Proline X
JL Audio 10W1v3 Dual Box: Sealed 10" Down Fire Enclosure
SKU: PO 10D-S DF W1V3
- Alignment: 0.55 cu ft net per chamber, Qtc 0.85 to 0.87, F3 42.3 Hz on the 2 ohm version and 43.1 Hz on the 4 ohm version
- Drivers: Pair of JL Audio 10W1v3 (2 ohm version and 4 ohm version), 300 W RMS each, 11.4 mm Xmax, 4.60 in mounting depth
- Chambers: Two fully separate sealed chambers, 3/4" MDF full divider, one shared side-mounted terminal cup
- Standoffs: Included, 1.75 in, shipped uninstalled. Installed height near 9.62 in
- Cabinet: 30.00"W x 15.00"D x 7.87"H in down fire position, excludes standoffs, square corners
Financing available. Choose Shop Pay Installments at checkout.
JL Audio 10W1v3 Dual Box: Sealed 10" Down Fire Enclosure
More enclosures cut for JL Audio subwoofers: JL Audio Subwoofer Boxes
Proline X Performance Optimized Down Fire Dual 10" Sealed
Cut and tuned for a pair of JL Audio 10W1v3
Performance, Performance Optimized, and Micro
Proline X builds three tiers of Down Fire enclosure. The difference is not finish or materials, it is whether the cabinet was designed for a category or for a driver, and how much of the fitting work is already done for you.
| Performance | Performance Optimized | Micro Series | |
|---|---|---|---|
| Fitment | Universal. Accepts any subwoofer that clears the published cutout and mounting depth. | Woofer specific. Cut for one named subwoofer, with cutout, mounting depth, magnet clearance and displacement drawn in CAD from that driver. | Woofer specific. Cut for one named subwoofer. |
| Footprint | Sized to the driver diameter. | A shared 30 by 15 inch platform, with cabinet height as the variable. This build sits on that platform at 7.87 inches tall, the height that gives each driver its own 0.55 cubic feet. | Compact per driver footprint. |
| Front baffle | Single, 3/4 inch. | Double, 1.5 inch, outer layer machined as a flush recess. | Double, 1.5 inch. |
| Driver mounting | Solid flange. You drill your own mounting holes. | Threaded inserts pre-installed on JL's 9.7 inch bolt circle, stainless machine screws included. | Threaded inserts, stainless machine screws included. |
| Joinery | V-groove and dado, CNC cut. | V-groove and dado, CNC cut, full-height divider and perimeter cross brace. | Stack fab, dowel reinforced. |
| Published alignment | Modeled Qtc profiles across a range of drivers. No single response curve. | A real predicted Qtc and F3 for that exact driver, calculated from its own Thiele-Small parameters. | Target alignment described in the listing. |
| Carpet | Gray standard, black optional. | Plush black. | Plush black. |
| Warranty | 1 year limited. | 1 year limited. | 2 years. |
Feet ship with every tier, uninstalled on purpose. Mount them where your floor wants them for a down fire install, or leave them off and run the cabinet front firing or up firing. The orientation is yours to choose.
This page is a Performance Optimized enclosure. The airspace, the cutout and the cabinet height all come from the driver's own numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.
Built Around a Pair of JL Audio 10W1v3
Nothing about this cabinet is generic. The baffle is cut to 9.0625 in, JL's published mounting hole, under the 10.5 in frame. The airspace lands on 0.55 cubic feet net per chamber, JL's own recommended sealed airspace for the 10W1v3.
The 10W1v3 is JL's 10 inch W1v3, a single voice coil driver sold as a 2 ohm and a 4 ohm version, rated 300 watts RMS with 11.4 mm of one-way excursion, 4.60 inches of mounting depth on a 10.5 inch frame. It sits 4.60 inches deep, which matters on a down fire, where the motor rises into the cabinet. Every Thiele-Small figure comes from JL's own owner's manual for the 10W1v3, both columns, and the table holds together: each column reproduces its own printed Qts, the two versions agree on Vas and resonance, and JL's own 0.55 cubic foot sealed box reproduces JL's printed Qtc of 0.853 and 0.868.
Two Chambers, Not One Volume
This enclosure follows the Proline X standing rule for dual sealed builds: two fully separate chambers split by a bonded full height 3/4 inch MDF divider, each driver in its own 0.55 cubic feet with its own polyfill.
Two drivers sharing one sealed volume interact acoustically. Each driver's compression phase becomes the pressure environment the other is working against, which smears transient response and blurs the alignment either would have on its own. A full divider removes that entirely. One shared side mounted terminal cup feeds both driver positions, so the cabinet stays a single connection point.
Net Volume, Not Gross
Each chamber is built at 0.55 cubic feet net per driver, out of 1.21 gross after the divider and the drivers. JL publishes the driver displacement, 0.037 cubic feet, and it is taken out of the net figure for each driver.
True net, not marketing net. Internal volume is calculated from the machined cavity dimensions and the driver's displacement, not guessed from external dimensions minus wall thickness.
0.55 cubic feet net per chamber on JL's published figures: the 2 ohm version reads Qtc 0.854 with resonance at 49.4 Hz and half power at 42.3 Hz, and the 4 ohm version reads Qtc 0.868 with resonance at 50.9 Hz and half power at 43.1 Hz. One cabinet serves both versions. The volume is JL's own recommended sealed airspace for the 10W1v3, 0.55 cubic feet per driver, and on JL's published parameters this chamber reproduces JL's printed Qtc, fc and F3 for both versions. That is above maximally flat: punchy, with a clear lift near resonance and extra midbass, the alignment JL itself recommends.
| Driver (per chamber) | System Qtc | fc | F3 |
|---|---|---|---|
| 10W1v3 2 ohm version | Qtc 0.854 | 49.4 Hz | 42.3 Hz |
| 10W1v3 4 ohm version | Qtc 0.868 | 50.9 Hz | 43.1 Hz |
Down Fire Construction
Cut with V-groove and dado joinery on our ShopSabre routers from Langboard Elite 3/4 inch MDF. Every panel joint is a machined interlocking groove that mechanically locks before adhesive is applied, which keeps the cabinet airtight under sustained pressure cycling. Corners are square on Down Fire cabinets.
The cabinet measures 30.00 inches wide by 15.00 inches deep by 7.87 inches tall, measured in the down fire position and excluding standoffs. Plan the space around the installed height rather than the cabinet height: the standoffs hold 1.75 inches under the baffle, so the finished stack sits near 9.62 inches.
Double Baffle, Flush Recess
The front baffle is 1.5 inches, two bonded 3/4 inch sheets, with the outer layer machined as a flush recess so the driver bolts to the inner layer. That recovers 3/4 inch of internal clearance.
Side-Mounted Terminal Cup
Proline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, pre-wired in 12 gauge OFC to both driver positions. Side mounted so it stays accessible with the baffle facing the floor.
Standoffs Included
JL publishes no front clearance figure for the 10W1v3, so this cabinet uses the Proline X standard 1.75 inch standoff, shipped with every enclosure and left uninstalled so you can place them to suit your floor. At that height the floor slot is 0.93 times the cone area, under the 1.0 we aim for. With 11.4 mm of excursion this cone moves a lot of air at its limit, so for hard use mount taller feet or run the cabinet front firing; at daily levels the slot is not the limit.
Motor Clearance and Orientation
The motors rise off the baffle into the cavity, so on a down fire cabinet the clearance that matters runs to the top panel. The 4.60 inch mounting depth puts the motor 3.10 inches into a 5.62 inch cavity, leaving 2.52 inches above the motor against a 0.75 inch minimum. Height was set by the airspace, above the minimum the clearance alone would have required.
JL does not publish a position on down firing this driver, and this cabinet makes no claim on their behalf. The feet ship uninstalled, so if you would rather run it front firing or up firing, that is a decision you can make at install time without changing anything about the enclosure.
Power, Mounting and Warranty
JL rates the 10W1v3 at 300 watts RMS, 600 watts RMS combined. JL sells the 10W1v3 as a single voice coil driver in a 2 ohm and a 4 ohm version; a matched pair should share an impedance. A pair of 2 ohm versions lands on 4 ohms in series or 1 ohm in parallel. A pair of 4 ohm versions lands on 2 ohms in parallel or 8 ohms in series. Many amplifiers are not stable at 1 ohm, so on the 2 ohm version series wiring to 4 ohms is the safe default. Confirm the load against your amplifier's minimum stable impedance before powering the system.
Threaded inserts are pre-installed on JL's 9.7 inch bolt circle, with stainless machine screws, so the 10W1v3 bolts straight in. The enclosure carries a 1 year limited warranty. Bring your own pair of 10W1v3; the drivers are purchased separately.
Cut for the Driver, Not the Catalog
Built one at a time in Tullahoma, Tennessee, with standoffs and a 1 year limited warranty. Questions on fitment or amplifier matching, call 931-563-5151.
| Specification | Value |
|---|---|
| Series | Proline X Performance Optimized Down Fire |
| Compatible Driver | JL Audio 10W1v3 (2 ohm version and 4 ohm version), quantity 2. Direct fit |
| Configuration | Dual 10 inch, two separate chambers, sealed down fire |
| Mounting Position | Trunk or cargo floor, baffle facing down on standoffs |
| Firing Direction | Downward. Feet ship uninstalled, so front or up firing is also possible |
| External Width | 30.00 in |
| External Depth | 15.00 in |
| External Height | 7.87 in in the down fire position, excludes standoffs |
| Installed Height | 9.62 in including the 1.75 in standoff |
| Internal Volume, Gross | 1.21 cu ft total |
| Internal Volume, Net Acoustic | 0.55 cu ft per chamber after the divider and the driver displacement |
| Height Set By | Airspace; clearance alone would allow a lower cabinet |
| Driver Mounting Depth | 4.60 in required, 2.52 in clearance above the motor |
| Floor Slot | 0.93 times the cone area at the 1.75 in standoff |
| Alignment, 2 ohm version per chamber | Qtc 0.854, fc 49.4 Hz, F3 42.3 Hz anechoic |
| Alignment, 4 ohm version per chamber | Qtc 0.868, fc 50.9 Hz, F3 43.1 Hz anechoic |
| Woofer Opening | 9.0625 in, two, JL's published mounting hole |
| Frame Outer Diameter | 10.5 in, JL spec |
| Bolt Circle | 9.7 in, JL spec; threaded inserts pre-installed |
| Driver Displacement | 0.037 cu ft per driver, JL spec |
| 2 ohm version Fs / Qts / Qes / Qms / Vas | 25.23 Hz / 0.436 / 0.463 / 7.246 / 44.15 L |
| 4 ohm version Fs / Qts / Qes / Qms / Vas | 26.15 Hz / 0.446 / 0.475 / 7.243 / 43.41 L |
| Driver Sd | 346 cm2, JL spec |
| Xmax | 11.4 mm one way, JL spec |
| Driver Power Handling | 300 W RMS per driver |
| Wiring Options | JL sells the 10W1v3 as a single voice coil driver in a 2 ohm and a 4 ohm version; a matched pair should share an impedance. A pair of 2 ohm versions lands on 4 ohms in series or 1 ohm in parallel. A pair of 4 ohm versions lands on 2 ohms in parallel or 8 ohms in series. Many amplifiers are not stable at 1 ohm, so on the 2 ohm version series wiring to 4 ohms is the safe default. |
| Parameter Source | JL Audio 10W1v3-2 / 10W1v3-4 owner's manual, both columns |
| Material | Langboard Elite MDF |
| Construction | CNC cut, V-groove and dado joinery, square corners |
| Panel Thickness | 0.75 in |
| Front Baffle | 1.5 in double baffle, outer layer machined as a flush recess |
| Internal Bracing | Full-height 3/4 in divider |
| Driver Mounting | Threaded inserts pre-installed on the 9.7 in bolt circle, stainless machine screws included |
| Terminal Cups | One Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC to both driver positions |
| Standoffs | Included, 1.75 in, shipped uninstalled |
| Damping | Light polyfill wall lining in both chambers, does not alter acoustic volume |
| Carpet | Plush black |
| Shipping Weight | 39 lb |
| Warranty | 1 Year Limited |
| Built In | Tullahoma, Tennessee |
01Is it a sealed driver?
Efficiency bandwidth product places the motor before anything else is decided.
02What the box does to it
0.55 cu ft against a 44.1 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 11.4 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 25.23 / 26.15 | Hz | free-air resonance |
| Qts | 0.436 / 0.446 | 10W1v3-2 / 10W1v3-4 | |
| Vas | 44.15 / 43.41 | L | equivalent compliance |
| Sd | 346.0 | cm² | effective piston area |
| Xmax | 11.4 | mm | one-way, voice coil overhang method, as JL publish it |
| Pe | 300 | W | continuous RMS |
| SPL | 83.7 | dB | 1 W / 1 m, derived from T/S |
Driver parameters as published by JL Audio owner's manual. Curves computed against this enclosure’s actual net airspace.
Built From a Spec Sheet, Not a Sales Sheet
Every Proline X Performance 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 in our 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 combined with V-groove and dado joinery means the panels stay rigid and the bracing controls resonance 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. This matters most at the baffle joint, where the front panel meets the side panels and where the driver is mounted. A panel with low screw holding strength allows fasteners to loosen over time under vibration, leading to air gaps at the joint and loss of acoustic seal. 325 lb face screw holding strength means the baffle hardware stays put. Combined with dado joinery and adhesive, the front panel on a Proline X Performance Series enclosure is not going anywhere.
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.
Why Proline X?
Most enclosures are built to a price point. Proline X is built to a spec. Every box starts with published-data MDF, gets CNC-cut to exact internal volume, and is assembled by hand in our Tennessee facility. The difference shows up in the measurements, and in how the box holds up two years into daily use.
CNC-Cut to Spec
Panels are machine-cut on ShopSabre CNC routers and joined with V-groove and dado joinery. Consistent geometry, no hand-cut variance, no gaps at the joints.
Handcrafted in USA
Hand-assembled at our facility in Tullahoma, TN. Every enclosure is inspected before it ships.
Tuned to the Build
Internal volume and port geometry are calculated to spec and CNC-cut to exact dimensions. The box performs the same way every time.
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