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Read Article →Proline X
The Proline X Single 10" Sealed Down-Fire System pairs the Arc Audio A10 10" shallow-mount subwoofer with a Proline X sealed down-fire enclosure built at our Tennessee facility. Net internal volume is 0.60 ft³ — centered within Arc Audio's published optimum range of 0.40–0.90 ft³ for the A10 in a sealed alignment. The down-fire orientation mounts the driver facing the floor, which keeps the cone protected from physical contact and allows the enclosure to sit flat in under-seat and trunk applications without the driver exposed. The A10 ships pre-wired to your selected impedance — Dual 2-ohm (wired parallel to 1 ohm) or Dual 4-ohm (wired parallel to 2 ohms). Select your amplifier's target impedance at checkout.
Every panel is CNC-cut from 3/4" Langboard Elite MDF at our Tennessee facility — a mill-certified panel stock with a 200 psi internal bond rating, 410,000 psi modulus of elasticity, and 325 lb face screw holding strength. In a sealed enclosure, panel integrity is the entire acoustic story. The sealed air volume behind the driver is what controls cone motion — any flex or air leak at a joint directly corrupts that suspension. This box does not flex and does not leak.
Version III construction uses V-groove combined with dado joinery throughout, and the front baffle is 1.5" thick — two layers of 3/4" MDF laminated together. The A10's 3.77" mounting depth is a shallow-mount driver; the double baffle eliminates the flex point directly behind the driver where internal pressure concentrates during high-excursion playback. The terminal cup is built in-house at our Tennessee facility — ABS/Carbon Fiber Composite body, recessed mount, stainless steel hardware, aluminum landing plates, copper ring terminals, and 12g OFC speaker wire pre-installed. Nothing to source. Nothing to upgrade. It ships ready to wire.
Shipping is included in the price. At 24.5" wide and 5.25" tall, this is a compact freight shipment — but a loaded enclosure ships as a packaged unit. That cost is built into what you see. No freight line item on your order confirmation. What you see is what you pay.
| Enclosure Type | Sealed — Down-Fire |
| Configuration | Single 10" |
| Net Volume | 0.60 ft³ |
| Tuning Frequency | N/A — Sealed |
| External Dimensions | 24.5" W × 5.25" H × 13.5" D |
| Front Baffle Thickness | 1.5" Double Baffle |
| MDF | Langboard Elite 3/4" |
| Joinery | V-groove + dado |
| Terminal Cup | Recessed ABS/Carbon Fiber Composite |
| Speaker Wire | 12g OFC pre-installed |
| Finish | Plush Black |
| Vehicle Fitment | Universal |
| Brand + Model | Arc Audio A10 |
| Size | 10" |
| RMS Power | 250W |
| Peak Power | 500W |
| Voice Coil Config | Dual 2-ohm or Dual 4-ohm (select at checkout) |
| Mounting Depth | 3.77" |
| Cutout Diameter | 9-3/16" |
| Optimum Sealed Volume | 0.60 ft³ |
| Sealed Volume Range | 0.40 – 0.90 ft³ |
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.
| 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 |
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.
The modulus of elasticity measures panel stiffness — 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.
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.
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.
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.
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.
Hand-assembled at our facility in Tullahoma, TN. Every enclosure is inspected before it ships.
Internal volume and port geometry are calculated to spec and CNC-cut to exact dimensions. The box performs the same way every time.








