Proline X
Arc Audio ARC 10 Box: Sealed 10" Down Fire Wide Enclosure
SKU: PO 10-S DFW Arc
- Alignment: 1.053 cu ft net, Qtc 0.621, Fc 37.9 Hz, F3 43.9 Hz (D2); D4: Qtc 0.659, Fc 38.0 Hz, F3 41.0 Hz
- Down Fire Wide: 41"W x 12"D x 7"H in down fire position, sized for under the rear seat of a truck or SUV
- Driver: ARC Audio ARC 10, 250W RMS / 500W musical, 16mm Xmax, 23.8 Hz Fs, 5.5" mounting depth
- Height note: Set by the 5.5" motor with 0.75" clearance above it, so the box holds more air than Arc's gross optimum; lower Qtc, the safe direction
- Build: Square corners, 1.5" double baffle, windowed U-brace, side mounted terminal cup, feet ship uninstalled (+1.75")
Financing available. Choose Shop Pay Installments at checkout.
Arc Audio ARC 10 Box: Sealed 10" Down Fire Wide Enclosure
More enclosures cut for Arc Audio subwoofers: Arc Audio Subwoofer Boxes
Proline X Performance Optimized Down Fire Wide 10" Sealed
Under rear seat fitment for trucks and SUVs. Cut and tuned for the ARC Audio ARC 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 7 inches tall, measured in the down fire position. It is cut for the same ARC 10 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 7.125 inches tall is the pick. If your space stops at 12 inches deep and you have 41 inches of run, this cabinet fits. The feet add 1.75 inches, so the installed height is 8.75 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 ARC Audio ARC 10's own published numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.
Built Around the ARC 10
The baffle is bored to the ARC 10's 9 1/4 inch cutout, and the 10 1/4 inch frame sits on the 12 inch deep baffle. The cabinet height is set by its 5 1/2 inch mounting depth.
The ARC Series was designed by one of the leading car audio subwoofer acoustical engineers in the United States, and the design brief was small to moderate enclosures with dynamic power handling. That intent shows in the numbers: a free-air resonance of 23.8 Hz with a Qts of 0.390 and 45.75 litres of Vas on the Dual 2-Ohm.
Construction is a high-temperature black anodized voice coil, a one-piece molded rubber surround, a stamped steel basket, and a progressive flat layered spider with integrated tinsel leads. 16mm of one-way linear excursion across 49.60 square inches of cone. 250 watts RMS, 500 watts musical.
Why This Runs Larger Than Arc's Recommendation
ARC Audio publishes a sealed range for the ARC 10 of 0.65 minimum, 0.75 optimum and 0.90 maximum, all gross, which is the convention Arc uses throughout their manual. Their optimum is well chosen for the driver. It is also out of reach in a down fire cabinet, because the ARC 10 is physically taller than the box that volume produces.
Height on this cabinet is set by the driver's mounting depth, not by a volume target. The motor needs 0.75 inch of clearance above it inside the cabinet, and at that height the 41 by 12 footprint holds 1.053 cubic feet net, more than the 1.00 the standard box was built to. More air behind the same driver lowers Qtc, which is the safe direction.
The cabinet stands 7 inches tall and holds 1.111 cubic feet gross. After the driver's 0.05 cubic feet of published displacement that is 1.053 net, and the ARC 10 Dual 2-Ohm lands at Qtc 0.621, Fc 37.9 Hz, F3 43.9 Hz.
Not a compromise so much as a different point on the same curve. Qtc 0.621 is more damped than the textbook 0.707 reference: a gentler corner, lower group delay and tighter transient control, which suits a down fire cabinet firing into cabin gain.
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 7 inches tall, measured in the down fire position. Feet ship with the enclosure but are not installed; they add 1.75 inches, for an installed height of 8.75 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 8/32 threaded inserts at the driver position.
Windowed U-Brace
A windowed U-brace dadoed to the shell ties the front and rear walls together across the 41 inch span without walling off the airspace.
Side-Mounted 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.
Polyfill Installed
Polyfill is installed as a light wall lining. It controls internal reflections and is not packed to change the acoustic volume.
Power and Wiring
ARC Audio rates the ARC 10 at 250 watts RMS continuous with 500 watts musical, and an amplifier power range of 5 to 500 watts. Their manual is direct about the distinction: the RMS figure is the recommended continuous power for long term use, the driver will take roughly twice that in short bursts, and sustained operation above the RMS rating will burn the voice coil and is not covered under warranty.
Available in Dual 2-Ohm and Dual 4-Ohm. Both are dual voice coil, so final impedance is set at the driver. Headline figures are the Dual 2-Ohm. The Dual 4-Ohm (Fs 23.5 Hz, Qts 0.407, Vas 48.37 L) lands at Qtc 0.659, Fc 38.0 Hz, F3 41.0 Hz in this box.
Bring your own ARC 10. The enclosure carries a 1 year limited warranty.
Cut for the Driver, Not the Catalog
Built one at a time in Tullahoma, Tennessee, around the smallest height this driver physically allows in a 41 by 12 footprint.
| Series | Proline X Performance Optimized Down Fire Wide |
| Compatible Driver | ARC Audio ARC 10, Dual 2-Ohm or Dual 4-Ohm. Direct fit, no other driver |
| Enclosure Type | Sealed, down fire, floor coupled |
| Intended Fitment | Under the rear seat of trucks and SUVs, or narrow cargo floors, where depth is the limiting dimension |
| Firing Direction | Down firing, driver fires toward the floor |
| External Width | 41 in |
| External Depth | 12 in |
| External Height | 7 in |
| Installed Height | 8.75 in with the 1.75 in feet |
| Dimension Reference | All external dimensions measured in down fire position, excluding feet |
| Internal Volume, Gross | 1.111 cu ft |
| Internal Volume, Net Acoustic | 1.053 cu ft after displacement |
| Height Set By | Driver clearance: 5.5 in mounting depth, 0.75 in above the motor |
| Arc Suggested Sealed, Gross | 0.65 minimum, 0.75 optimum, 0.90 maximum. Not reachable at this mounting depth, see description |
| System Qtc | 0.621 (Dual 2-Ohm), 0.659 (Dual 4-Ohm) |
| Predicted Fc | 37.9 Hz (Dual 2-Ohm), 38.0 Hz (Dual 4-Ohm) |
| Predicted F3 | 43.9 Hz (Dual 2-Ohm), 41.0 Hz (Dual 4-Ohm) |
| Comparison, Standard 30x15 ARC 10 | 30 x 15 x 7.125 in, built to 1.00 cu ft net. This box holds a little more air |
| Driver Fs | 23.8 Hz (Dual 2-Ohm), 23.5 Hz (Dual 4-Ohm) |
| Driver Qts | 0.390 (Dual 2-Ohm), 0.407 (Dual 4-Ohm) |
| Driver Qes / Qms | 0.431 / 4.094 (Dual 2-Ohm) |
| Driver Vas | 45.75 L (Dual 2-Ohm), 48.37 L (Dual 4-Ohm) |
| Driver Re | 1.00 ohm parallel / 4.03 ohm series (Dual 2-Ohm) |
| Driver Sd | 49.60 sq in |
| Driver Xmax | 16mm one way linear |
| Driver Displacement | 0.05 cu ft, published by Arc Audio |
| Driver Sensitivity | 87 dB, 1 W at 1 m |
| Driver Power Handling | 250 W RMS continuous, 500 W musical |
| Amplifier Power Range | 5 to 500 W, Arc Audio spec |
| Voice Coil Configuration | Dual voice coil, impedance set at the driver |
| Driver Voice Coil | High temperature black anodized |
| Driver Surround | One piece molded rubber |
| Driver Spider | Progressive flat layered with integrated tinsel leads |
| Driver Basket | Stamped steel |
| Mounting Depth | 5 1/2 in, Arc Audio spec |
| Woofer Opening | 9 1/4 in direct fit |
| Driver Outside Diameter | 10 1/4 in |
| Feet | 1.75 in, included, shipped uninstalled |
| Material | Langboard Elite MDF |
| Construction | CNC cut, dado and V groove joinery, windowed U-brace |
| Panel Thickness | 0.75 in |
| Front Baffle | 1.5 in double baffle, outer layer flush recess |
| Corner Profile | Square, Down Fire series standard |
| Driver Mounting | 8/32 threaded inserts, stainless machine screws included |
| Terminal Cup | Proline X ABS and carbon fiber composite, side mounted |
| Internal Wiring | 12 gauge OFC |
| Damping | Polyfill installed, light wall lining |
| Carpet | Plush Black |
| Bundle Options | Enclosure only, bring your own ARC Audio ARC 10 |
| Warranty | 1 Year Limited |
| Built In | Tullahoma, Tennessee |
What this cabinet is built from
The cabinet is designed from Arc Audio’s figures taken as printed. This enclosure gives the ARC 10 1.053 cubic feet net; its system Q and half-power frequency are on the Specifications tab. If Arc Audio publishes a corrected parameter set, or the driver is measured, the graphs will be modeled and added here.
Driver parameters as published by Arc Audio.
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.
Shop By Series
