Proline X
Proline X Jeep Wrangler Edition Dual 12" Down-Firing Sealed Subwoofer Enclosure | Stereo Integrity SQL-12
SKU: VS JW 12D-S DF-1
- Best For: Jeep Wrangler JL and JK Unlimited (4-door) | Down-Firing | Stereo Integrity SQL-12
- Net Volume: 2.05 cu ft (1.025 per chamber) | Sealed | Polyfill Pre-Installed
- Driver Match: Pair of Stereo Integrity SQL-12 (matched) | 11.375" Cutout | 8.06" Max Mounting Depth
- Construction: Dual Chamber | Double 1.5" Baffle, Flush Flange | Dado and V-Cut Joinery | Pre-Wired 12g OFC
Financing available. Choose Shop Pay Installments at checkout.
Build the Full System
Proline X Jeep Wrangler Edition Dual 12" Down-Firing Sealed Subwoofer Enclosure | Stereo Integrity SQL-12
Dual 12". Down-Firing.
Built for the 4-door Wrangler JL and JK.
The Proline X Jeep Wrangler Edition is a dual 12" sealed down-fire enclosure sized for the Stereo Integrity SQL-12. Two separate 1.025 cu ft chambers, a 1.5" double bottom baffle with the flange recessed flush, and a flat carpeted top that still carries cargo. CNC-cut in Tennessee from Langboard Elite MDF. Pre-wired 12g OFC. Feet included.
Designed for the Jeep Wrangler JL Unlimited 4-door (2018 to 2026) and Jeep Wrangler JK Unlimited 4-door (2007 to 2018). Not for 2-door Wranglers or the Jeep Gladiator. At 16" deep it needs the longer cargo floor of the 4-door; a 2-door has about 14" behind the upright rear seat. The enclosure is 38"W x 16"D x 10.31"H and sits in the cargo area without factory mounting point integration. Confirm your available cargo space before ordering.
Engineered for the Stereo Integrity SQL-12
Height was solved, not picked. The 38" x 16" footprint was fixed by the cargo area, and the height was set so the pair nets exactly 2.05 cu ft after the SQL-12's published 0.15 cu ft displacement is taken out of each chamber. Each driver gets 1.025 cu ft of sealed air.
At that volume the SQL-12 (Fs 34.1 Hz, Qts 0.57, Vas 22.5 L) lands at Qtc 0.759, Fc 45.4 Hz and F3 42.5 Hz anechoic. That is a slightly punchy sealed alignment with a mild lift at resonance, which suits a high-Qts driver in a cargo area. A textbook Qtc 0.707 would need a 13.4" tall box; this one gives up very little extension to stay low enough to load gear on top. Cabin gain and floor loading carry the response well below the anechoic F3.
Mounting geometry: 11.375" cutout (SI specifies 11.33"), 13.25" flange recess in the outer baffle layer, 8.06" maximum mounting depth against the SQL-12's 7.0". Other 12" drivers fit inside those limits, but the alignment above is computed for the SQL-12.
Down-Firing Is a Design Decision
Down-firing placement uses the cargo floor as an acoustic boundary. A driver firing into a hard surface at close range is loaded by it, reinforcing low-frequency output compared with the same driver firing into open air.
With both drivers facing down, the top surface is flat, unobstructed and load-bearing. The drivers are protected from cargo contact, and you keep the Wrangler's cargo utility.
Ground-Coupling Loads Both Drivers
Both SQL-12s fire into the Wrangler's cargo floor from a fixed standoff. The floor acts as an acoustic boundary that loads both cones at once, reinforcing output across the low-frequency range compared with a rear-firing box in the same space.
Two Fully Separate Chambers
A full-height divider splits the cabinet into two sealed chambers of 1.025 cu ft each. Each SQL-12 sees its own air spring, so one driver cannot load the other and both run the same alignment.
1.5" Double Bottom Baffle, Toe-Mounted
The bottom baffle is two laminated 0.75" layers. The outer layer is opened to 13.25" so the SQL-12's 12.91" flange drops in flush; the inner layer carries the 11.375" cutout and takes the mounting screws. The flange sits flush with the bottom face and the driver bolts into a full 0.75" of solid MDF.
Dado and V-Cut Joinery: No Butt Joints
Every panel joint is machined with interlocking dado and V-cut geometry. The panels register mechanically before adhesive is applied. Mechanical registration produces a tighter acoustic seal and a stiffer assembly than surface-bonded panels.
Pre-Wired 12g OFC to Both Chambers
Internal 12-gauge oxygen-free copper is pre-run to both cutouts and terminated at one side-mounted Proline X terminal cup. The lead to the far chamber passes the divider through a sealed port. Pull the leads, connect your drivers, done.
Langboard Elite MDF, Published Mill Data
Langboard Elite is a named, mill-documented panel with published density, internal bond and screw-holding figures. 200 psi internal bond. 325 lb face screw holding. The same panel stock used across the full Proline X lineup.
Four Jeep Front Graphic Versions
The front face carries a raised hex plate with a lasered acrylic insert set into a 0.25" pocket. Choose Version Jeep 1 (Rubicon), 2 (Sahara), 3 (Willys) or 4 (392) at checkout, white lettering on a black insert.
Feet Included: Correct Standoff Out of the Box
Feet are installed before shipment and set the standoff between the drivers and the cargo floor. No improvised spacers, no field modifications. The top stays flat and carpeted, so gear still loads on top.
Wiring Two SQL-12s
Plan on 700 to 1,000 W RMS per driver at the final wired impedance. For the dual 2 ohm SQL-12, wire each sub's coils in series (4 ohm per sub) and the two subs in parallel for a 2 ohm final load. For the dual 4 ohm SQL-12, coils in parallel and subs in parallel gives 1 ohm, which many amplifiers are not stable at; coils in series and subs in parallel gives 4 ohm. Match the final load to what your amplifier is rated for.
Built in Tennessee on ShopSabre CNC Routers
Every Proline X Vehicle Specific enclosure is CNC-cut and hand-assembled in Tullahoma, Tennessee. Dado depth, V-cut geometry, cutout and recess diameters, and external dimensions are held to spec on every unit. Internal volume is calculated, programmed and cut.
Finished in plush black automotive carpet with a lasered acrylic front insert. Every unit is inspected before shipment.
Vehicle Fitment
- Jeep Wrangler JL Unlimited 4-door (2018 to 2026)
- Jeep Wrangler JK Unlimited 4-door (2007 to 2018)
Not compatible with 2-door Wranglers or the Jeep Gladiator. Enclosure sits in the cargo area. No factory mounting point integration. Confirm available cargo dimensions (38"W x 16"D x 10.31"H) before ordering.
All Proline X Vehicle Specific Series enclosures are covered by a two-year manufacturer's warranty against defects in materials and workmanship. Built and inspected in our Tennessee facility. Contact Audio Intensity directly for warranty support.
| Internal Volume (Net) | 2.05 Cubic Feet total, 1.025 per chamber (after SQL-12 displacement) |
| Enclosure Type | Sealed, Dual Chamber |
| Woofer Orientation | Down-Firing |
| Optimized For | Stereo Integrity SQL-12 |
| Alignment (SQL-12) | Qtc 0.759, Fc 45.4 Hz, F3 42.5 Hz anechoic |
| Material | 3/4" Langboard Elite MDF |
| Bottom Baffle | 1.5" double layer, flange recessed flush (toe mount) |
| Construction | CNC-Cut / Dado and V-Cut Joinery / Full Divider |
| External Width | 38 Inches |
| External Depth | 16 Inches |
| External Height | 10.31 Inches |
| Woofer Cutout Diameter | 11.375 Inches |
| Flange Recess Diameter | 13.25 Inches |
| Max Mounting Depth | 8.06 Inches |
| Internal Wiring | 12-Gauge Oxygen-Free Copper (OFC) |
| Terminal Type | Proline X Terminal Cup, side mounted |
| Polyfill | Pre-Installed |
| Feet | Included |
| Finish | Plush Black Automotive Carpet with Lasered Acrylic Insert |
| Vehicle Fitment | Jeep Wrangler JL Unlimited 4-door (2018 to 2026); Jeep Wrangler JK Unlimited 4-door (2007 to 2018). Not 2-door, not Gladiator. |
01Is it a sealed driver?
Efficiency bandwidth product places the motor before anything else is decided.
02What the box does to it
1.025 cu ft against a 22.5 L Vas.
03The watts that reach Xmax (in this enclosure)
Travel scales with the square root of power, so there is one wattage that puts the cone exactly on 26.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 34.10 | Hz | free-air resonance |
| Qts | 0.570 | D2 | |
| Vas | 22.50 | L | equivalent compliance |
| Sd | 532.3 | cm² | effective piston area |
| Xmax | 26 | mm | 70% BL |
| Pe | 1000 | W | continuous RMS |
| SPL | 83.4 | dB | 1 W / 1 m, derived from T/S |
Driver parameters as published by Stereo Integrity published T/S. Curves computed against this enclosure’s actual net airspace.
Built From a Spec Sheet, Not a Sales Sheet
Every Proline X Vehicle Specific Series enclosure is CNC-cut from Langboard Elite MDF, 3/4" (18mm) panels produced to published mill specifications. Most enclosure manufacturers source generic MDF without published data. We can tell you the internal bond rating, the modulus of elasticity, the modulus of rupture, and the face and edge screw holding strength for every panel in this enclosure, because we chose the material based on those numbers, not on price or availability.
Langboard Elite is produced in the United States. The specifications below are pulled directly from Langboard's published mill data and are verifiable. This is the same panel stock used across the full Proline X lineup.
Langboard Elite MDF: Published Mill Data
| Property | Value | Why It Matters |
|---|---|---|
| Panel Stock | Langboard Elite MDF | Named, verifiable panel source, not generic "high-density MDF" |
| Thickness | 3/4" (18mm) | Industry standard for subwoofer enclosures; panels below this flex under pressure |
| Density | 48.5 lbs/ft³ | Higher density = less porosity, better screw retention, reduced resonance |
| Internal Bond | 200 psi | Measures resistance to delamination under sustained internal pressure. The most enclosure-relevant spec on this sheet |
| Modulus of Rupture (MOR) | 4,200 psi | Bending strength before the panel breaks, relevant for larger unsupported baffle spans |
| Modulus of Elasticity (MOE) | 410,000 psi | Stiffness under load; higher MOE means less panel flex under bass pressure, less resonance |
| Face Screw Holding | 325 lbs | How firmly the panel surface holds a screw; critical for baffle joint integrity over time |
| Edge Screw Holding | 250 lbs | Panel edge retention, relevant for every joint that isn't face-to-face |
200 psi: The Number That Actually Matters for Enclosures
The internal bond rating measures how well the MDF panel resists delamination under sustained pressure applied perpendicular to the face. In a subwoofer enclosure, every bass transient generates a pressure pulse that pushes outward on every panel simultaneously. A panel that begins to delaminate internally loses stiffness gradually. The symptoms are slow: a box that starts to sound softer, less defined, less punchy over months of use. 200 psi internal bond is the spec that determines how long this enclosure holds its acoustic integrity under daily use at real power levels.
410,000 psi MOE: Less Flex, Less Resonance
The modulus of elasticity measures panel stiffness, its resistance to bending under load. A stiffer panel flexes less under the pressure generated by a high-excursion driver at volume. Panel flex is a source of acoustic coloration: the panel itself begins to radiate sound at its own resonant frequency, adding distortion to the output. 410,000 psi stiffness is what keeps a Vehicle Specific Series wall from moving. Every wall is a stack of CNC-cut layers rather than a single unsupported panel, with dowel reinforcement running between the layers as tension hardware. There is no wide unsupported span left to flex and no butt joint to work loose, so resonance is controlled at the structure level, not the panel level. The bass you hear comes from the driver, not the box.
325 lb Face / 250 lb Edge: Joints That Stay Locked
Screw holding strength determines how firmly the panel grips a fastener at the face and at the edge. On a stack-fab enclosure there is no panel-to-panel butt joint being held together by fasteners. Screw holding matters where hardware threads into the shell, at the baffle and at the terminal cup. A panel with low screw holding strength lets those fasteners loosen under vibration, which opens an air gap and costs you the seal. 325 lb face screw holding strength means the hardware on a Proline X Vehicle Specific Series enclosure stays seated in the panel it was set into.
Named Panel Stock: Not "Premium MDF"
The phrase "premium MDF" or "high-density MDF" appears on marketing copy for enclosures across every price point, from $40 to $400. It is not a specification. It is a description with no defined standard. Langboard Elite is a named, sourced, mill-documented product with published data. We name it in our copy because naming it holds us accountable to the spec. You can look up Langboard Elite independently, verify the numbers on this page, and confirm you are getting what we say you are getting. That is the point.