99abff}.df-tier td{padding:11px 14px;border-bottom:1px solid #292524;color:#a8a29e;font-size:.88em;vertical-align:top;line-height:1.55}.df-tier td.a{color:#d6d3d1;font-weight:700;background:#1c1917;width:19%}.df-tier td.on{background:rgba(91,120,255,.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\n\u003cdiv class=\"df-hero\"\u003e\n  \u003ch2\u003eProline X Professional 15\" Ported\u003c\/h2\u003e\n  \u003cp\u003eOne NEO 3.5 15 in a front-firing box, vented at 34.5 Hz on a three-layer flush-mount baffle\u003c\/p\u003e\n  \u003cdiv class=\"df-badges\"\u003e\n    \u003cspan class=\"df-badge\"\u003e2.98 cu ft net\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eTuned 34.5 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eF3 30.8 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003e2.25\" three-layer baffle\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eCut for the NEO 3.5 15\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-stats\"\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e2.98\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\"\u003e34.5\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz tuning\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e30.8\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz F3 anechoic\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e61.9\u003c\/span\u003e\u003cspan class=\"l\"\u003esq in port area\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhy this driver is vented at 34.5 Hz\u003c\/h3\u003e\n  \u003cp\u003eThe NEO 3.5 15 is Fi's 15 inch at 30.4 Hz, a Qts of 0.43, 75.0 litres of Vas and 2000 W RMS. This cabinet gives it 2.98 cubic feet net behind a 2.25 inch three-layer baffle, vented at 34.5 Hz through a 61.9 square inch slot beside the woofer, for an anechoic F3 of 30.8 Hz in a 36 by 18 by 17.5 inch front-firing box.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThreaded insert kit ships with this box.\u003c\/strong\u003e Fi Car Audio does not publish the mounting hole locations for the NEO 3.5 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with one kit.\u003c\/p\u003e\n  \u003cp\u003eFi publishes ported figures only for the NEO line, and with a Qts of 0.43 a sealed box would be overdamped. The slot is gated at 2000 W, Fi's own rating: the channel runs 19.5 m\/s and the mouth 14.5, and the cone peaks at 11.5 of its 34 mm with the subsonic filter in place. Fi's own ported recommendation for its 15 inch NEO motors is 3 to 5 cubic feet.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhat makes it Professional\u003c\/h3\u003e\n  \u003cdiv class=\"df-grid\"\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThree-layer baffle, flush mount\u003c\/h4\u003e\n\u003cp\u003eThree layers of 3\/4 inch Langboard Elite make a 2.25 inch\n    front. The outer layer is routed to the flange, so the woofer sits flush with the face; the two layers behind it\n    carry the mounting hardware and the load.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eFi Car Audio logo acrylic\u003c\/h4\u003e\n\u003cp\u003eA glossy black acrylic insert with the Fi Car Audio mark sits in the outer\n    layer beside the woofer. It is standard on every Professional cabinet.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThreaded insert kit ships with this box\u003c\/h4\u003e\n\u003cp\u003eThreaded insert kit included, inserts NOT pre-installed: the manufacturer publishes no mounting hole locations, so the kit ships with the box for installation when the woofer goes in: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, allen key and gasket tape.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003ePort gated at 2000 W\u003c\/h4\u003e\n\u003cp\u003eThe 61.9 square inch slot beside the woofer is sized so the\n    channel runs 19.5 metres per second and the mouth 14.5 metres per second at the driver's rated power, under the\n    17 metres per second where a slot starts to chuff. The channel runs 10.00 inches along its wall and turns once along the back wall for another 17.73 inches, which is why a 34.5 Hz tuning fits a 17.50 inch deep box.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhy this is a Professional build\u003c\/h4\u003e\n\u003cp\u003eEvery driver is run through the Performance Optimized wedge and down-fire before this chassis; the Professional box is where a driver lands when that smaller envelope, 30 inches wide and 18 inches deep with a triangular side port, cannot give it what it needs at its rated power. The NEO 3.5 15 does not fit that envelope at all: no tuning, width or depth inside it carries an 11.00 inch deep 15 inch driver at 2000 W. This box is the chassis with the width, depth and port to carry it.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhat the price covers\u003c\/h4\u003e\n\u003cp\u003eEvery Professional cabinet is priced the same way, by its size: this one is 6.56 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 72 lb parcel and checkout adds nothing.\u003c\/p\u003e\n\u003c\/div\u003e\n    \n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe cabinet\u003c\/h3\u003e\n  \u003cp\u003e36.00\" W x 18.00\" H x 17.50\" D external. Two windowed braces run front to back either side of the woofer, clearing the cutout by two and a half inches. The box ships dry: polyfill detunes a ported alignment. Inside the 36 by 18 Professional envelope for a single 15, 17.5 inches deep. 15.625 inch frame, flush in the outer baffle layer, 14.125 inch cutout, 11.00 inches of mounting depth. It ships as a parcel.\u003c\/p\u003e\n  \u003cp\u003eFi publishes its Thiele-Small table and a one-way Xmax of 34 mm on the NEO 3.5 15 product page, but does not say how the Xmax was measured, so we size port and power against it rather than past it. The printed Qts of 0.43 sits about 5 percent from the 0.45 that Fi's own Qes and Qms reproduce; the box was solved on the printed figure and checked against both. Tuning includes a 1.5 Hz fold loss that is an estimate, not a bench measurement. Fi Car Audio does not publish the mounting hole locations for the NEO 3.5 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with one kit.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe numbers to respect\u003c\/h3\u003e\n  \n  \u003cp\u003eSet a 27 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in\n  place the cone reaches 11.5 mm of its 34.0 mm at 2000 W.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":47368493924441,"sku":"Pro 15-P FI NEO35","price":637.99,"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_609f5f57-b68e-433a-9f1e-7060e0ebef4f.jpg?v=1790975038"},{"product_id":"professional-series-ported-dual-15-enclosure-fi-car-audio-neo-3-5-15","title":"Professional Series Ported Dual 15\" Enclosure | Fi Car Audio NEO 3.5 15","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 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solid #44403c;border-radius:8px;overflow:hidden;margin:18px 0}.df-enc-head{padding:12px 16px;font-size:.82em;font-weight:700;letter-spacing:.5px;text-transform:uppercase;color:#99abff;background:#001264}.df-enc-table{width:100%;border-collapse:collapse}.df-enc-table th{background:#0c0a09;color:#a8a29e;font-size:.78em;text-transform:uppercase;letter-spacing:.5px;padding:10px 14px;text-align:left;border-bottom:1px solid #44403c}.df-enc-table td{padding:12px 14px;border-bottom:1px solid #292524;color:#d6d3d1;font-size:.95em}.df-enc-table tr:last-child td{border-bottom:none}.df-opt td{background:#14532d;color:#fff;font-weight:600}.df-char{display:block;font-size:.78em;color:#a8a29e;font-weight:400;margin-top:2px}.df-opt .df-char{color:#86efac}.df-graph{background:#0c0a09;border:1px solid #44403c;border-radius:8px;padding:14px;margin:18px 0}.df-graph-title{font-size:.78em;font-weight:700;letter-spacing:1px;text-transform:uppercase;color:#a8a29e;margin:0 0 10px}.df-legend{display:flex;flex-wrap:wrap;gap:12px;margin-top:10px}.df-legend-item{display:flex;align-items:center;gap:6px;font-size:12px;color:#a8a29e}.df-sw{width:22px;height:3px;border-radius:2px;display:inline-block}.df-note{background:#292524;border:1px solid #44403c;border-radius:8px;padding:14px 16px;margin-top:10px}.df-note p{margin:0;color:#d6d3d1;font-size:13.5px;line-height:1.6}.df-link{color:#7089ff;text-decoration:underline}.df-cta{background:linear-gradient(135deg,#0c0a09 0%,#001a91 100%);padding:40px 36px;text-align:center;color:#fff}.df-cta h3{color:#fff;font-size:1.4em;margin:0 0 10px;border:none;padding:0}.df-cta p{opacity:.92;margin:0 auto;max-width:640px;color:#d6d3d1}.df-tier{overflow-x:auto;margin:18px 0;border:1px solid #44403c;border-radius:8px}.df-tier table{width:100%;border-collapse:collapse;min-width:660px}.df-tier th{background:#0c0a09;color:#a8a29e;font-size:.74em;text-transform:uppercase;letter-spacing:.6px;padding:12px 14px;text-align:left;border-bottom:1px solid #44403c;font-weight:700}.df-tier th.on{background:#001264;color:#99abff}.df-tier td{padding:11px 14px;border-bottom:1px solid #292524;color:#a8a29e;font-size:.88em;vertical-align:top;line-height:1.55}.df-tier td.a{color:#d6d3d1;font-weight:700;background:#1c1917;width:19%}.df-tier td.on{background:rgba(91,120,255,.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\n\u003cdiv class=\"df-hero\"\u003e\n  \u003ch2\u003eProline X Professional 15\" Ported\u003c\/h2\u003e\n  \u003cp\u003eA ported fifteen inch box for a pair of NEO 3.5 15, one shared chamber vented at 29.0 Hz\u003c\/p\u003e\n  \u003cdiv class=\"df-badges\"\u003e\n    \u003cspan class=\"df-badge\"\u003e3.73 cu ft net\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eTuned 29.0 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eF3 35.5 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003e2.25\" three-layer baffle\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eCut for the NEO 3.5 15\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-stats\"\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e3.73\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\"\u003e29.0\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz tuning\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e35.5\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz F3 anechoic\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e70.1\u003c\/span\u003e\u003cspan class=\"l\"\u003esq in port area\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhy this driver is vented at 29.0 Hz\u003c\/h3\u003e\n  \u003cp\u003eThis cabinet holds two NEO 3.5 15 in 3.732 cubic feet net, vented at 29.0 Hz through a 70.1 square inch port. F3 lands at 35.5 Hz with 0.15 dB of passband ripple. It measures 46.00 inches wide, 18.00 tall and 18.00 deep.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThreaded insert kit ships with this box.\u003c\/strong\u003e Fi Car Audio does not publish the mounting hole locations for the NEO 3.5 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with two kits, one per woofer.\u003c\/p\u003e\n  \u003cp\u003eBoth drivers share one chamber and one port rather than sitting in separate boxes, so the pair works against the whole volume and the port is sized for the pair rather than doubled. The port carries 70.1 square inches of area at 29.0 Hz, and the design power for the velocity and excursion checks is 4000 W for the pair. Passband ripple holds at 0.15 dB across the tuning, with F3 at 35.5 Hz.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhat makes it Professional\u003c\/h3\u003e\n  \u003cdiv class=\"df-grid\"\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThree-layer baffle, flush mount\u003c\/h4\u003e\n\u003cp\u003eThree layers of 3\/4 inch Langboard Elite make a 2.25 inch\n    front. The outer layer is routed to the flange, so the woofer sits flush with the face; the two layers behind it\n    carry the mounting hardware and the load.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eFi Car Audio logo acrylic\u003c\/h4\u003e\n\u003cp\u003eA glossy black acrylic insert with the Fi Car Audio mark sits in the outer\n    layer beside the woofer. It is standard on every Professional cabinet.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThreaded insert kit ships with this box\u003c\/h4\u003e\n\u003cp\u003eThreaded insert kit included, inserts NOT pre-installed: the manufacturer publishes no mounting hole locations, so the kit ships with the box for installation when the woofer goes in: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, allen key and gasket tape.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003ePort gated at 4000 W\u003c\/h4\u003e\n\u003cp\u003eThe 70.1 square inch slot beside the woofer is sized so the\n    channel runs 21.4 metres per second and the mouth 16.3 metres per second at the driver's rated power, under the\n    17 metres per second where a slot starts to chuff. The channel runs 10.00 inches along its wall and turns once along the back wall for another 27.96 inches, which is why a 29.0 Hz tuning fits a 18.00 inch deep box.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhy this is a Professional build\u003c\/h4\u003e\n\u003cp\u003eEvery driver is run through the Performance Optimized wedge and down-fire before this chassis; the Professional box is where a driver lands when that smaller envelope, 30 inches wide and 18 inches deep with a triangular side port, cannot give it what it needs at its rated power. The NEO 3.5 15 does not fit that envelope at all: no tuning, width or depth inside it carries an 11.00 inch deep 15 inch driver at 2000 W. This box is the chassis with the width, depth and port to carry it.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhat the price covers\u003c\/h4\u003e\n\u003cp\u003eEvery Professional cabinet is priced the same way, by its size: this one is 8.62 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 83 lb parcel and checkout adds nothing.\u003c\/p\u003e\n\u003c\/div\u003e\n    \n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe cabinet\u003c\/h3\u003e\n  \u003cp\u003e46.00\" W x 18.00\" H x 18.00\" D external. A windowed brace runs front to back beside the woofer, clearing the cutout by two and a half inches. The box ships dry: polyfill detunes a ported alignment. This is our dual 15 inch Professional envelope, built around the NEO 3.5 15's own frame and mounting depth, with both woofers on one face and the port on the left. It ships as a parcel.\u003c\/p\u003e\n  \u003cp\u003ePort mouth velocity peaks at 16.3 m\/s against the 17 m\/s point where a slot begins to chuff, and 21.4 m\/s in the channel, both measured at the pair's design power. Both drivers must be the same model and the same coil: mixing them puts unequal loads on one shared chamber, and neither driver sees the airspace it was picked for. Fi Car Audio does not publish the mounting hole locations for the NEO 3.5 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with two kits, one per woofer.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe numbers to respect\u003c\/h3\u003e\n  \n  \u003cp\u003eSet a 23 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in\n  place the cone reaches 11.2 mm of its 34.0 mm at 4000 W.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":47368494973017,"sku":"Pro 15D-P FI NEO35","price":782.99,"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_5f39000b-dccd-405a-a896-3ab0ada959dc.jpg?v=1790975049"},{"product_id":"professional-series-ported-15-enclosure-fi-car-audio-neo-3-7-15","title":"Professional Series Ported 15\" Enclosure | Fi Car Audio NEO 3.7 15","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%,#001a91 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14px;text-align:left;border-bottom:1px solid #44403c;font-weight:700}.df-tier th.on{background:#001264;color:#99abff}.df-tier td{padding:11px 14px;border-bottom:1px solid #292524;color:#a8a29e;font-size:.88em;vertical-align:top;line-height:1.55}.df-tier td.a{color:#d6d3d1;font-weight:700;background:#1c1917;width:19%}.df-tier td.on{background:rgba(91,120,255,.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\n\u003cdiv class=\"df-hero\"\u003e\n  \u003ch2\u003eProline X Professional 15\" Ported\u003c\/h2\u003e\n  \u003cp\u003eOne NEO 3.7 15 in a front-firing box, vented at 35.0 Hz on a three-layer flush-mount baffle\u003c\/p\u003e\n  \u003cdiv class=\"df-badges\"\u003e\n    \u003cspan class=\"df-badge\"\u003e3.04 cu ft net\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eTuned 35.0 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eF3 30.9 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003e2.25\" three-layer baffle\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eCut for the NEO 3.7 15\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-stats\"\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e3.04\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\"\u003e35.0\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz tuning\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e30.9\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz F3 anechoic\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e66.0\u003c\/span\u003e\u003cspan class=\"l\"\u003esq in port area\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhy this driver is vented at 35.0 Hz\u003c\/h3\u003e\n  \u003cp\u003eThe NEO 3.7 15 is Fi's 15 inch at 33.3 Hz, a Qts of 0.38, 61.4 litres of Vas and 2500 W RMS. This cabinet gives it 3.04 cubic feet net behind a 2.25 inch three-layer baffle, vented at 35.0 Hz through a 66.0 square inch slot beside the woofer, for an anechoic F3 of 30.9 Hz in a 36 by 18 by 18.0 inch front-firing box.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThreaded insert kit ships with this box.\u003c\/strong\u003e Fi Car Audio does not publish the mounting hole locations for the NEO 3.7 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with one kit.\u003c\/p\u003e\n  \u003cp\u003eFi publishes ported figures only for the NEO line, and with a Qts of 0.37 a sealed box would be overdamped. The slot is gated at 2500 W, Fi's own rating: the channel runs 22.2 m\/s and the mouth 16.7, and the cone peaks at 11.8 of its 34 mm with the subsonic filter in place. Fi's own ported recommendation for its 15 inch NEO motors is 3 to 5 cubic feet.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhat makes it Professional\u003c\/h3\u003e\n  \u003cdiv class=\"df-grid\"\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThree-layer baffle, flush mount\u003c\/h4\u003e\n\u003cp\u003eThree layers of 3\/4 inch Langboard Elite make a 2.25 inch\n    front. The outer layer is routed to the flange, so the woofer sits flush with the face; the two layers behind it\n    carry the mounting hardware and the load.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eFi Car Audio logo acrylic\u003c\/h4\u003e\n\u003cp\u003eA glossy black acrylic insert with the Fi Car Audio mark sits in the outer\n    layer beside the woofer. It is standard on every Professional cabinet.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThreaded insert kit ships with this box\u003c\/h4\u003e\n\u003cp\u003eThreaded insert kit included, inserts NOT pre-installed: the manufacturer publishes no mounting hole locations, so the kit ships with the box for installation when the woofer goes in: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, allen key and gasket tape.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003ePort gated at 2500 W\u003c\/h4\u003e\n\u003cp\u003eThe 66.0 square inch slot beside the woofer is sized so the\n    channel runs 22.2 metres per second and the mouth 16.7 metres per second at the driver's rated power, under the\n    17 metres per second where a slot starts to chuff. The channel runs 10.25 inches along its wall and turns once along the back wall for another 17.75 inches, which is why a 35.0 Hz tuning fits a 18.00 inch deep box.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhy this is a Professional build\u003c\/h4\u003e\n\u003cp\u003eEvery driver is run through the Performance Optimized wedge and down-fire before this chassis; the Professional box is where a driver lands when that smaller envelope, 30 inches wide and 18 inches deep with a triangular side port, cannot give it what it needs at its rated power. The NEO 3.7 15 does not fit that envelope at all: no tuning, width or depth inside it carries an 11.00 inch deep 15 inch driver at 2500 W. This box is the chassis with the width, depth and port to carry it.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhat the price covers\u003c\/h4\u003e\n\u003cp\u003eEvery Professional cabinet is priced the same way, by its size: this one is 6.75 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 73 lb parcel and checkout adds nothing.\u003c\/p\u003e\n\u003c\/div\u003e\n    \n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe cabinet\u003c\/h3\u003e\n  \u003cp\u003e36.00\" W x 18.00\" H x 18.00\" D external. Two windowed braces run front to back either side of the woofer, clearing the cutout by two and a half inches. The box ships dry: polyfill detunes a ported alignment. Inside the 36 by 18 Professional envelope for a single 15, 18.0 inches deep. 15.625 inch frame, flush in the outer baffle layer, 14.125 inch cutout, 11.00 inches of mounting depth. It ships as a parcel.\u003c\/p\u003e\n  \u003cp\u003eFi publishes its Thiele-Small table and a one-way Xmax of 34 mm on the NEO 3.7 15 product page, but does not say how the Xmax was measured, so we size port and power against it rather than past it. Fi's printed moving mass for the NEO 3.7 15 is the MT 15's figure carried across, so we left it out; Fs, Qts and Vas agree with the 12 and 18 in the same family and the alignment rests on those. The slot mouth runs 16.7 m\/s at Fi's rating against a 17 m\/s limit, so this is a box to run at its rating, not past it. Tuning includes a 1.5 Hz fold loss that is an estimate, not a bench measurement. Fi Car Audio does not publish the mounting hole locations for the NEO 3.7 15, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer, and this box ships with one kit.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe numbers to respect\u003c\/h3\u003e\n  \n  \u003cp\u003eSet a 28 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in\n  place the cone reaches 11.8 mm of its 34.0 mm at 2500 W.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":47368496840793,"sku":"Pro 15-P FI NEO37","price":651.99,"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_e556230d-6687-4fdf-8aa8-3a05ec9a7b7a.jpg?v=1790975059"},{"product_id":"performance-optimized-wedge-sealed-12-enclosure-fi-car-audio-alpha-12","title":"Performance Optimized Wedge Sealed 12\" Enclosure | Fi Car Audio Alpha 12","description":"\u003cdiv class=\"po-wrap\"\u003e\n\u003cstyle\u003e\n.po-wrap{font-family:'Helvetica Neue',Arial,sans-serif;line-height:1.8;color:#1e293b;max-width:1200px;margin:0 auto;background:#fff}\n.po-hero{background:linear-gradient(135deg,#0f172a 0%,#8b5a2b 100%);padding:60px 40px;text-align:center;color:#fff}\n.po-hero .po-title{font-size:2.6em;font-weight:800;text-transform:uppercase;letter-spacing:2px;margin:0 0 10px 0;color:#fff}\n.po-hero .po-subtitle{font-size:1.2em;font-weight:300;opacity:.9;margin:0 0 30px 0}\n.po-badges{display:flex;justify-content:center;flex-wrap:wrap;gap:12px;margin-top:20px}\n.po-badge{background:rgba(184,115,51,.2);border:1px solid #b87333;color:#d99058;padding:8px 20px;border-radius:20px;font-size:.9em;font-weight:600;letter-spacing:.5px}\n.po-section{padding:50px 40px;border-bottom:1px solid #e2e8f0;background:#fff}\n.po-section:nth-child(even){background:#fef3e7}\n.po-section h2{color:#8b5a2b;font-size:2em;font-weight:700;margin:0 0 20px 0;padding-bottom:12px;border-bottom:3px solid #b87333}\n.po-section h3{color:#0f172a;font-size:1.4em;font-weight:600;margin:30px 0 15px 0}\n.po-section p{font-size:1.05em;color:#334155;margin-bottom:18px}\n.po-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:24px;margin:30px 0}\n.po-card{background:#fff;border:1px solid #e2e8f0;border-top:4px solid #b87333;padding:25px;border-radius:4px}\n.po-card h4{color:#8b5a2b;font-size:1.15em;font-weight:700;margin:0 0 12px 0;text-transform:uppercase;letter-spacing:1px}\n.po-card p{font-size:.98em;color:#475569;margin:0}\n.po-highlight{background:#fef3e7;border-left:4px solid #b87333;padding:25px 30px;margin:30px 0;border-radius:4px}\n.po-highlight p{color:#1e293b;margin:0;font-size:1.05em}\n.po-cta{background:linear-gradient(135deg,#0f172a 0%,#8b5a2b 100%);padding:60px 40px;text-align:center;color:#fff}\n.po-cta h2{font-size:2.2em;font-weight:700;margin:0 0 20px 0;color:#fff;border:none;padding:0}\n.po-cta p{font-size:1.15em;opacity:.92;max-width:800px;margin:0 auto 20px auto;color:#fff}\n@media (max-width:768px){.po-hero{padding:40px 20px}.po-hero .po-title{font-size:1.8em}.po-section{padding:30px 20px}.po-section h2{font-size:1.6em}.po-grid{grid-template-columns:1fr}.po-cta{padding:40px 20px}.po-cta h2{font-size:1.6em}}\n\u003c\/style\u003e\n\u003cdiv class=\"po-hero\"\u003e\n\u003cp class=\"po-title\"\u003ePerformance Optimized Wedge | Fi Car Audio Alpha 12\u003c\/p\u003e\n\u003cp class=\"po-subtitle\"\u003e12\" Sealed Wedge Enclosure | Rear-Firing Trunk-Load Design\u003c\/p\u003e\n\u003cdiv class=\"po-badges\"\u003e\n\u003cspan class=\"po-badge\"\u003e0.80 ft3 Net\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003e0.92 ft3 Gross\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eQtc 0.60\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eSingle Chamber Wedge\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003e18.66\" x 15\" x 7.57\/13.03\"\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eThe Fi Car Audio Alpha 12 in a Sealed Wedge\u003c\/h2\u003e\n\u003cp\u003eThe Alpha 12 is the 12 inch from Fi Car Audio's Alpha v1 line: 1000 watts RMS, 17 mm of one-way excursion on 480 square centimeters of cone, and 6.125 inches of mounting depth. Every figure comes from the Thiele-Small and technical tables Fi prints on its Alpha Series product page, including the 0.11 cubic foot driver displacement, and the parameters check against each other: the printed Qts reproduces from Qes and Qms, and Fi's moving mass agrees with its Fs, Vas and cone area.\u003c\/p\u003e\n\u003cdiv class=\"po-highlight\"\u003e\u003cp\u003e0.80 cubic feet net is Fi's own minimum recommended sealed volume for the Alpha 12. On Fi's figures, Fs 36.2 Hz, Qts 0.41 and Vas 25.85 liters, that is Qtc 0.600 with half power at 64.1 Hz. Fi publishes one parameter set for the Alpha 12 that covers the S1, S2 and S4 single coil versions, so one alignment serves all three. Fi's own recommended sealed range for the Alpha 12 is 0.8 to 1.5 cubic feet, which reads Qtc 0.60 to 0.52.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eTrunk-Load Wedge Design Explained\u003c\/h2\u003e\n\u003cp\u003eThe driver mounts on the vertical trunk-lid-side face and fires rearward into the trunk cavity.\u003c\/p\u003e\n\u003cdiv class=\"po-grid\"\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eSeat-Side Face Matches Seat Lean\u003c\/h4\u003e\n\u003cp\u003eAngled face matches the roughly 20 degree factory seat lean.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eTrunk-Lid-Side Face Fires the Woofer\u003c\/h4\u003e\n\u003cp\u003eVertical baffle, cone firing rearward into the trunk cavity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eTrunk Cavity Loading\u003c\/h4\u003e\n\u003cp\u003eThe trunk acts as an acoustic extension for a smoother presentation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003ePreserves Trunk Cargo Space\u003c\/h4\u003e\n\u003cp\u003eThe wedge tucks against the seat back and the space in front stays usable.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eEngineered for the Fi Car Audio Alpha 12\u003c\/h2\u003e\n\u003cp\u003eHalf power lands at 64.1 Hz anechoic, before any cabin gain. Below Qtc 0.707 the rolloff starts early and gently and F3 sits above fc: a dry, tightly damped box. Fi publishes the driver displacement, 0.11 cubic feet, and it is taken out of the net figure.\u003c\/p\u003e\n\u003ch3\u003eAlignment Numbers\u003c\/h3\u003e\n\u003ctable class=\"df-tier\"\u003e\n\u003ctr\u003e\n\u003cth\u003eDriver\u003c\/th\u003e\n\u003cth\u003eSystem Qtc\u003c\/th\u003e\n\u003cth\u003efc\u003c\/th\u003e\n\u003cth\u003eF3\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAlpha 12 S1, S2 or S4\u003c\/td\u003e\n\u003ctd\u003eQtc 0.600\u003c\/td\u003e\n\u003ctd\u003e53.0 Hz\u003c\/td\u003e\n\u003ctd\u003e64.1 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch3\u003eMounting Geometry\u003c\/h3\u003e\n\u003cp\u003eThe baffle is cut to 11.0625 in, Fi's published cutout, under the 12.625 in frame. The rear panel rakes 20 degrees, so the cavity deepens from 7.57 in at the top to 13.03 in at the base, and the 6.125 in motor clears it with 0.75 in to spare. Fi prints no bolt circle for the Alpha 12, so the baffle ships undrilled with a threaded insert kit and stainless machine screws: set the driver in the recess, mark its holes, drill, press the inserts and bolt it down.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eWhat the Numbers Rest On\u003c\/h2\u003e\n\u003cdiv class=\"po-grid\"\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eLangboard Elite MDF\u003c\/h4\u003e\n\u003cp\u003ePremium 3\/4 in MDF throughout.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eV-Groove and Dado Joinery\u003c\/h4\u003e\n\u003cp\u003eCNC cut V-grooves at every panel intersection, sides and brace seated in dados.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eDouble-Layer 1.5\" Front Baffle\u003c\/h4\u003e\n\u003cp\u003eTwo bonded 3\/4 in MDF sheets at the driver face, the outer layer machined as a flush recess.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eFi's Published Parameters\u003c\/h4\u003e\n\u003cp\u003eFs 36.2 Hz, Qts 0.41, Qes 0.44, Qms 6.43, Vas 25.85 L, Sd 480 cm2, Cms 0.08015 mm\/N, Mms 241 g, Bl 10.0 \/ 14.1 \/ 20.2 N\/A (S1 \/ S2 \/ S4), Re 0.8 \/ 1.6 \/ 3.3 ohms, sensitivity 86.3 dB 1W\/1m.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eWiring the Fi Car Audio Alpha 12 to Your Amplifier\u003c\/h2\u003e\n\u003cp\u003eThe single coil comes as S1, S2 or S4: 1, 2 or 4 ohms, wired straight to the amplifier. Confirm the final load against your amplifier's minimum stable impedance before powering the system.\u003c\/p\u003e\n\u003cp\u003ePower handling is 1000 watts RMS per driver. Aim for roughly 700 to 1000 watts at the impedance you wire.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eBuilt in Tennessee, Backed by Audio Intensity\u003c\/h2\u003e\n\u003cp\u003eCut and assembled in Tullahoma, Tennessee on our own CNC equipment. Finished in plush black carpet with the gloss black acrylic baffle insert, one pre-wired terminal cup, 12 gauge OFC to the driver position. Polyfill wall lining installed. Threaded insert kit and stainless machine screws in the box. 1 year limited warranty. Enclosure only, the driver is purchased separately. Call or text 931-563-5151.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-cta\"\u003e\n\u003ch2\u003eFi Car Audio Alpha 12: Cut for the Driver\u003c\/h2\u003e\n\u003cp\u003e0.80 cubic feet net at Qtc 0.600, F3 64.1 Hz, cut direct fit and built to order in Tennessee.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Black","offer_id":47368499363929,"sku":"PO 12-S W FI ALPHA BB","price":319.99,"currency_code":"USD","in_stock":true},{"title":"None","offer_id":47368499396697,"sku":"PO 12-S W FI ALPHA B","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_e1ffd816-a6ee-4e52-bf4d-90d48d5b6edc.jpg?v=1790975074"},{"product_id":"performance-optimized-wedge-sealed-dual-12-enclosure-fi-car-audio-alpha-12","title":"Performance Optimized Wedge Sealed Dual 12\" Enclosure | Fi Car Audio Alpha 12","description":"\u003cdiv class=\"po-wrap\"\u003e\n\u003cstyle\u003e\n.po-wrap{font-family:'Helvetica Neue',Arial,sans-serif;line-height:1.8;color:#1e293b;max-width:1200px;margin:0 auto;background:#fff}\n.po-hero{background:linear-gradient(135deg,#0f172a 0%,#8b5a2b 100%);padding:60px 40px;text-align:center;color:#fff}\n.po-hero .po-title{font-size:2.6em;font-weight:800;text-transform:uppercase;letter-spacing:2px;margin:0 0 10px 0;color:#fff}\n.po-hero .po-subtitle{font-size:1.2em;font-weight:300;opacity:.9;margin:0 0 30px 0}\n.po-badges{display:flex;justify-content:center;flex-wrap:wrap;gap:12px;margin-top:20px}\n.po-badge{background:rgba(184,115,51,.2);border:1px solid #b87333;color:#d99058;padding:8px 20px;border-radius:20px;font-size:.9em;font-weight:600;letter-spacing:.5px}\n.po-section{padding:50px 40px;border-bottom:1px solid #e2e8f0;background:#fff}\n.po-section:nth-child(even){background:#fef3e7}\n.po-section h2{color:#8b5a2b;font-size:2em;font-weight:700;margin:0 0 20px 0;padding-bottom:12px;border-bottom:3px solid #b87333}\n.po-section h3{color:#0f172a;font-size:1.4em;font-weight:600;margin:30px 0 15px 0}\n.po-section p{font-size:1.05em;color:#334155;margin-bottom:18px}\n.po-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:24px;margin:30px 0}\n.po-card{background:#fff;border:1px solid #e2e8f0;border-top:4px solid #b87333;padding:25px;border-radius:4px}\n.po-card h4{color:#8b5a2b;font-size:1.15em;font-weight:700;margin:0 0 12px 0;text-transform:uppercase;letter-spacing:1px}\n.po-card p{font-size:.98em;color:#475569;margin:0}\n.po-highlight{background:#fef3e7;border-left:4px solid #b87333;padding:25px 30px;margin:30px 0;border-radius:4px}\n.po-highlight p{color:#1e293b;margin:0;font-size:1.05em}\n.po-cta{background:linear-gradient(135deg,#0f172a 0%,#8b5a2b 100%);padding:60px 40px;text-align:center;color:#fff}\n.po-cta h2{font-size:2.2em;font-weight:700;margin:0 0 20px 0;color:#fff;border:none;padding:0}\n.po-cta p{font-size:1.15em;opacity:.92;max-width:800px;margin:0 auto 20px auto;color:#fff}\n@media (max-width:768px){.po-hero{padding:40px 20px}.po-hero .po-title{font-size:1.8em}.po-section{padding:30px 20px}.po-section h2{font-size:1.6em}.po-grid{grid-template-columns:1fr}.po-cta{padding:40px 20px}.po-cta h2{font-size:1.6em}}\n\u003c\/style\u003e\n\u003cdiv class=\"po-hero\"\u003e\n\u003cp class=\"po-title\"\u003ePerformance Optimized Wedge | Dual Fi Car Audio Alpha 12\u003c\/p\u003e\n\u003cp class=\"po-subtitle\"\u003eDual 12\" Sealed Wedge Enclosure | Rear-Firing Trunk-Load Design\u003c\/p\u003e\n\u003cdiv class=\"po-badges\"\u003e\n\u003cspan class=\"po-badge\"\u003e0.80 ft3 Net per Chamber\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003e1.87 ft3 Gross\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eQtc 0.60\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eTwo Separate Chambers\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003e32.00\" x 16\" x 7.63\/13.46\"\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eA Pair of Fi Car Audio Alpha 12 in a Sealed Wedge\u003c\/h2\u003e\n\u003cp\u003eThe Alpha 12 is the 12 inch from Fi Car Audio's Alpha v1 line: 1000 watts RMS, 17 mm of one-way excursion on 480 square centimeters of cone, and 6.125 inches of mounting depth. Every figure comes from the Thiele-Small and technical tables Fi prints on its Alpha Series product page, including the 0.11 cubic foot driver displacement, and the parameters check against each other: the printed Qts reproduces from Qes and Qms, and Fi's moving mass agrees with its Fs, Vas and cone area.\u003c\/p\u003e\n\u003cdiv class=\"po-highlight\"\u003e\u003cp\u003e0.80 cubic feet net per chamber is Fi's own minimum recommended sealed volume for the Alpha 12. On Fi's figures, Fs 36.2 Hz, Qts 0.41 and Vas 25.85 liters, that is Qtc 0.600 with half power at 64.1 Hz. Fi publishes one parameter set for the Alpha 12 that covers the S1, S2 and S4 single coil versions, so one alignment serves all three. Fi's own recommended sealed range for the Alpha 12 is 0.8 to 1.5 cubic feet, which reads Qtc 0.60 to 0.52.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eTwo Fully Separate Chambers\u003c\/h2\u003e\n\u003cp\u003eA bonded full-height 3\/4 inch MDF divider splits the cabinet into two sealed chambers of 0.80 cubic feet net each, so every driver sees exactly the airspace printed on this page. Two drivers sharing one volume load each other; the divider removes that, and each chamber carries its own polyfill.\u003c\/p\u003e\n\u003cp\u003eThe cabinet is 32.00 inches wide, 16 tall, 7.63 inches deep at the top and 13.46 at the base. One shared side-mounted terminal cup feeds both driver positions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eTrunk-Load Wedge Design Explained\u003c\/h2\u003e\n\u003cp\u003eThe drivers mount on the vertical trunk-lid-side face and fire rearward into the trunk cavity.\u003c\/p\u003e\n\u003cdiv class=\"po-grid\"\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eSeat-Side Face Matches Seat Lean\u003c\/h4\u003e\n\u003cp\u003eAngled face matches the roughly 20 degree factory seat lean.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eTrunk-Lid-Side Face Fires the Woofer\u003c\/h4\u003e\n\u003cp\u003eVertical baffle, cone firing rearward into the trunk cavity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eTrunk Cavity Loading\u003c\/h4\u003e\n\u003cp\u003eThe trunk acts as an acoustic extension for a smoother presentation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003ePreserves Trunk Cargo Space\u003c\/h4\u003e\n\u003cp\u003eThe wedge tucks against the seat back and the space in front stays usable.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eEngineered for a pair of Fi Car Audio Alpha 12\u003c\/h2\u003e\n\u003cp\u003eHalf power lands at 64.1 Hz anechoic, before any cabin gain. Below Qtc 0.707 the rolloff starts early and gently and F3 sits above fc: a dry, tightly damped box. Fi publishes the driver displacement, 0.11 cubic feet, and it is taken out of the net figure.\u003c\/p\u003e\n\u003ch3\u003eAlignment Numbers (Per Chamber)\u003c\/h3\u003e\n\u003ctable class=\"df-tier\"\u003e\n\u003ctr\u003e\n\u003cth\u003eDriver (per chamber)\u003c\/th\u003e\n\u003cth\u003eSystem Qtc\u003c\/th\u003e\n\u003cth\u003efc\u003c\/th\u003e\n\u003cth\u003eF3\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAlpha 12 S1, S2 or S4\u003c\/td\u003e\n\u003ctd\u003eQtc 0.600\u003c\/td\u003e\n\u003ctd\u003e53.0 Hz\u003c\/td\u003e\n\u003ctd\u003e64.1 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch3\u003eMounting Geometry\u003c\/h3\u003e\n\u003cp\u003eThe baffle is cut to 11.0625 in, Fi's published cutout, under the 12.625 in frame. The rear panel rakes 20 degrees, so the cavity deepens from 7.63 in at the top to 13.46 in at the base, and the 6.125 in motor clears it with 1.01 in to spare. Fi prints no bolt circle for the Alpha 12, so the baffle ships undrilled with a threaded insert kit and stainless machine screws: set the driver in the recess, mark its holes, drill, press the inserts and bolt it down.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eWhat the Numbers Rest On\u003c\/h2\u003e\n\u003cdiv class=\"po-grid\"\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eLangboard Elite MDF\u003c\/h4\u003e\n\u003cp\u003ePremium 3\/4 in MDF throughout.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eV-Groove and Dado Joinery\u003c\/h4\u003e\n\u003cp\u003eCNC cut V-grooves at every panel intersection, sides and divider seated in dados.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eDouble-Layer 1.5\" Front Baffle\u003c\/h4\u003e\n\u003cp\u003eTwo bonded 3\/4 in MDF sheets at the driver face, the outer layer machined as a flush recess.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eFi's Published Parameters\u003c\/h4\u003e\n\u003cp\u003eFs 36.2 Hz, Qts 0.41, Qes 0.44, Qms 6.43, Vas 25.85 L, Sd 480 cm2, Cms 0.08015 mm\/N, Mms 241 g, Bl 10.0 \/ 14.1 \/ 20.2 N\/A (S1 \/ S2 \/ S4), Re 0.8 \/ 1.6 \/ 3.3 ohms, sensitivity 86.3 dB 1W\/1m.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eWiring a pair of Fi Car Audio Alpha 12 to Your Amplifier\u003c\/h2\u003e\n\u003cp\u003eA pair lands on 0.5 ohm parallel or 2 ohms series with S1 coils, 1 ohm parallel or 4 ohms series with S2, and 2 ohms parallel or 8 ohms series with S4. Anything under 1 ohm, and many amplifiers at 1 ohm, is outside what the amplifier is built for; series wiring is the safe default. Confirm the final load against your amplifier's minimum stable impedance before powering the system.\u003c\/p\u003e\n\u003cp\u003ePower handling is 1000 watts RMS per driver, 2000 across the pair. Aim for roughly 700 to 1000 watts per driver at the impedance you wire.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eBuilt in Tennessee, Backed by Audio Intensity\u003c\/h2\u003e\n\u003cp\u003eCut and assembled in Tullahoma, Tennessee on our own CNC equipment. Finished in plush black carpet with the gloss black acrylic baffle insert, one shared pre-wired terminal cup, 12 gauge OFC to both driver positions. Polyfill wall lining installed. Threaded insert kit and stainless machine screws in the box. 1 year limited warranty. Enclosure only, the drivers are purchased separately. Call or text 931-563-5151.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-cta\"\u003e\n\u003ch2\u003eDual Fi Car Audio Alpha 12: Cut for the Driver\u003c\/h2\u003e\n\u003cp\u003e0.80 cubic feet net per chamber at Qtc 0.600, F3 64.1 Hz, cut direct fit and built to order in Tennessee.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Black","offer_id":47368499429465,"sku":"PO 12D-S W FI ALPHA BB","price":389.99,"currency_code":"USD","in_stock":true},{"title":"None","offer_id":47368499462233,"sku":"PO 12D-S W FI ALPHA B","price":369.99,"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_f94e4bfc-7231-45b7-ab69-3ee404151462.jpg?v=1790975085"},{"product_id":"performance-optimized-wedge-sealed-15-enclosure-fi-car-audio-alpha-15","title":"Performance Optimized Wedge Sealed 15\" Enclosure | Fi Car Audio Alpha 15","description":"\u003cdiv class=\"po-wrap\"\u003e\n\u003cstyle\u003e\n.po-wrap{font-family:'Helvetica Neue',Arial,sans-serif;line-height:1.8;color:#1e293b;max-width:1200px;margin:0 auto;background:#fff}\n.po-hero{background:linear-gradient(135deg,#0f172a 0%,#8b5a2b 100%);padding:60px 40px;text-align:center;color:#fff}\n.po-hero .po-title{font-size:2.6em;font-weight:800;text-transform:uppercase;letter-spacing:2px;margin:0 0 10px 0;color:#fff}\n.po-hero .po-subtitle{font-size:1.2em;font-weight:300;opacity:.9;margin:0 0 30px 0}\n.po-badges{display:flex;justify-content:center;flex-wrap:wrap;gap:12px;margin-top:20px}\n.po-badge{background:rgba(184,115,51,.2);border:1px solid #b87333;color:#d99058;padding:8px 20px;border-radius:20px;font-size:.9em;font-weight:600;letter-spacing:.5px}\n.po-section{padding:50px 40px;border-bottom:1px solid #e2e8f0;background:#fff}\n.po-section:nth-child(even){background:#fef3e7}\n.po-section h2{color:#8b5a2b;font-size:2em;font-weight:700;margin:0 0 20px 0;padding-bottom:12px;border-bottom:3px solid #b87333}\n.po-section h3{color:#0f172a;font-size:1.4em;font-weight:600;margin:30px 0 15px 0}\n.po-section p{font-size:1.05em;color:#334155;margin-bottom:18px}\n.po-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:24px;margin:30px 0}\n.po-card{background:#fff;border:1px solid #e2e8f0;border-top:4px solid #b87333;padding:25px;border-radius:4px}\n.po-card h4{color:#8b5a2b;font-size:1.15em;font-weight:700;margin:0 0 12px 0;text-transform:uppercase;letter-spacing:1px}\n.po-card p{font-size:.98em;color:#475569;margin:0}\n.po-highlight{background:#fef3e7;border-left:4px solid #b87333;padding:25px 30px;margin:30px 0;border-radius:4px}\n.po-highlight p{color:#1e293b;margin:0;font-size:1.05em}\n.po-cta{background:linear-gradient(135deg,#0f172a 0%,#8b5a2b 100%);padding:60px 40px;text-align:center;color:#fff}\n.po-cta h2{font-size:2.2em;font-weight:700;margin:0 0 20px 0;color:#fff;border:none;padding:0}\n.po-cta p{font-size:1.15em;opacity:.92;max-width:800px;margin:0 auto 20px auto;color:#fff}\n@media (max-width:768px){.po-hero{padding:40px 20px}.po-hero .po-title{font-size:1.8em}.po-section{padding:30px 20px}.po-section h2{font-size:1.6em}.po-grid{grid-template-columns:1fr}.po-cta{padding:40px 20px}.po-cta h2{font-size:1.6em}}\n\u003c\/style\u003e\n\u003cdiv class=\"po-hero\"\u003e\n\u003cp class=\"po-title\"\u003ePerformance Optimized Wedge | Fi Car Audio Alpha 15\u003c\/p\u003e\n\u003cp class=\"po-subtitle\"\u003e15\" Sealed Wedge Enclosure | Rear-Firing Trunk-Load Design\u003c\/p\u003e\n\u003cdiv class=\"po-badges\"\u003e\n\u003cspan class=\"po-badge\"\u003e2.54 ft3 Net\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003e2.69 ft3 Gross\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eQtc 0.71\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eSingle Chamber Wedge\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003e29.50\" x 18\" x 10.17\/16.72\"\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eThe Fi Car Audio Alpha 15 in a Sealed Wedge\u003c\/h2\u003e\n\u003cp\u003eThe Alpha 15 is the 15 inch from Fi Car Audio's Alpha v1 line: 1000 watts RMS, 17 mm of one-way excursion on 810 square centimeters of cone, and 7.375 inches of mounting depth. Every figure comes from the Thiele-Small and technical tables Fi prints on its Alpha Series product page, including the 0.14 cubic foot driver displacement, and the parameters check against each other: the printed Qts reproduces from Qes and Qms, and Fi's moving mass agrees with its Fs, Vas and cone area.\u003c\/p\u003e\n\u003cdiv class=\"po-highlight\"\u003e\u003cp\u003e2.54 cubic feet net is the Butterworth volume, inside Fi's recommended 1.8 to 3.0 cubic feet. On Fi's figures, Fs 34.7 Hz, Qts 0.52 and Vas 61.00 liters, that is Qtc 0.707 with half power at 47.2 Hz. Fi publishes one parameter set for the Alpha 15 that covers the S1, S2 and S4 single coil versions, so one alignment serves all three. Fi's own recommended sealed range for the Alpha 15 is 1.8 to 3 cubic feet, which reads Qtc 0.77 to 0.68.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eTrunk-Load Wedge Design Explained\u003c\/h2\u003e\n\u003cp\u003eThe driver mounts on the vertical trunk-lid-side face and fires rearward into the trunk cavity.\u003c\/p\u003e\n\u003cdiv class=\"po-grid\"\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eSeat-Side Face Matches Seat Lean\u003c\/h4\u003e\n\u003cp\u003eAngled face matches the roughly 20 degree factory seat lean.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eTrunk-Lid-Side Face Fires the Woofer\u003c\/h4\u003e\n\u003cp\u003eVertical baffle, cone firing rearward into the trunk cavity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eTrunk Cavity Loading\u003c\/h4\u003e\n\u003cp\u003eThe trunk acts as an acoustic extension for a smoother presentation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003ePreserves Trunk Cargo Space\u003c\/h4\u003e\n\u003cp\u003eThe wedge tucks against the seat back and the space in front stays usable.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eEngineered for the Fi Car Audio Alpha 15\u003c\/h2\u003e\n\u003cp\u003eHalf power lands at 47.2 Hz anechoic, before any cabin gain. At Qtc 0.71 the response is maximally flat into the rolloff, so F3 and fc coincide. Fi publishes the driver displacement, 0.14 cubic feet, and it is taken out of the net figure.\u003c\/p\u003e\n\u003ch3\u003eAlignment Numbers\u003c\/h3\u003e\n\u003ctable class=\"df-tier\"\u003e\n\u003ctr\u003e\n\u003cth\u003eDriver\u003c\/th\u003e\n\u003cth\u003eSystem Qtc\u003c\/th\u003e\n\u003cth\u003efc\u003c\/th\u003e\n\u003cth\u003eF3\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAlpha 15 S1, S2 or S4\u003c\/td\u003e\n\u003ctd\u003eQtc 0.707\u003c\/td\u003e\n\u003ctd\u003e47.2 Hz\u003c\/td\u003e\n\u003ctd\u003e47.2 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch3\u003eMounting Geometry\u003c\/h3\u003e\n\u003cp\u003eThe baffle is cut to 13.875 in, Fi's published cutout, under the 15.5 in frame. The rear panel rakes 20 degrees, so the cavity deepens from 10.17 in at the top to 16.72 in at the base, and the 7.375 in motor clears it with 2.68 in to spare. Fi prints no bolt circle for the Alpha 15, so the baffle ships undrilled with a threaded insert kit and stainless machine screws: set the driver in the recess, mark its holes, drill, press the inserts and bolt it down.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eWhat the Numbers Rest On\u003c\/h2\u003e\n\u003cdiv class=\"po-grid\"\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eLangboard Elite MDF\u003c\/h4\u003e\n\u003cp\u003ePremium 3\/4 in MDF throughout.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eV-Groove and Dado Joinery\u003c\/h4\u003e\n\u003cp\u003eCNC cut V-grooves at every panel intersection, sides and brace seated in dados.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eDouble-Layer 1.5\" Front Baffle\u003c\/h4\u003e\n\u003cp\u003eTwo bonded 3\/4 in MDF sheets at the driver face, the outer layer machined as a flush recess.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eFi's Published Parameters\u003c\/h4\u003e\n\u003cp\u003eFs 34.7 Hz, Qts 0.52, Qes 0.56, Qms 8.10, Vas 61.00 L, Sd 810 cm2, Cms 0.0663 mm\/N, Mms 326 g, Bl 10.0 \/ 14.1 \/ 20.2 N\/A (S1 \/ S2 \/ S4), Re 0.8 \/ 1.6 \/ 3.3 ohms, sensitivity 88.5 dB 1W\/1m.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eWiring the Fi Car Audio Alpha 15 to Your Amplifier\u003c\/h2\u003e\n\u003cp\u003eThe single coil comes as S1, S2 or S4: 1, 2 or 4 ohms, wired straight to the amplifier. Confirm the final load against your amplifier's minimum stable impedance before powering the system.\u003c\/p\u003e\n\u003cp\u003ePower handling is 1000 watts RMS per driver. Aim for roughly 700 to 1000 watts at the impedance you wire.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eBuilt in Tennessee, Backed by Audio Intensity\u003c\/h2\u003e\n\u003cp\u003eCut and assembled in Tullahoma, Tennessee on our own CNC equipment. Finished in plush black carpet with the gloss black acrylic baffle insert, one pre-wired terminal cup, 12 gauge OFC to the driver position. Polyfill wall lining installed. Threaded insert kit and stainless machine screws in the box. 1 year limited warranty. Enclosure only, the driver is purchased separately. Call or text 931-563-5151.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-cta\"\u003e\n\u003ch2\u003eFi Car Audio Alpha 15: Cut for the Driver\u003c\/h2\u003e\n\u003cp\u003e2.54 cubic feet net at Qtc 0.707, F3 47.2 Hz, cut direct fit and built to order in Tennessee.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Black","offer_id":47368499888217,"sku":"PO 15-S W FI ALPHA BB","price":369.99,"currency_code":"USD","in_stock":true},{"title":"None","offer_id":47368499920985,"sku":"PO 15-S W FI ALPHA B","price":349.99,"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_c0373c71-f8c8-4687-81d3-577b8a15b16c.jpg?v=1790975096"},{"product_id":"performance-optimized-wedge-sealed-dual-15-enclosure-fi-car-audio-alpha-15","title":"Performance Optimized Wedge Sealed Dual 15\" Enclosure | Fi Car Audio Alpha 15","description":"\u003cdiv class=\"po-wrap\"\u003e\n\u003cstyle\u003e\n.po-wrap{font-family:'Helvetica Neue',Arial,sans-serif;line-height:1.8;color:#1e293b;max-width:1200px;margin:0 auto;background:#fff}\n.po-hero{background:linear-gradient(135deg,#0f172a 0%,#8b5a2b 100%);padding:60px 40px;text-align:center;color:#fff}\n.po-hero .po-title{font-size:2.6em;font-weight:800;text-transform:uppercase;letter-spacing:2px;margin:0 0 10px 0;color:#fff}\n.po-hero .po-subtitle{font-size:1.2em;font-weight:300;opacity:.9;margin:0 0 30px 0}\n.po-badges{display:flex;justify-content:center;flex-wrap:wrap;gap:12px;margin-top:20px}\n.po-badge{background:rgba(184,115,51,.2);border:1px solid #b87333;color:#d99058;padding:8px 20px;border-radius:20px;font-size:.9em;font-weight:600;letter-spacing:.5px}\n.po-section{padding:50px 40px;border-bottom:1px solid #e2e8f0;background:#fff}\n.po-section:nth-child(even){background:#fef3e7}\n.po-section h2{color:#8b5a2b;font-size:2em;font-weight:700;margin:0 0 20px 0;padding-bottom:12px;border-bottom:3px solid #b87333}\n.po-section h3{color:#0f172a;font-size:1.4em;font-weight:600;margin:30px 0 15px 0}\n.po-section p{font-size:1.05em;color:#334155;margin-bottom:18px}\n.po-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:24px;margin:30px 0}\n.po-card{background:#fff;border:1px solid #e2e8f0;border-top:4px solid #b87333;padding:25px;border-radius:4px}\n.po-card h4{color:#8b5a2b;font-size:1.15em;font-weight:700;margin:0 0 12px 0;text-transform:uppercase;letter-spacing:1px}\n.po-card p{font-size:.98em;color:#475569;margin:0}\n.po-highlight{background:#fef3e7;border-left:4px solid #b87333;padding:25px 30px;margin:30px 0;border-radius:4px}\n.po-highlight p{color:#1e293b;margin:0;font-size:1.05em}\n.po-cta{background:linear-gradient(135deg,#0f172a 0%,#8b5a2b 100%);padding:60px 40px;text-align:center;color:#fff}\n.po-cta h2{font-size:2.2em;font-weight:700;margin:0 0 20px 0;color:#fff;border:none;padding:0}\n.po-cta p{font-size:1.15em;opacity:.92;max-width:800px;margin:0 auto 20px auto;color:#fff}\n@media (max-width:768px){.po-hero{padding:40px 20px}.po-hero .po-title{font-size:1.8em}.po-section{padding:30px 20px}.po-section h2{font-size:1.6em}.po-grid{grid-template-columns:1fr}.po-cta{padding:40px 20px}.po-cta h2{font-size:1.6em}}\n\u003c\/style\u003e\n\u003cdiv class=\"po-hero\"\u003e\n\u003cp class=\"po-title\"\u003ePerformance Optimized Wedge | Dual Fi Car Audio Alpha 15\u003c\/p\u003e\n\u003cp class=\"po-subtitle\"\u003eDual 15\" Sealed Wedge Enclosure | Rear-Firing Trunk-Load Design\u003c\/p\u003e\n\u003cdiv class=\"po-badges\"\u003e\n\u003cspan class=\"po-badge\"\u003e1.80 ft3 Net per Chamber\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003e3.97 ft3 Gross\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eQtc 0.77\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eTwo Separate Chambers\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003e36.00\" x 18\" x 12.13\/18.68\"\u003c\/span\u003e\u003cspan class=\"po-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eA Pair of Fi Car Audio Alpha 15 in a Sealed Wedge\u003c\/h2\u003e\n\u003cp\u003eThe Alpha 15 is the 15 inch from Fi Car Audio's Alpha v1 line: 1000 watts RMS, 17 mm of one-way excursion on 810 square centimeters of cone, and 7.375 inches of mounting depth. Every figure comes from the Thiele-Small and technical tables Fi prints on its Alpha Series product page, including the 0.14 cubic foot driver displacement, and the parameters check against each other: the printed Qts reproduces from Qes and Qms, and Fi's moving mass agrees with its Fs, Vas and cone area.\u003c\/p\u003e\n\u003cdiv class=\"po-highlight\"\u003e\u003cp\u003e1.80 cubic feet net per chamber is Fi's own minimum recommended sealed volume for the Alpha 15. On Fi's figures, Fs 34.7 Hz, Qts 0.52 and Vas 61.00 liters, that is Qtc 0.771 with half power at 47.5 Hz. Fi publishes one parameter set for the Alpha 15 that covers the S1, S2 and S4 single coil versions, so one alignment serves all three. Fi's own recommended sealed range for the Alpha 15 is 1.8 to 3 cubic feet, which reads Qtc 0.77 to 0.68.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eTwo Fully Separate Chambers\u003c\/h2\u003e\n\u003cp\u003eA bonded full-height 3\/4 inch MDF divider splits the cabinet into two sealed chambers of 1.80 cubic feet net each, so every driver sees exactly the airspace printed on this page. Two drivers sharing one volume load each other; the divider removes that, and each chamber carries its own polyfill.\u003c\/p\u003e\n\u003cp\u003eThe cabinet is 36.00 inches wide, 18 tall, 12.13 inches deep at the top and 18.68 at the base. One shared side-mounted terminal cup feeds both driver positions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eTrunk-Load Wedge Design Explained\u003c\/h2\u003e\n\u003cp\u003eThe drivers mount on the vertical trunk-lid-side face and fire rearward into the trunk cavity.\u003c\/p\u003e\n\u003cdiv class=\"po-grid\"\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eSeat-Side Face Matches Seat Lean\u003c\/h4\u003e\n\u003cp\u003eAngled face matches the roughly 20 degree factory seat lean.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eTrunk-Lid-Side Face Fires the Woofer\u003c\/h4\u003e\n\u003cp\u003eVertical baffle, cone firing rearward into the trunk cavity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eTrunk Cavity Loading\u003c\/h4\u003e\n\u003cp\u003eThe trunk acts as an acoustic extension for a smoother presentation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003ePreserves Trunk Cargo Space\u003c\/h4\u003e\n\u003cp\u003eThe wedge tucks against the seat back and the space in front stays usable.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eEngineered for a pair of Fi Car Audio Alpha 15\u003c\/h2\u003e\n\u003cp\u003eHalf power lands at 47.5 Hz anechoic, before any cabin gain. Above Qtc 0.707 the response carries a small lift near 51 Hz before the rolloff, and F3 sits below fc. Fi publishes the driver displacement, 0.14 cubic feet, and it is taken out of the net figure.\u003c\/p\u003e\n\u003ch3\u003eAlignment Numbers (Per Chamber)\u003c\/h3\u003e\n\u003ctable class=\"df-tier\"\u003e\n\u003ctr\u003e\n\u003cth\u003eDriver (per chamber)\u003c\/th\u003e\n\u003cth\u003eSystem Qtc\u003c\/th\u003e\n\u003cth\u003efc\u003c\/th\u003e\n\u003cth\u003eF3\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAlpha 15 S1, S2 or S4\u003c\/td\u003e\n\u003ctd\u003eQtc 0.771\u003c\/td\u003e\n\u003ctd\u003e51.4 Hz\u003c\/td\u003e\n\u003ctd\u003e47.5 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch3\u003eMounting Geometry\u003c\/h3\u003e\n\u003cp\u003eThe baffle is cut to 13.875 in, Fi's published cutout, under the 15.5 in frame. The rear panel rakes 20 degrees, so the cavity deepens from 12.13 in at the top to 18.68 in at the base, and the 7.375 in motor clears it with 4.65 in to spare. Fi prints no bolt circle for the Alpha 15, so the baffle ships undrilled with a threaded insert kit and stainless machine screws: set the driver in the recess, mark its holes, drill, press the inserts and bolt it down.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eWhat the Numbers Rest On\u003c\/h2\u003e\n\u003cdiv class=\"po-grid\"\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eLangboard Elite MDF\u003c\/h4\u003e\n\u003cp\u003ePremium 3\/4 in MDF throughout.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eV-Groove and Dado Joinery\u003c\/h4\u003e\n\u003cp\u003eCNC cut V-grooves at every panel intersection, sides and divider seated in dados.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eDouble-Layer 1.5\" Front Baffle\u003c\/h4\u003e\n\u003cp\u003eTwo bonded 3\/4 in MDF sheets at the driver face, the outer layer machined as a flush recess.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-card\"\u003e\n\u003ch4\u003eFi's Published Parameters\u003c\/h4\u003e\n\u003cp\u003eFs 34.7 Hz, Qts 0.52, Qes 0.56, Qms 8.10, Vas 61.00 L, Sd 810 cm2, Cms 0.0663 mm\/N, Mms 326 g, Bl 10.0 \/ 14.1 \/ 20.2 N\/A (S1 \/ S2 \/ S4), Re 0.8 \/ 1.6 \/ 3.3 ohms, sensitivity 88.5 dB 1W\/1m.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eWiring a pair of Fi Car Audio Alpha 15 to Your Amplifier\u003c\/h2\u003e\n\u003cp\u003eA pair lands on 0.5 ohm parallel or 2 ohms series with S1 coils, 1 ohm parallel or 4 ohms series with S2, and 2 ohms parallel or 8 ohms series with S4. Anything under 1 ohm, and many amplifiers at 1 ohm, is outside what the amplifier is built for; series wiring is the safe default. Confirm the final load against your amplifier's minimum stable impedance before powering the system.\u003c\/p\u003e\n\u003cp\u003ePower handling is 1000 watts RMS per driver, 2000 across the pair. Aim for roughly 700 to 1000 watts per driver at the impedance you wire.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-section\"\u003e\n\u003ch2\u003eBuilt in Tennessee, Backed by Audio Intensity\u003c\/h2\u003e\n\u003cp\u003eCut and assembled in Tullahoma, Tennessee on our own CNC equipment. Finished in plush black carpet with the gloss black acrylic baffle insert, one shared pre-wired terminal cup, 12 gauge OFC to both driver positions. Polyfill wall lining installed. Threaded insert kit and stainless machine screws in the box. 1 year limited warranty. Enclosure only, the drivers are purchased separately. Call or text 931-563-5151.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"po-cta\"\u003e\n\u003ch2\u003eDual Fi Car Audio Alpha 15: Cut for the Driver\u003c\/h2\u003e\n\u003cp\u003e1.80 cubic feet net per chamber at Qtc 0.771, F3 47.5 Hz, cut direct fit and built to order in Tennessee.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Black","offer_id":47368499986521,"sku":"PO 15D-S W FI ALPHA BB","price":519.99,"currency_code":"USD","in_stock":true},{"title":"None","offer_id":47368500019289,"sku":"PO 15D-S W FI ALPHA B","price":499.99,"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_64d932a3-af6f-41cf-8f3f-a52d58125f41.jpg?v=1790975107"}],"url":"https:\/\/audiointensity.com\/collections\/fi-car-audio-subwoofer-box.oembed","provider":"Audio Intensity","version":"1.0","type":"link"}