Proline X
Performance Optimized Down Fire Wide Sealed Dual 10" Enclosure | Skar Audio EVL-10
SKU: PO 10D-S DFW EVL10
- Alignment: 0.653 cu ft net per chamber. D2: Qtc 0.690, Fc 51.5 Hz, F3 52.8 Hz. D4: Qtc 0.721, Fc 52.3 Hz, F3 51.3 Hz
- Down Fire Wide: 41"W x 12"D x 8.75"H in down fire position, excludes standoffs, sized for under the rear seat of a truck or SUV
- Drivers: Pair of Skar Audio EVL-10 (D2 or D4), 1000 W RMS each, 23.5 mm Xmax, 7.16 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 10.5 in
Financing available. Choose Shop Pay Installments at checkout.
Performance Optimized Down Fire Wide Sealed Dual 10" Enclosure | Skar Audio EVL-10
More enclosures cut for Skar Audio subwoofers: Skar Audio Subwoofer Boxes
Proline X Performance Optimized Down Fire Wide Dual 10" Sealed
Under rear seat fitment for trucks and SUVs. Cut and tuned for a pair of Skar Audio EVL-10
The Down Fire Wide Format
Down Fire Wide is the Performance Optimized answer to a specific problem: the space under the rear seat of a truck or SUV, or a narrow cargo floor, is long and shallow, and the standard 30 by 15 inch Down Fire cabinet will not go in it.
So the cabinet is turned sideways. This one runs 41 inches wide by 12 inches deep by 8.75 inches tall, measured in the down fire position. It is cut for the same Skar Audio EVL-10 pair as our standard box, 3 inches shallower front to back and 11 inches longer. The airspace lost from the depth is recovered along the length, and the height is solved to the driver.
Measure the depth before anything else. Under seat spaces vary widely between cab configurations, and depth is almost always the limiting dimension. If you have 15 inches of depth, the standard 30 by 15 inch cabinet at 9.35 inches tall is the pick. If your space stops at 12 inches deep and you have 41 inches of run, this cabinet fits. The standoffs add 1.75 inches, so the installed height is 10.5 inches.
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. 24.5 by 13.5 inches on the 10 inch. | Shared 30 by 15 inch platform on most builds. Down Fire Wide variants like this one run long and shallow for under seat fitment. | Compact per driver footprint. 21.5 by 14.5 inches on the 10 inch. |
| Front baffle | Single, 3/4 inch. | Double layer, outer layer machined as a flush recess. 1.5 inch. | Double, 1.5 inch. |
| Driver mounting | Solid flange. You drill your own mounting holes. | 8/32 threaded inserts, stainless machine screws included. | 8/32 threaded inserts, stainless machine screws included. |
| Joinery | V-groove and dado, CNC cut. | V-groove and dado, CNC cut, 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 Skar EVL-10
Nothing about this cabinet is generic. The baffles are cut to 9.39 in, Skar's published cutout, and the round 10.89 in frame sits on the 12 inch deep baffle with material fore and aft.
The EVL-10 is Skar Audio's 10 inch, rated 1000 watts RMS, with 23.5 mm of one-way excursion. It is 7.16 inches deep, which matters on a down fire, where the motor rises into the cabinet: here it clears the top panel by 0.84 inches against a 0.75 inch minimum. Every figure comes from the Thiele-Small table Skar prints on its EVL-10 product page.
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 0.653 cubic feet net 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, and on a 41 inch cabinet it ties the front and rear walls together mid span. One shared side mounted terminal cup feeds both driver positions.
Net Volume, Not Gross
Total gross volume is 1.521 cubic feet. After the divider and an estimated 0.092 cubic feet of displacement per driver, each chamber nets 0.653 cubic feet, 1.307 net total, matching the 0.65 per chamber our standard 30 by 15 dual EVL-10 was built to. Skar publishes no displacement, so that figure is our estimate.
The chamber is sized between the two coils' flat-alignment volumes, so the D2 lands just under the 0.707 reference and the D4 just over it. Skar's own recommended sealed range is larger, from 1.25 to 1.5 in cubic feet net per driver, which is not a practical down fire dual.
Per chamber the EVL-10 D2 reads Qtc 0.690, Fc 51.5 Hz, F3 52.8 Hz and the D4 reads Qtc 0.721, Fc 52.3 Hz, F3 51.3 Hz.
| Driver | System Qtc | Fc | F3 |
|---|---|---|---|
| EVL-10 dual 2 ohm | 0.690 | 51.5 Hz | 52.8 Hz |
| EVL-10 dual 4 ohm | 0.721 | 52.3 Hz | 51.3 Hz |
True net, not marketing net. Internal volume is calculated from the machined cavity dimensions and the driver's displacement, estimated here because Skar publishes none, not guessed from external dimensions minus wall thickness.
Down Fire Wide Construction
Cut with V-groove and dado joinery on our ShopSabre routers from Langboard Elite 3/4 inch MDF, a dense 48.5 lb/ft³ board with a 200 psi internal bond and 410,000 psi MOE. Every panel joint is a machined interlocking groove that mechanically locks before adhesive is applied, which keeps the cabinet airtight under sustained pressure cycling. Corners are square on Down Fire cabinets.
The cabinet measures 41 inches wide by 12 inches deep by 8.75 inches tall, measured in the down fire position. Standoffs ship with the enclosure but are not installed; they add 1.75 inches, for an installed height of 10.5 inches.
1.5 Inch Double Baffle
Two 3/4 inch layers laminated to 1.5 inches, the outer layer machined as a flush recess so the driver bolts to the inner layer, with a threaded insert kit and stainless machine screws included. Skar prints no bolt circle, so the inserts ship loose.
Separate Chambers
A bonded full-height 3/4 inch divider gives each driver its own 0.653 cubic feet net and its own polyfill, and ties the walls together mid span.
One Shared Terminal Cup
Proline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, side mounted and pre-wired in 12 gauge OFC to both driver positions in parallel.
Polyfill Installed
Polyfill is installed as a light wall lining in each chamber. It controls internal reflections and is not packed to change the acoustic volume.
Motor Clearance
The 7.16 inch motor rises into the cavity and clears the top panel by 0.84 inches, against a 0.75 inch minimum. Airspace set the height, not clearance.
Power, Mounting and Warranty
Skar rates the EVL-10 at 1000 watts RMS, 2000 watts RMS combined. A pair of EVL-10 D2 drivers can land on 0.5 ohm with all four coils in parallel, 2 ohms as series pairs in parallel, or 8 ohms all in series. A pair of EVL-10 D4 drivers can land on 1 ohm with all four coils in parallel, 4 ohms as series pairs in parallel, or 16 ohms all in series. 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 load against your amplifier's minimum stable impedance before powering the system.
Skar prints no bolt circle for the EVL-10, 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. Skar does not publish a position on down firing this driver, and this cabinet makes no claim on their behalf; the standoffs ship uninstalled, so front or up firing is your call at install time.
Bring your own pair of EVL-10; the drivers are purchased separately. The enclosure carries a 1 year limited warranty.
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 Wide |
| Compatible Driver | Skar Audio EVL-10 D2 or D4, quantity 2. Direct fit |
| Configuration | Dual 10 inch, two separate chambers, sealed down fire |
| Mounting Position | Under the rear seat of trucks and SUVs, or a narrow cargo floor, baffle facing down on standoffs |
| Firing Direction | Downward. Standoffs ship uninstalled, so front or up firing is also possible |
| External Width | 41 in |
| External Depth | 12 in |
| External Height | 8.75 in in the down fire position, excludes standoffs |
| Installed Height | 10.5 in including the 1.75 in standoff |
| Internal Volume, Gross | 1.521 cu ft total |
| Internal Volume, Net Acoustic | 0.653 cu ft per chamber, 1.307 cu ft total, after the divider and an estimated 0.092 cu ft displacement per driver |
| Height Set By | Airspace; clearance alone would allow a lower cabinet |
| Driver Mounting Depth | 7.16 in required, 0.84 in clearance above the motor |
| Alignment per chamber, D2 | Qtc 0.690, Fc 51.5 Hz, F3 52.8 Hz anechoic |
| Alignment per chamber, D4 | Qtc 0.721, Fc 52.3 Hz, F3 51.3 Hz anechoic |
| Comparison, Standard 30x15 | 30.00 x 15.00 x 9.35 in, built to 0.65 cu ft net per chamber |
| Skar Recommended Sealed | 1.25 to 1.5, cubic feet net of driver, bracing and port |
| Woofer Opening | 9.39 in, Skar's published cutout |
| Frame Outer Diameter | 10.89 in |
| Bolt Circle | Not printed by Skar; threaded insert kit included |
| Driver Displacement | 0.092 cu ft, estimated; Skar publishes none |
| D2 Fs / Qts / Qes / Qms / Vas | 44.0 Hz / 0.59 / 0.66 / 5.44 / 6.8 L |
| D4 Fs / Qts / Qes / Qms / Vas | 45.0 Hz / 0.62 / 0.69 / 5.21 / 6.5 L |
| Driver Sd | 314 cm2, published by Skar |
| Xmax | 23.5 mm one way, Skar spec |
| Driver Power Handling | 1000 W RMS each, Skar spec |
| Wiring Options | Pair of D2: 0.5, 2 or 8 ohm. Pair of D4: 1, 4 or 16 ohm. Series wiring is the safe default |
| Parameter Source | skaraudio.com EVL-10 product page, T/S Parameters and Subwoofer Measurements |
| 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 insert kit included, NOT pre-installed: Skar prints no bolt circle |
| 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 |
| 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
0.653 cu ft against a 6.8 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 23.5 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 44.00 / 45.00 | Hz | free-air resonance |
| Qts | 0.590 / 0.620 | dual 2 ohm / dual 4 ohm | |
| Vas | 6.80 / 6.50 | L | equivalent compliance |
| Sd | 314.1 | cm² | effective piston area |
| Xmax | 23.5 | mm | one-way linear travel |
| Pe | 1000 | W | continuous RMS |
| SPL | 81.3 | dB | 1 W / 1 m, derived from T/S |
Driver parameters as published by Skar Audio EVL-10 product page. 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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