Proline X

Proline X P12D-S W | Dual 12" Sealed Wedge Subwoofer Enclosure | Loaded with Arc Audio X2V2 12

Q: What comes in this system?

A Proline X P12D-S W dual chamber sealed wedge enclosure at 2.0 cubic feet net, 1.0 cubic feet per driver behind a full divider, with two Arc Audio X2V2 12 subwoofers already mounted, gasketed and sealed against the baffle in your chosen D2 or D4 configuration. Prewired with 12 gauge OFC to a recessed Proline X terminal cup, polyfill installed. Choose dark gray trunkliner or plush black above. An amplifier, power wire and RCA cables are not included.

Q: What impedance will this present to my amplifier?

That depends on the coil variant and how the pair is wired. Two D4 drivers can present 1, 4 or 16 ohms depending on the configuration. Two D2 drivers can present 0.5, 2 or 8 ohms. Series parallel on a pair of D4s at 4 ohms is the most common safe choice. Work out the load you want first, confirm your amplifier is stable at it, then select the coil variant to reach it. Our wiring diagram generator will show you the options.

Q: How much amplifier power do I need?

Target 400 to 500 watts RMS total for the pair. Each X2V2 12 is rated at 250 watts RMS continuous, so 500 watts total is the ceiling. Stay in that range rather than chasing the 500 watt per driver peak figure. A clean amplifier at rated power will outperform a clipping one at double it, and with two drivers sharing one chamber a clipped signal is felt across both.

Q: How is the internal volume divided?

Dual chamber. A full divider gives each driver its own sealed 1.0 cubic foot chamber, 2.0 cubic feet total. Each driver loads independently, so one cone's motion does not modulate the air load the other one sees under hard excursion. That is why the pair holds its character at high output rather than getting soft in the middle, and it is now standard across all Proline X sealed dual enclosures.

Q: Which way round does the wedge mount?

Shallow edge up, deep edge on the floor, leaning back into the seat back or bulkhead. At 28 inches wide it needs the full deep edge sitting flat to be stable. Mounted the other way round it stands proud, wastes the space it exists to save, and puts the baffle back parallel with the glass.

Q: Why 2.0 cubic feet for two drivers?

Each driver gets its own sealed 1.0 cubic foot chamber, which sits between Arc Audio's published minimum of 0.9 and their optimum of 1.15. A tighter sealed volume raises system Qtc, producing more midbass punch and tighter transient control at the cost of the deepest anechoic extension. With two 12s moving 1,028 square centimetres of cone between them, output is not the constraint. Control is what you want from the alignment.

Q: What is the warranty on this system?

The enclosure carries a 1 year limited warranty on craftsmanship and materials, which is the standard across the Performance and Performance Optimized lines. Micro Series and Professional Series enclosures carry 2 years. Both Arc Audio X2V2 12 drivers carry their own 1 year manufacturer warranty separately, handled through Arc Audio.

Q: How should a cabinet this size be secured?

Properly, and plan it before the box goes in the vehicle. Loaded with two 12s this is a two person lift carrying serious mass, and a cabinet this heavy loose in a cargo area is a genuine safety problem in a hard stop rather than a rattle to be managed. Anchor it to factory tie down points or through bolt to the floor pan. Do not rely on a single strap over the top.

SKU: P12D-S W ARC X2V2 D4 G

QUICK SPECS

Best For: High output builds where a square dual box would eat the whole floor
Configuration: Dual 12" Sealed Wedge, Performance Series, loaded
Volume: 2.0 ft³ Net total, 1.0 ft³ per driver, separate chambers
Tuning: N/A, Sealed
Sonic Character: Warm, punchy, midbass forward

Proline X Enclosure: Built in Tennessee CNC-cut Langboard Elite 3/4" MDF, V-groove + dado joinery, recessed ABS/Carbon Fiber terminal cup.

Driver + Enclosure: Matched and Pre-Wired Subwoofer pre-installed and wired to the correct impedance. Connect your amplifier and it's ready to run.

Shipping Included No freight charges at checkout on orders to the lower 48. Alaska, Hawaii, and international orders are quoted live rates at checkout.

$ 599.99

Impedance

Hurry! Only 4 left in stock.

Financing available. Choose Shop Pay Installments at checkout.

What's Included

Proline X P12D-S W sealed wedge enclosure, dual 12 inch, 2.0 cu ft net dual chamber
Two Arc Audio X2V2 12 subwoofers pre-installed in your chosen D2 or D4 configuration
Pre-wired 12 gauge OFC speaker wire to the terminal cup
Recessed Proline X ABS and carbon fiber terminal cup with stainless hardware and copper ring terminals
Polyfill installed and matched to this volume
Your choice of dark gray trunkliner or plush black carpet

Amplifier, power wire and RCA cables are not included.

Proline X P12D-S W | Dual 12" Sealed Wedge Subwoofer Enclosure | Loaded with Arc Audio X2V2 12

Enclosure Type Sealed

External Dimensions 28" (W) x 14.5" (H) x 8.5" top / 13.75" bottom (D)

Net Volume 2.0 cu ft

Tuning Frequency N/A - Sealed

Cutout Diameter 11.13" x2

Front Panel Thickness 0.75" Single Baffle

Max Mounting Depth 8.5"

INSTALLER'S TAKE

Work out your final impedance before you order, not after. Two dual voice coil 12s give you a lot of wiring options and only some of them land somewhere your amplifier will be happy. Series parallel on a pair of D4s gives you 4 ohms, all parallel gives you 1 ohm, and there are several combinations in between. Decide the load first, then pick the coil variant to reach it. The drivers are installed and the cabinet is sealed before it ships, so this is not something we can change later.

Mount it shallow edge up, leaning back into the seat or bulkhead. At 28 inches wide this is a large cabinet and it needs the full deep edge sitting flat on the floor to sit stably. Measure the width across your seat back before ordering, because a dual 12 wedge that will not sit flush is worse than a smaller box that does.

Loaded with two 12s this is a two person lift and it carries serious mass. Anchor it to factory tie down points or through bolt to the floor pan. A cabinet this heavy loose in a cargo area is a genuine safety problem in a hard stop, not a rattle to be managed. Plan the tie down before the box goes in the vehicle rather than after.

Product Details

Proline X P12D-S W Dual Chamber Sealed Wedge, Loaded

Cut and tuned for a pair of Arc Audio X2V2 12 drivers

V-Groove and Dado Langboard Elite MDF 2.00 cu ft Net Fits Arc Audio X2V2 12

2.00cu ft net

0.918system Qtc

41 HzF3 rolloff

6.75 inX2V2 12 mounting depth

Built Around the Arc Audio X2V2 12

Nothing about this box is generic. Every layer is cut to the X2V2 12's published sealed target, with the baffle bored to the X2V2 12's 11.11 in cutout, and clearance cut for its 6.75 in mounting depth.

The X2V2 12 carries a published Fs of 25.57 Hz, Qts of 0.471 and Vas of 79.36 litres, and an EBP of 49, which puts it in sealed enclosure territory. We ran the alignment math on that data and built the box to land where it belongs.

Two Drivers, Two Sealed Chambers

A full divider splits this cabinet down the middle. Each X2V2 12 gets its own 1.00 cubic foot sealed volume, 2.00 cubic feet total. Neither driver sees the other's back pressure, so the pair behaves like two matched single builds rather than one shared chamber.

True net, not marketing net. Internal volume is calculated by summing each CNC cut layer's opening, not estimated from external dimensions minus wall thickness.

Proline X Performance Series Construction

This enclosure is 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. The panels are V-grooved and folded on the seam, then dadoed where the internal bracing lands, so every joint is a mechanical lock rather than a glue line under load.

Pre-Wired Terminal Cup

Proline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, pre-wired internally with 12 gauge OFC. No CCA anywhere in the build.

Damped and Finished

Polyfill is pre-installed to smooth the in box response, and the shell is wrapped in plush black carpet. Built in Tullahoma, Tennessee.

Enclosure Only or Loaded

Order the enclosure bare and mount your own pair of X2V2 12 drivers, or order it loaded and we mount the drivers, dress the wiring and ship it ready to bolt in.

Sealed Enclosure Performance: Pre-Calculated

Using the published Thiele Small parameters for the Arc Audio X2V2 12, here is the predicted Qtc, system resonance (Fc) and F3 rolloff for this enclosure. Calculated with the same formulas as the Audio Intensity Sealed Box Calculator.

Arc Audio X2V2 12 D2 | Qts 0.471 | Fs 25.57 Hz | Vas 79.36 L

Enclosure Size	Qtc	Fc	F3
1.00 cu ft per chamber, 2.00 cu ft total	0.918	49.9 Hz	40.9 Hz

Arc Audio X2V2 12 Frequency Response | Sealed, 1.00 cu ft

1.00 cu ft (Qtc 0.918) -3dB reference

Note on coil choice: The figures above are the D2 set. The D4 X2V2 12 carries Qts 0.543 and Vas 82.65 litres, which in this same 1.00 cubic foot volume lands at Qtc 1.075, Fc 50.6 Hz and F3 38.6 Hz. Worth accounting for if you are choosing between the two. Run your own numbers in the Sealed Box Calculator.

Cut for the Driver, Not the Catalog

Select your configuration above. This enclosure ships free to the lower 48 with a 1 year limited warranty, built one at a time in Tullahoma, Tennessee. Ordered loaded, the X2V2 12 carries its own 1 year manufacturer warranty through authorized dealers.

Enclosure Specifications

Enclosure	Proline X P12D-S W, Performance Series sealed wedge
Driver	Two Arc Audio X2V2 12, pre-installed
Voice Coil	Dual, available D2 or D4
Material	Langboard Elite MDF, 3/4" (18mm)
Enclosure Type	Sealed
Chamber	Dual chamber, full divider
Net Internal Volume	2.0 ft³ total, 1.0 ft³ per driver
Tuning Frequency	N/A: Sealed
External Width	28"
External Height	14.5"
External Depth (Top)	8.5": shallow end
External Depth (Bottom)	13.75": deep end
Wedge Angle	~20° taper
Subwoofer Cutout	11.13" x2
Max Mounting Depth	8.5"
Front Panel Thickness	0.75" Single Baffle
Finish	Dark Gray Trunkliner or Plush Black
Terminal Cup	Proline X ABS/Carbon Fiber, recessed mount, stainless hardware, copper ring terminals
Wiring	Pre-wired 12g OFC speaker wire
Polyfill	Installed
Built	Tullahoma, Tennessee
Warranty	1-Year Limited on the enclosure

Performance Graphs

Woofer Details

Two Arc Audio X2V2 12s. Each is rated at 250 watts RMS continuous and 500 watts peak, with 15.1mm of one-way linear Xmax, an Fs of 25.57 Hz, and a 514 square centimetre cone. Arc rates conservatively: their test philosophy is to double test power after each successful round until something actually fails, so the 250 watt figure per driver reflects sustained thermal capacity rather than a peak dressed up as continuous. The motor uses double stacked magnets and a 2 inch copper coated aluminium voice coil on a Kapton former, anodised black for radiative heat dissipation. The four spoke stamped steel basket carries eight integrated motor cooling vents plus a T-yoke centre vent. Construction is built for daily use: a moisture coated reinforced pulp cone, a large diameter rubber surround rather than foam, and a high roll Conex spider with the tinsel leads woven directly into it. Qts differs between coil options, 0.471 on the D2 and 0.543 on the D4.

Brand + Model	Arc Audio X2V2 12 (x2)
Size	12" each
RMS Power	250W each, 500W total
Peak Power	500W each
Voice Coil Config	Dual 2 ohm or Dual 4 ohm
Voice Coil Diameter	2"
Xmax	15.1mm one-way linear
Fs	25.57 Hz
Qts	0.471 (D2) / 0.543 (D4)
Sensitivity	85.95 dB
Frequency Response	25–500 Hz
Cone Area (Sd)	514 cm² each
Mms	176.4 g
Mounting Depth	6.75"
Cutout Diameter	11.11"
Driver Warranty	1-Year through Arc Audio

Why This Combo Works

Two Arc Audio X2V2 12s in a Proline X Dual Chamber Sealed Wedge

Arc Audio publishes a sealed range of 0.9 to 1.55 cubic feet per X2V2 12, with 1.15 as their optimum. This cabinet gives each driver its own sealed 1.0 cubic foot chamber, 2.0 cubic feet total, separated by a full divider. That sits between Arc's minimum and their optimum, the same alignment as our single 12 wedge, and it is a deliberate choice rather than a compromise.

Separate chambers matter more than people expect on a dual build. Each driver loads independently, so one cone's motion does not modulate the air load the other one sees under hard excursion. A pair sharing one chamber stays predictable at moderate levels and gets progressively softer in the middle as output rises. Divided, they hold their character all the way up.

A tighter sealed volume raises system Qtc, producing more midbass punch and tighter transient control at the cost of the deepest anechoic extension. With two drivers moving 1,028 square centimetres of cone between them, output is not the constraint here. Control is what you want, and that is what this volume and this divider give you.

The wedge geometry does the rest. At 28 inches wide and tapering from 8.5 to 13.75 deep, it leans into a seat back and leaves the flat cargo floor usable, where a square dual 12 cabinet would take the lot. For amplifier power, target 400 to 500W RMS total for the pair, and work out your final impedance carefully before ordering.

Materials

Material

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.

Specifications

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

Internal Bond

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.

Stiffness

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.

Screw Holding

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.

Sourcing

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.