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 common chamber sealed wedge enclosure at 2.0 cubic feet net, 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: Is this common chamber or dual chamber?

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 common 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

Loaded Series | P12D-S W | Dual Chamber

Two Arc Audio X2V2 12s.
Dual Chamber Sealed Wedge, Loaded and Wired.

500 watts RMS total across two drivers, 1,028 square centimetres of cone, and two separate 1.0 cubic foot sealed chambers in a wedge cabinet that leans into a seat back rather than taking the whole cargo floor. Both drivers arrive mounted, wired and sealed against the baffle.

2.0Cu Ft Net Total

1.0Cu Ft Per Driver

500WRMS Total

15.1mmDriver Xmax

Loaded system. Two Arc Audio X2V2 12 subwoofers are included and pre-installed. Select your voice coil configuration and carpet above. An amplifier, power wire and RCA cables are not included.

Dual Chamber — A Full Divider, Not a Shared Box

Each driver gets its own sealed 1.0 cubic foot chamber, separated by a full divider. That is now standard across every Proline X sealed dual enclosure, and it is worth understanding why.

In a shared chamber, one cone's motion changes the air pressure the other driver is working against. At moderate levels you will not notice. Under hard excursion the pair starts to modulate each other and the middle of the output softens. With a divider, each driver sees only its own air spring, so the pair holds its character all the way up rather than getting vague when you ask for everything.

It also means there is no cross chamber wiring to fail and no shared leak path. If one chamber's seal is ever compromised, the other is unaffected.

1.0 cu ft Per Driver — Tighter Than Arc's Optimum

Arc Audio publishes a sealed range of 0.9 to 1.55 cubic feet per X2V2 12, with 1.15 as their optimum. Each chamber here is 1.0, sitting between their minimum and their optimum rather than at it. Same alignment as our single 12 wedge, and the same deliberate choice.

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 over a thousand square centimetres of cone between them, output is not the constraint on this build. Control is what you want from the alignment.

Work Out Your Impedance First

This is the step people get wrong on dual builds. Two dual voice coil drivers give you a lot of wiring options and only some of them land somewhere your amplifier will be happy.

Two D4 drivers can present 1, 4 or 16 ohms depending on 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 for a single monoblock. Decide the load you want, confirm your amplifier is stable at it, then select the coil variant to reach it. The drivers are installed and the cabinet sealed before it ships, so this is not something that can be changed afterwards.

Chambers

Two Sealed Chambers, One Cabinet

A full divider gives each driver its own 1.0 cubic foot. Neither driver modulates the air load the other one sees, so the pair stays predictable at high output.

Power

500W RMS Total, 250W Each

Arc rates conservatively. Their test method doubles power after each successful round until something fails, so 250 watts per driver is sustained thermal capacity rather than a peak figure.

Cone Area

1,028 cm² Between Two Drivers

Each X2V2 12 carries 514 cm² of cone and 15.1mm of one-way Xmax. Doubling cone area is the most efficient way to add output without asking either driver to work harder.

Baffle

Twin 11.13" Cutouts, 0.75" Baffle

Cut from Langboard Elite 3/4" MDF to the X2V2's 11.11 inch cutout requirement. Max mounting depth is 8.5 inches against the driver's 6.75 inch requirement.

Wiring

Pre-Wired 12g OFC

The recessed Proline X ABS and carbon fiber terminal cup with stainless hardware and copper ring terminals is installed and wired to both drivers. Connect your amplifier run and wiring is finished.

Geometry

28" Wide, Tapering 8.5" to 13.75"

The roughly 20 degree taper lets it lean into a seat back and keeps the baffle out of parallel with the rear glass. A square dual 12 cabinet at this volume would take the entire cargo floor.

Orientation

Shallow Edge Up, Deep Edge Down

At 28 inches wide it needs the full deep edge sitting flat on the floor to be stable. Mounted inverted it stands proud and puts the baffle back parallel with the glass.

Acoustic

Polyfill in Both Chambers

Fitted and matched to volume in each chamber before the cabinet is sealed. It makes each side behave acoustically larger than its physical volume, with consistent packing density on every unit.

Ready to Mount. Ready to Wire.

The system ships fully assembled. Both drivers are mounted, gasketed and sealed against the baffle, and wired to the Proline X terminal cup with 12 gauge OFC. Polyfill is installed in both chambers. Connect your amplifier run and the install is complete.

Impedance Options — D2 and D4

Two D4 drivers can present 1, 4 or 16 ohms. 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 for a single monoblock. Target 400 to 500 watts RMS total for the pair. Confirm what your amplifier is stable at before selecting the coil variant.

Where It Fits

At 28 inches wide and 14.5 tall, tapering from 8.5 to 13.75 inches deep, this needs a vertical surface to lean against and a wide flat run of floor:

Behind rear seats in SUVs and crossovers
Against a bulkhead in a large hatchback
Trunk front wall in a full size sedan
Crew cab trucks, behind the seat
Van rear walls and side panels
Wagon cargo areas against the seat back

1-Year Warranty

Proline X Performance Series enclosures carry a one-year limited warranty against defects in materials and workmanship. Built and inspected in our Tullahoma, Tennessee facility before shipment. Both Arc Audio X2V2 12 drivers carry their own one-year manufacturer warranty, handled through Arc Audio.

Made in Tennessee

Every Proline X enclosure is CNC cut and hand assembled in Tullahoma, Tennessee on ShopSabre routers. Internal volume, chamber divider placement, cutout geometry, wedge angle and terminal positioning are held to spec on every unit. Langboard Elite MDF throughout, named, mill documented, with published density and internal bond specifications.

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

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.