{"title":"Stereo Integrity Subwoofer Boxes and Enclosures","description":"\u003cdiv class=\"ai-collection-block\"\u003e\n\n\u003ch2\u003eSealed, Because the SQL Wants Sealed\u003c\/h2\u003e\n\n\u003cp\u003eTwo enclosures cut for the Stereo Integrity 12 inch SQL Series. A single at $279.99 and a dual at $359.99, both sealed, both Performance Optimized.\u003c\/p\u003e\n\n\u003cp\u003eSealed is not a default here, it is the right answer for this driver. The SQL is built for sound quality rather than raw output, and its parameters put it clearly in sealed territory. A sealed cabinet gives you the shallower rolloff and tighter transient response that the driver was designed around. Porting it would buy output the SQL was never trying to win and cost you the control that is the reason to own one.\u003c\/p\u003e\n\n\u003ch2\u003eAcrylic Insert Options\u003c\/h2\u003e\n\n\u003cp\u003eBoth enclosures come with a choice of acrylic baffle insert in black, blue, red or white, or without an insert at $20 less. The insert is cut on our laser in house and sits proud of the baffle. It is cosmetic rather than acoustic, so pick it on looks alone and do not expect it to change anything you can hear.\u003c\/p\u003e\n\n\u003ch2\u003eSingle or Dual\u003c\/h2\u003e\n\n\u003cp\u003eThe dual shares one cabinet between two drivers. Before you commit, work out the final impedance your wiring produces and confirm your amplifier is stable at it. Two dual voice coil drivers give you several wiring options and not all of them suit every monoblock. Our \u003ca href=\"https:\/\/audiointensity.com\/pages\/subwoofer-wiring-diagram-generator\"\u003ewiring diagram generator\u003c\/a\u003e will show you the options and the resulting load.\u003c\/p\u003e\n\n\u003cp\u003eWe build enclosures for Stereo Integrity but do not stock the drivers. You supply the sub, we supply the cabinet.\u003c\/p\u003e\n\n\u003caside class=\"ai-callout-cta\"\u003e\n\u003cp class=\"ai-callout-label\"\u003eDifferent SI Driver?\u003c\/p\u003e\n\u003cp\u003eOther SQL sizes and the rest of the Stereo Integrity range are buildable. Tell us the model and the space you have.\u003c\/p\u003e\n\u003cp\u003e\u003cspan class=\"ai-contact-phone\"\u003e707-999-3071\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 3\/4 inch MDF, CNC cut on ShopSabre routers in Tullahoma, Tennessee. Internally braced, prewired to a Proline X ABS and carbon fiber terminal cup with stainless steel hardware, and shipped with polyfill installed. Performance Optimized enclosures carry a 1 year limited warranty on craftsmanship and materials.\u003c\/p\u003e\n\n\u003cp\u003eNet volume comes from the SQL published Thiele Small parameters. If you want to see the alignment math yourself, run it through our \u003ca href=\"https:\/\/audiointensity.com\/pages\/sealed-box-calculator\"\u003esealed box calculator\u003c\/a\u003e for Qtc, fc and F3.\u003c\/p\u003e\n\n\u003cp\u003eBrowse the wider range at the \u003ca href=\"https:\/\/audiointensity.com\/pages\/shop-subwoofer-enclosures\"\u003eenclosure finder\u003c\/a\u003e, or look at \u003ca href=\"https:\/\/audiointensity.com\/collections\/sealed-subwoofer-boxes\"\u003esealed enclosures\u003c\/a\u003e and \u003ca href=\"https:\/\/audiointensity.com\/collections\/12-inch-subwoofer-box\"\u003e12 inch enclosures\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Stereo Integrity Enclosure Questions\u003c\/h2\u003e\n\n\u003ch3\u003eDo you sell Stereo Integrity subwoofers?\u003c\/h3\u003e\n\u003cp\u003eNo. We build enclosures for them but do not stock the drivers.\u003c\/p\u003e\n\n\u003ch3\u003eWhy sealed rather than ported?\u003c\/h3\u003e\n\u003cp\u003eThe SQL is a sound quality driver and its parameters suit a sealed alignment. Sealed gives a shallower rolloff and better transient control, which is the whole point of that driver. Porting it would chase output it was not built to win.\u003c\/p\u003e\n\n\u003ch3\u003eDoes the acrylic insert change the sound?\u003c\/h3\u003e\n\u003cp\u003eNo. It is a cosmetic baffle insert cut on our laser. Choose it on appearance. The version without an insert costs $20 less and performs identically.\u003c\/p\u003e\n\n\u003ch3\u003eWhat impedance will the dual enclosure present?\u003c\/h3\u003e\n\u003cp\u003eThat depends on your drivers and how you wire them. Two dual voice coil subwoofers give you several options. Run your configuration through our wiring diagram generator and confirm your amplifier is stable at the resulting load before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eCan you build for other SQL sizes?\u003c\/h3\u003e\n\u003cp\u003eYes, and for the rest of the Stereo Integrity range. Give us the exact model, whether you want sealed or ported, and your maximum external dimensions.\u003c\/p\u003e\n\n\u003ch3\u003eWhat is the warranty?\u003c\/h3\u003e\n\u003cp\u003ePerformance Optimized enclosures carry a 1 year limited warranty on craftsmanship and materials. Micro Series and Professional Series carry 2 years. The driver carries its own manufacturer warranty separately.\u003c\/p\u003e\n\n\u003c\/div\u003e","products":[{"product_id":"performance-optimized-sealed-dual-12-enclosure-stereo-integrity-12-sql-series","title":"Proline X PO12D-S SI | Dual 12\" Sealed Subwoofer Enclosure | Built for Stereo Integrity SQL","description":"\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: #ffffff; }\n  .po-hero { background: linear-gradient(135deg, #0f172a 0%, #0e7490 100%); padding: 60px 40px; text-align: center; color: white; }\n  .po-hero .po-title { font-size: 2.6em; font-weight: 800; text-transform: uppercase; letter-spacing: 2px; margin: 0 0 10px 0; color: white; }\n  .po-hero .po-subtitle { font-size: 1.2em; font-weight: 300; opacity: 0.9; 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(6, 182, 212, 0.2); border: 1px solid #06b6d4; color: #67e8f9; padding: 8px 20px; border-radius: 20px; font-size: 0.9em; font-weight: 600; letter-spacing: 0.5px; }\n  .po-section { padding: 50px 40px; border-bottom: 1px solid #e2e8f0; background: #ffffff; }\n  .po-section:nth-child(even) { background: #f0f9ff; }\n  .po-section h2 { color: #0e7490; font-size: 2em; font-weight: 700; margin: 0 0 20px 0; padding-bottom: 12px; border-bottom: 3px solid #06b6d4; }\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: #ffffff; border: 1px solid #e2e8f0; border-top: 4px solid #06b6d4; padding: 25px; border-radius: 4px; }\n  .po-card h4 { color: #0e7490; font-size: 1.15em; font-weight: 700; margin: 0 0 12px 0; text-transform: uppercase; letter-spacing: 1px; }\n  .po-card p { font-size: 0.98em; color: #475569; margin: 0; }\n  .po-highlight { background: #f0f9ff; border-left: 4px solid #06b6d4; 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%, #0e7490 100%); padding: 60px 40px; text-align: center; color: white; }\n  .po-cta h2 { font-size: 2.2em; font-weight: 700; margin: 0 0 20px 0; color: white; border: none; padding: 0; }\n  .po-cta p { font-size: 1.15em; opacity: 0.92; max-width: 800px; margin: 0 auto 20px auto; color: white; }\n  @media (max-width: 768px) {\n    .po-hero { padding: 40px 20px; }\n    .po-hero .po-title { font-size: 1.8em; }\n    .po-section { padding: 30px 20px; }\n    .po-section h2 { font-size: 1.6em; }\n    .po-grid { grid-template-columns: 1fr; }\n    .po-cta { padding: 40px 20px; }\n    .po-cta h2 { font-size: 1.6em; }\n  }\n\u003c\/style\u003e\n\n\u003cdiv class=\"po-wrap\"\u003e\n\n  \u003cdiv class=\"po-hero\"\u003e\n    \u003cp class=\"po-title\"\u003ePerformance Optimized | Dual Stereo Integrity SQL 12\u003c\/p\u003e\n    \u003cp class=\"po-subtitle\"\u003eDual 12\" Sealed Enclosure | Isolated Chambers | Dual Mounting Face for the SQL 12 Series 2\u003c\/p\u003e\n    \u003cdiv class=\"po-badges\"\u003e\n      \u003cspan class=\"po-badge\"\u003e2.0 ft³ Net Total\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003eIsolated Chambers\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003e1.0 ft³ Per Chamber\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003e31\" × 15\" × 13.625\"\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003eDouble Baffle\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003eV-Groove \/ Dado\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eTwo Stereo Integrity SQL 12s, Each in Their Own Engineered Chamber\u003c\/h2\u003e\n    \u003cp\u003eThe Performance Optimized Dual Sealed 12 for the Stereo Integrity SQL 12 is a fully chambered sealed enclosure engineered around a pair of SQL 12 Series 2 subwoofers. Two isolated 1.0 cubic foot chambers, separated by a center divider, each tuned to the SQL 12's published Thiele-Small parameters. Dual mounting face design gives each driver its own dedicated baffle. No shared airspace, no acoustic crosstalk between drivers, no compromise from doubling up in a common chamber.\u003c\/p\u003e\n    \u003cp\u003eThis is not the same construction as our common-chamber PO duals. The SQL 12 is a serious high-power driver — 1000 watts RMS per unit, 26mm one-way linear Xmax, and enough motor force to move meaningful air. At those power and excursion levels, isolated chambers stop being nice-to-have and become the correct engineering answer. Each SQL 12 operates in its own dedicated acoustic environment, unaffected by what the other driver is doing at any given moment.\u003c\/p\u003e\n    \u003cdiv class=\"po-highlight\"\u003e\n      \u003cp\u003eEach SQL 12 gets its own sealed 1.0 cubic foot chamber — the maximum sealed volume Stereo Integrity specifies for the SQL 12 Series 2. The chambered design means each driver operates as if it were in its own dedicated single enclosure, with a center divider that also serves as structural bracing.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eWhy Isolated Chambers Matter at This Power Level\u003c\/h2\u003e\n    \u003cp\u003eFor lower-power dual subwoofer systems in the 300-500 watt per driver range, a common chamber works fine. Matched driver pairs load symmetrically, and shared airspace introduces minimal interaction. At the SQL 12's 1000 watt RMS per driver rating, the calculation changes. Higher power means more cone excursion, more thermal load, and more asymmetric behavior between the two drivers as they respond to different thermal and mechanical states in real time. Isolated chambers eliminate that variable entirely.\u003c\/p\u003e\n    \u003cdiv class=\"po-grid\"\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003eSymmetric Loading Under Real Power\u003c\/h4\u003e\n        \u003cp\u003eEach SQL 12 operates against its own dedicated 1.0 cubic foot airspace. If one driver's voice coil resistance rises from heat faster than the other, or if one driver breaks in at a slightly different rate, the pair still performs consistently because they aren't coupled through shared air.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003eForce Cancellation Benefits\u003c\/h4\u003e\n        \u003cp\u003eThe dual mounting face design creates opposing forces that partially cancel through the cabinet structure. Less mechanical energy transferred to the vehicle chassis, less rattle in trim panels, and cleaner perceived output because the cabinet itself is doing less unwanted work.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003eStructural Rigidity\u003c\/h4\u003e\n        \u003cp\u003eThe center divider acts as a full-length brace in addition to its acoustic role. The 31\" cabinet width is split into two 15.5\" panel sections structurally, dramatically reducing panel flex compared to an unbraced wide interior at the power levels the SQL 12 delivers.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003ePredictable Behavior at Full Excursion\u003c\/h4\u003e\n        \u003cp\u003eThe SQL 12's 26mm one-way Xmax means significant air displacement per stroke. Isolated chambers guarantee each driver's air spring stays consistent through the full excursion range, without pressure variations from the second driver influencing the first.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eEngineered Around the SQL 12's Parameters\u003c\/h2\u003e\n    \u003cp\u003eStereo Integrity specifies the SQL 12 Series 2 for sealed enclosures between 0.65 and 1.0 cubic feet per driver. The Performance Optimized Dual Sealed 12 delivers 1.0 cubic foot per chamber — the upper end of SI's specified range, where the SQL's deep low-end extension characteristics fully develop. In a properly sized cabinet, the SQL 12 plays down to F3 points in single-digit territory, delivering the low-frequency response that makes SI's SQL series unmatched at its price point.\u003c\/p\u003e\n    \u003ch3\u003eVolume Selection\u003c\/h3\u003e\n    \u003cp\u003e1.0 cubic foot per chamber is the maximum of SI's recommended sealed volume range. Smaller volumes tighten Qtc and lose some low-end extension. Larger volumes fall outside SI's specification and compromise transient control. 1.0 cubic foot per driver is where the SQL 12 delivers on its full low-end capability while staying inside the driver's engineered operating window.\u003c\/p\u003e\n    \u003ch3\u003eMounting Geometry\u003c\/h3\u003e\n    \u003cp\u003eBoth baffles are cut to the SQL 12's exact 11.33\" cutout specification and doubled to 1.5\" total thickness at the mounting position. The SQL 12's 7\" mounting depth leaves comfortable internal clearance inside the 13.625\" deep cabinet. Each driver has its own dedicated mounting face — a true dual-face design that separates the two drivers acoustically and mechanically, with 8\/32 threaded inserts pressed into the doubled baffle stock for secure, full-depth mounting.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003ePerformance Series Construction, Driver-Specific Tuning\u003c\/h2\u003e\n    \u003cdiv class=\"po-grid\"\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003eDouble Baffle Mounting Faces\u003c\/h4\u003e\n        \u003cp\u003eEach of the two mounting faces uses a doubled 1.5\" total baffle thickness — two layers of 3\/4\" Langboard Elite MDF bonded together at the driver mounting position. Doubled baffle stock resists baffle flex and mounting screw pullout at the power levels the SQL 12 delivers.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003e8\/32 Threaded Inserts Into Double Baffle\u003c\/h4\u003e\n        \u003cp\u003eBoth baffles use 8\/32 threaded inserts pressed into the doubled 1.5\" MDF backside, providing full-depth thread engagement for the supplied stainless steel mounting screws. No stripped pilot holes, no MDF damage from drywall screws, and secure retention at high excursion levels.\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 let the cabinet fold into shape with maximum glue surface. Dado joints lock the doubled baffles, rear panel, and center divider into the side walls — no fasteners visible from outside, no exposed end grain at joints.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003ePre-Wired Terminal Cups (×2)\u003c\/h4\u003e\n        \u003cp\u003eOne Proline X ABS\/carbon fiber composite terminal cup per chamber, each pre-wired with 12-gauge OFC. Wire each driver to its own amp channel for maximum control, or jumper the cups externally for a single-channel pair.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cp\u003eEvery panel is cut on ShopSabre CNC routers in our Tullahoma, TN facility. The center divider is dadoed into the top, bottom, and rear panels for maximum mechanical lock — not just glued in. Both mounting baffles are doubled to 1.5\" total thickness at the mounting positions. Internal volume is verified per chamber on every unit.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eCustomize Your Build\u003c\/h2\u003e\n    \u003ch3\u003eCarpet Finish\u003c\/h3\u003e\n    \u003cp\u003e\u003cstrong\u003eDark Gray Trunkliner\u003c\/strong\u003e is the standard durable wrap, matched to most factory trunk and cargo-area carpet tones. \u003cstrong\u003ePlush Black\u003c\/strong\u003e (+$10) is a deeper, more luxurious nap that pairs well with blacked-out interiors and show builds.\u003c\/p\u003e\n    \u003ch3\u003eAcrylic Insert Color\u003c\/h3\u003e\n    \u003cp\u003eChoose \u003cstrong\u003eBlack, Blue, Red, or White\u003c\/strong\u003e for the baffle inserts to match your build. Or skip the inserts entirely (-$40) for a clean, understated look. The inserts are purely cosmetic — performance is identical across colors.\u003c\/p\u003e\n    \u003ch3\u003eBox-Only or Loaded Pair\u003c\/h3\u003e\n    \u003cp\u003eAdd a matched pair of Stereo Integrity SQL 12 Series 2 drivers directly to your order in \u003cstrong\u003eDual 2-ohm or Dual 4-ohm\u003c\/strong\u003e and \u003cstrong\u003ePaper or Carbon Fiber\u003c\/strong\u003e dust cap configurations. Already own your SQL 12s? Order the enclosure box-only and drop in the drivers you have.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eWiring Two SQL 12s to Your Amplifier\u003c\/h2\u003e\n    \u003cp\u003eEach chamber has its own dedicated terminal cup, pre-wired with 12-gauge OFC. The two cups can be jumpered externally for a single-amp installation, or wired independently for dual monoblock or multi-channel amplifier setups.\u003c\/p\u003e\n    \u003ch3\u003eTwo Dual 2-Ohm SQL 12s\u003c\/h3\u003e\n    \u003cp\u003eEach driver's coils in parallel = 1 ohm per driver. Two 1-ohm drivers in parallel = 0.5 ohm combined (most monoblocks won't handle this — verify your amp). Two 1-ohm drivers in series = 2 ohms combined. Each driver on its own monoblock at 1 ohm gives you the cleanest high-power setup.\u003c\/p\u003e\n    \u003ch3\u003eTwo Dual 4-Ohm SQL 12s\u003c\/h3\u003e\n    \u003cp\u003eEach driver's coils in parallel = 2 ohms per driver. Two 2-ohm drivers in parallel = 1 ohm combined. Two 2-ohm drivers in series = 4 ohms combined. Dual 4-ohm is the more flexible option for most amplifier setups at these power levels.\u003c\/p\u003e\n    \u003cp\u003eThe SQL 12 pair is rated for 2000 watts RMS combined. Aim for a clean, well-regulated amplifier or amplifier pair delivering 1500 to 2000 watts total at your chosen impedance. At this power level, amplifier quality matters more than headline numbers — regulated power supply, low THD, and honest RMS ratings.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eBuilt in Tennessee, Backed by Audio Intensity\u003c\/h2\u003e\n    \u003cp\u003eEvery Performance Optimized enclosure is CNC-cut, assembled, and finished in our Tullahoma, TN facility. Components are pulled from inventory after your order is placed, then bonded and wrapped — a 2 to 5 business day assembly window before the box ships. No pre-built inventory sitting in warehouses, warping in storage. Each unit is built to order.\u003c\/p\u003e\n    \u003cp\u003eBacked by a 1-year limited warranty against structural failure and hardware defects. Questions on fitment, wiring, or amplifier pairing? \u003ca href=\"\/pages\/contact-us\"\u003eContact us\u003c\/a\u003e — we install this gear ourselves, in our own vehicles.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-cta\"\u003e\n    \u003ch2\u003eTwo SQL 12s, Engineered Correctly\u003c\/h2\u003e\n    \u003cp\u003eIsolated chamber design, dual mounting face, driver-specific 1.0 cubic foot chambers, and Performance Series construction built for the power levels the SQL 12 delivers. The correct cabinet for a serious pair of SIs.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Plush Black \/ Black","offer_id":43786903289945,"sku":"PO12D-S SI BB","price":389.99,"currency_code":"USD","in_stock":true},{"title":"Plush Black \/ Blue","offer_id":43786903322713,"sku":"PO12D-S SI BBL","price":389.99,"currency_code":"USD","in_stock":true},{"title":"Plush Black \/ Red","offer_id":43786903355481,"sku":"PO12D-S SI BR","price":389.99,"currency_code":"USD","in_stock":true},{"title":"Plush Black \/ White","offer_id":43786903388249,"sku":"PO12D-S SI BW","price":389.99,"currency_code":"USD","in_stock":true},{"title":"Plush Black \/ None","offer_id":43786903421017,"sku":"PO12D-S SI B","price":359.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0689\/1389\/files\/performance-optimized-sealed-dual-12-enclosure-stereo-integrity-12-sql-seriessubwoofer-enclosuresproline-x-3250530.png?v=1784976188"},{"product_id":"performance-optimized-sealed-12-enclosure-stereo-integrity-12-sql-series","title":"Proline X PO12-S SI | Single 12\" Sealed Subwoofer Enclosure | Built for Stereo Integrity SQL","description":"\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: #ffffff; }\n  .po-hero { background: linear-gradient(135deg, #0f172a 0%, #0e7490 100%); padding: 60px 40px; text-align: center; color: white; }\n  .po-hero .po-title { font-size: 2.6em; font-weight: 800; text-transform: uppercase; letter-spacing: 2px; margin: 0 0 10px 0; color: white; }\n  .po-hero .po-subtitle { font-size: 1.2em; font-weight: 300; opacity: 0.9; 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(6, 182, 212, 0.2); border: 1px solid #06b6d4; color: #67e8f9; padding: 8px 20px; border-radius: 20px; font-size: 0.9em; font-weight: 600; letter-spacing: 0.5px; }\n  .po-section { padding: 50px 40px; border-bottom: 1px solid #e2e8f0; background: #ffffff; }\n  .po-section:nth-child(even) { background: #f0f9ff; }\n  .po-section h2 { color: #0e7490; font-size: 2em; font-weight: 700; margin: 0 0 20px 0; 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font-weight: 700; margin: 0 0 20px 0; color: white; border: none; padding: 0; }\n  .po-cta p { font-size: 1.15em; opacity: 0.92; max-width: 800px; margin: 0 auto 20px auto; color: white; }\n  @media (max-width: 768px) {\n    .po-hero { padding: 40px 20px; }\n    .po-hero .po-title { font-size: 1.8em; }\n    .po-section { padding: 30px 20px; }\n    .po-section h2 { font-size: 1.6em; }\n    .po-grid { grid-template-columns: 1fr; }\n    .po-cta { padding: 40px 20px; }\n    .po-cta h2 { font-size: 1.6em; }\n  }\n\u003c\/style\u003e\n\n\u003cdiv class=\"po-wrap\"\u003e\n\n  \u003cdiv class=\"po-hero\"\u003e\n    \u003cp class=\"po-title\"\u003ePerformance Optimized | Stereo Integrity SQL 12\u003c\/p\u003e\n    \u003cp class=\"po-subtitle\"\u003eSingle 12\" Sealed Enclosure | Driver-Specific for the SQL 12 Series 2\u003c\/p\u003e\n    \u003cdiv class=\"po-badges\"\u003e\n      \u003cspan class=\"po-badge\"\u003e1.0 ft³ Net\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003eDriver-Specific\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003eDouble Baffle\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003e20\" × 15\" × 13.625\"\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003eV-Groove \/ Dado\u003c\/span\u003e\n      \u003cspan class=\"po-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eThe Stereo Integrity SQL 12 Deserves a Box Built for It\u003c\/h2\u003e\n    \u003cp\u003eThe Stereo Integrity SQL 12 Series 2 is a serious high-power driver — 1000 watts RMS, 26mm one-way linear Xmax, 2.75\" copper voice coil on a split black anodized aluminum former, and enough motor force to move meaningful air in a properly sized sealed cabinet. Drop it in a generic box and you'll get loud bass. Drop it in a cabinet engineered around SI's published Thiele-Small parameters, with construction sized for the power level the SQL 12 delivers, and you'll hear what Nick Sowa's team built this driver to do.\u003c\/p\u003e\n    \u003cp\u003eThe Performance Optimized Sealed 12 for Stereo Integrity SQL 12 is that cabinet. Internal volume, baffle thickness, mounting hardware, and construction methods are all chosen to extract the SQL 12's full mechanical and acoustic potential — and to hold together as a rigid structure at the power levels this driver is capable of.\u003c\/p\u003e\n    \u003cdiv class=\"po-highlight\"\u003e\n      \u003cp\u003eThis enclosure is engineered specifically around the Stereo Integrity SQL 12 Series 2. The 1.0 cubic foot net volume matches the maximum sealed volume SI specifies for the SQL 12 — where the driver's deep low-end extension fully develops with F3 points in single-digit territory.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eWhy Performance Optimized Sits Where It Does\u003c\/h2\u003e\n    \u003cp\u003eThe Performance Optimized line is the bridge between our standard Performance Series and our top-tier Professional Series. Same Performance-tier construction quality — Langboard Elite MDF, V-groove and dado joinery, ShopSabre CNC routing — but the geometry of every panel is cut around one specific driver instead of a class of drivers. For the SQL 12 specifically, that also means doubled baffle stock at the mounting position to handle the driver's power capability.\u003c\/p\u003e\n    \u003cdiv class=\"po-grid\"\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003evs Performance Series\u003c\/h4\u003e\n        \u003cp\u003eStandard Performance Series boxes (P6 through P15) are built for universal driver fitment within a size class. Great if you want flexibility across multiple driver options. Performance Optimized takes the same construction foundation and locks the airspace and hardware to one specific driver.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003evs Professional Series\u003c\/h4\u003e\n        \u003cp\u003eProfessional Series uses extensive multi-layer baffles, triple-stacked construction, and a 2-year warranty for the most demanding builds. Performance Optimized delivers driver-specific engineering with double baffle construction at a more accessible price point with a 1-year warranty.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eEngineered Around the SQL 12's Parameters\u003c\/h2\u003e\n    \u003cp\u003eStereo Integrity specifies the SQL 12 Series 2 for sealed enclosures between 0.65 and 1.0 cubic feet. The Performance Optimized Sealed 12 delivers 1.0 cubic feet net — the maximum of SI's specified range, where the SQL's deep low-end extension characteristics fully develop. In this cabinet, the SQL 12 plays down to F3 points in single-digit territory, delivering the low-frequency response that makes SI's SQL Series unmatched at its price point.\u003c\/p\u003e\n    \u003ch3\u003eVolume Selection\u003c\/h3\u003e\n    \u003cp\u003e1.0 cubic foot net is the maximum of SI's recommended sealed volume range. Smaller volumes tighten Qtc and lose some low-end extension. Larger volumes fall outside SI's specification and compromise transient control. 1.0 cubic foot is where the SQL 12 delivers on its full low-end capability while staying inside the driver's engineered operating window.\u003c\/p\u003e\n    \u003ch3\u003eMounting Geometry\u003c\/h3\u003e\n    \u003cp\u003eThe baffle is cut to the SQL 12's exact 11.33\" cutout specification and doubled to 1.5\" total thickness at the mounting position. The SQL 12's 7\" mounting depth leaves comfortable internal clearance inside the 13.625\" deep cabinet. 8\/32 threaded inserts are pressed into the doubled baffle stock for full-depth thread engagement and secure retention at high excursion levels.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003ePerformance Series Construction, Sized for Real Power\u003c\/h2\u003e\n    \u003cdiv class=\"po-grid\"\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003eDouble Baffle Mounting Face\u003c\/h4\u003e\n        \u003cp\u003eThe mounting face uses a doubled 1.5\" total baffle thickness — two layers of 3\/4\" Langboard Elite MDF bonded together at the driver mounting position. Doubled baffle stock resists baffle flex and mounting screw pullout at the 1000-watt RMS power levels the SQL 12 delivers.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003e8\/32 Threaded Inserts Into Double Baffle\u003c\/h4\u003e\n        \u003cp\u003eThe baffle uses 8\/32 threaded inserts pressed into the doubled 1.5\" MDF backside, providing full-depth thread engagement for the supplied stainless steel mounting screws. No stripped pilot holes, no MDF damage from drywall screws, and secure retention at high excursion levels.\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 let the cabinet fold into shape with maximum glue surface. Dado joints lock the doubled baffle and rear panel into the side walls — no fasteners visible from outside, no exposed end grain at joints.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"po-card\"\u003e\n        \u003ch4\u003ePre-Wired Terminal Cup\u003c\/h4\u003e\n        \u003cp\u003eProline X ABS\/carbon fiber composite terminal cup, pre-wired with 12-gauge OFC inside the cabinet, with stainless steel hardware accepting both spade and banana terminations on the input side.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cp\u003eEvery panel is cut on ShopSabre CNC routers in our Tullahoma, TN facility. Tolerances that manual fabrication can't hold — joints close cleanly, baffle concentricity stays accurate, and internal volume is consistent unit to unit. The doubled baffle at the mounting position is bonded under clamping pressure for a monolithic 1.5\" stock at the point where structural integrity matters most.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eCustomize Your Build\u003c\/h2\u003e\n    \u003ch3\u003eCarpet Finish\u003c\/h3\u003e\n    \u003cp\u003e\u003cstrong\u003eDark Gray Trunkliner\u003c\/strong\u003e is the standard durable wrap, matched to most factory trunk and cargo-area carpet tones. \u003cstrong\u003ePlush Black\u003c\/strong\u003e (+$10) is a deeper, more luxurious nap that pairs well with blacked-out interiors and show builds.\u003c\/p\u003e\n    \u003ch3\u003eAcrylic Insert Color\u003c\/h3\u003e\n    \u003cp\u003eChoose \u003cstrong\u003eBlack, Blue, Red, or White\u003c\/strong\u003e for the front baffle insert to match your build. Or skip the insert entirely (-$40) for a clean, understated look. The insert is purely cosmetic — performance is identical across colors.\u003c\/p\u003e\n    \u003ch3\u003eBox-Only or Loaded\u003c\/h3\u003e\n    \u003cp\u003eAdd a Stereo Integrity SQL 12 Series 2 driver directly to your order in \u003cstrong\u003eDual 2-ohm or Dual 4-ohm\u003c\/strong\u003e impedance and \u003cstrong\u003ePaper or Carbon Fiber\u003c\/strong\u003e dust cap configurations. Already own your SQL 12? Order the enclosure box-only and drop in the driver you have.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eWiring the SQL 12 to Your Amplifier\u003c\/h2\u003e\n    \u003cp\u003eThe Stereo Integrity SQL 12 is a dual voice coil driver available in Dual 2-ohm (D2) or Dual 4-ohm (D4) configurations. The pre-wired terminal cup accepts either impedance version via 12-gauge OFC, with stainless steel input hardware.\u003c\/p\u003e\n    \u003cp\u003eA Dual 2-ohm SQL 12 wired in parallel presents a 1-ohm load. A Dual 2-ohm wired in series presents 4 ohms. A Dual 4-ohm SQL 12 wired in parallel presents 2 ohms, and wired in series presents 8 ohms. The SQL 12 is rated for 1000 watts RMS — aim for a clean, well-regulated amplifier delivering 750 to 1000 watts at your chosen impedance. At this power level, amplifier quality matters more than headline numbers — regulated power supply, low THD, and honest RMS ratings.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-section\"\u003e\n    \u003ch2\u003eBuilt in Tennessee, Backed by Audio Intensity\u003c\/h2\u003e\n    \u003cp\u003eEvery Performance Optimized enclosure is CNC-cut, assembled, and finished in our Tullahoma, TN facility. Components are pulled from inventory after your order is placed, then bonded and wrapped — a 2 to 5 business day assembly window before the box ships. No pre-built inventory sitting in warehouses, warping in storage. Each unit is built to order.\u003c\/p\u003e\n    \u003cp\u003eBacked by a 1-year limited warranty against structural failure and hardware defects. Questions on fitment, wiring, or amplifier pairing? \u003ca href=\"\/pages\/contact-us\"\u003eContact us\u003c\/a\u003e — we install this gear ourselves, in our own vehicles.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"po-cta\"\u003e\n    \u003ch2\u003eThe SQL 12, Engineered Correctly\u003c\/h2\u003e\n    \u003cp\u003eDriver-specific 1.0 cubic foot airspace, doubled baffle construction, V-groove and dado joinery, and Performance Series build quality sized for the SQL 12's 1000-watt RMS capability. The correct cabinet for a serious single 12 build.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Plush Black \/ Black","offer_id":43793847812185,"sku":"PO12-S SI BB","price":299.99,"currency_code":"USD","in_stock":true},{"title":"Plush Black \/ Blue","offer_id":43793847844953,"sku":"PO12-S SI BBL","price":299.99,"currency_code":"USD","in_stock":true},{"title":"Plush Black \/ Red","offer_id":43793847877721,"sku":"PO12-S SI BR","price":299.99,"currency_code":"USD","in_stock":true},{"title":"Plush Black \/ White","offer_id":43793847910489,"sku":"PO12-S SI BW","price":299.99,"currency_code":"USD","in_stock":true},{"title":"Plush Black \/ None","offer_id":43793847943257,"sku":"PO12-S SI B","price":279.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0689\/1389\/files\/performance-optimized-sealed-12-enclosure-stereo-integrity-12-sql-seriessubwoofer-enclosuresproline-x-6363168.png?v=1784976188"}],"url":"https:\/\/audiointensity.com\/collections\/stereo-integrity-subwoofer-box.oembed","provider":"Audio Intensity","version":"1.0","type":"link"}