Proline X PO 15D-S W VCW sealed wedge, front baffle with gloss black insert and pre-wired leads, 36 by 18 inches.

Proline X

Performance Optimized Wedge Sealed Dual 15" Enclosure | NVX VCW15v3

Q: Does this fit the NVX VCW15v3, and will any other 15 inch fit?

The VCW154v3 (D4), yes. The baffle is cut to 14.12 in, NVX's published cutout, under the 15.59 in frame. The 8.19 inch motor clears the cabinet with 5.05 inch to spare. This box is for the VCW154v3 (D4). The VCW152v3 D2's higher Qts reads Qtc 0.98 in the same 2.00 cubic feet, boomy rather than tight, so we do not recommend it here.Any other 15, no. The airspace is worked out from the VCW15v3's own Qts and Vas, and a different woofer that happened to drop into the hole would not see the alignment printed on this page.

Q: Why 2.00 cubic feet per chamber, and what alignment does it target?

2.00 cubic feet is the Butterworth volume on the D4 figures (Fs 31.3 Hz, Qts 0.45, Vas 82.9 liters): Qtc 0.706, half power at 49.2 Hz. This box is for the VCW154v3 (D4). The VCW152v3 D2's higher Qts reads Qtc 0.98 in the same 2.00 cubic feet, boomy rather than tight, so we do not recommend it here.NVX's manual and product pages are the only published source for this driver, so treat the Qtc as good to a few hundredths.

Q: What amplifier power should I run, and how should I wire it?

NVX rates the VCW15v3 at 1500 watts RMS per driver, so target 1050 to 1500 watts RMS per driver at the final load.A pair of VCW154v3 (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. Confirm your amplifier's minimum stable impedance first.

Q: Why the wedge angle, and why rear-firing into the trunk?

The seat-side face carries a 20 degree rake that matches the lean of a factory rear seat back, so the cabinet sits flush against it and the cargo space in front stays usable. The baffle is the vertical trunk-lid-side face, so the drivers fire rearward into the trunk cavity.The trunk acts as an acoustic extension for the sealed box, and the cabin adds real output below 50 Hz, so in-vehicle response runs deeper than the anechoic 49.2 Hz on this page.

Q: Why two separate chambers instead of one shared volume?

Two drivers sharing one sealed volume load each other: each driver's compression stroke becomes the pressure the other works against, which blurs the alignment either would have alone. A bonded full-height 3/4 inch divider gives each driver its own 2.00 cubic feet and its own polyfill.It also means a failure in one driver does not unload the other, and the alignment on this page is the alignment in each chamber, not an average across a shared box.

Q: What is the expected low-frequency extension?

Anechoic F3 is 49.2 Hz per chamber on the D4, with system resonance at 49.1 Hz. At Qtc 0.71 the response is maximally flat into the rolloff, so F3 and fc coincide.Those figures exclude cabin gain. In a car the cabin's transfer function adds real output below 50 Hz, so in-vehicle response runs deeper than the numbers above.

Q: Do I need to add polyfill or damping?

No. Polyfill is already installed in both chambers as a light wall lining to control internal reflections, and the quantity is chosen so it does not change the acoustic volume.Do not add more. Packing a sealed box with fill makes it behave as though it were larger, which walks the alignment away from the 2.00 cubic feet per chamber this cabinet was built to.

Q: Is the driver included, and are the threaded inserts installed?

No driver. This is an enclosure only. You receive the cabinet finished in plush black carpet with the gloss black acrylic baffle insert, one side-mounted pre-wired terminal cup to both positions, the polyfill lining already in place, and threaded inserts pressed on NVX's published 14.78 inch bolt circle with stainless machine screws.The pair of NVX VCW15v3 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 15 inch box.

SKU: PO 15D-S W VCW BB

QUICK SPECS

Best For: Dual NVX VCW15v3 Trunk-Fit Builds
Net Volume: 2.00 cu ft per chamber (4.36 cu ft Gross Total)
Driver Match: Pair of NVX VCW15v3 (VCW154v3 D4), matched
Construction: Dual Chamber | Rear-Firing Wedge | V-Groove/Dado | Double 1.5" Baffle | 1 Shared Terminal Cup | Threaded Inserts

Shipping Included No freight charges at checkout. What you see is what you pay.

Built in Tennessee CNC cut from 3/4" Langboard Elite MDF. V-groove and dado joinery.

Advanced Terminal Cup Built in-house. ABS/Carbon Fiber. Stainless steel hardware. Copper ring terminals.

$ 499.99

Acrylic Insert Color

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Performance Optimized Wedge Sealed Dual 15" Enclosure | NVX VCW15v3

More enclosures cut for NVX subwoofers: NVX Subwoofer Boxes

Enclosure Type Sealed

External Dimensions 36.00" W x 18" H x 19.90" D at base tapering to 13.35" D at top

Gross Volume 4.36 cu ft

Net Volume 4.00 cu ft

Shipping Weight 72 lbs

Front Panel Thickness 1.5"

INSTALLER'S TAKE

2.00 cubic feet per chamber, Qtc 0.706 on the D4. This box is for the VCW154v3 (D4). The VCW152v3 D2's higher Qts reads Qtc 0.98 in the same 2.00 cubic feet, boomy rather than tight, so we do not recommend it here.

Two chambers at 2.00 each, 36.00 wide, 18 tall, 19.90 at the base. Wire the pair identically.

Cut is 14.12, NVX's own figure, and the inserts are already pressed on their 14.78 bolt circle. It is sealed, so leave the polyfill as it is and run it at 1500 watts or under.

Product Details

Performance Optimized Wedge | Dual NVX VCW15v3

Dual 15" Sealed Wedge Enclosure | Rear-Firing Trunk-Load Design

2.00 ft3 Net per Chamber4.36 ft3 GrossQtc 0.71Two Separate Chambers36.00" x 18" x 13.35/19.90"Built in Tennessee

A Pair of NVX VCW15v3 in a Sealed Wedge

The VCW15v3 is NVX's 15 inch: 1500 watts RMS, 23 mm of one-way excursion on 804 square centimeters of cone, and 8.19 inches of mounting depth. Every figure comes from NVX's owner's manual and product pages for the VCW154v3, including the 0.130 cubic foot driver displacement and the bolt circle, so nothing here is estimated.

2.00 cubic feet net per chamber is the Butterworth volume on the D4 figures, Fs 31.3 Hz, Qts 0.45 and Vas 82.9 liters: Qtc 0.706, half power at 49.2 Hz. This box is for the VCW154v3 (D4). The VCW152v3 D2's higher Qts reads Qtc 0.98 in the same 2.00 cubic feet, boomy rather than tight, so we do not recommend it here.

Two Fully Separate Chambers

A bonded full-height 3/4 inch MDF divider splits the cabinet into two sealed chambers of 2.00 cubic feet net each, so every driver sees exactly the airspace printed on this page. Two drivers sharing one volume load each other; the divider removes that, and each chamber carries its own polyfill.

The cabinet is 36.00 inches wide, 18 tall, 13.35 inches deep at the top and 19.90 at the base. One shared side-mounted terminal cup feeds both driver positions.

Trunk-Load Wedge Design Explained

The drivers mount on the vertical trunk-lid-side face and fire rearward into the trunk cavity.

Seat-Side Face Matches Seat Lean

Angled face matches the roughly 20 degree factory seat lean.

Trunk-Lid-Side Face Fires the Woofer

Vertical baffle, cone firing rearward into the trunk cavity.

Trunk Cavity Loading

The trunk acts as an acoustic extension for a smoother presentation.

Preserves Trunk Cargo Space

The wedge tucks against the seat back and the space in front stays usable.

Engineered for a pair of NVX VCW15v3

Half power lands at 49.2 Hz anechoic on the D4, before any cabin gain. NVX publishes a driver displacement of 0.130 cubic feet, and it is taken out of the net figure.

Alignment Numbers (Per Chamber)

Driver (per chamber)	System Qtc	fc	F3
VCW154v3 dual 4 ohm	Qtc 0.706	49.1 Hz	49.2 Hz

Mounting Geometry

The baffle is cut to 14.12 in, NVX's published cutout, under the 15.59 in frame. The rear panel rakes 20 degrees, so the cavity deepens from 13.35 in at the top to 19.90 in at the base, and the 8.19 in motor clears it with 5.05 in to spare. NVX publishes the 14.78 in bolt circle for the VCW15v3, so the threaded inserts are pressed at the shop and the stainless machine screws are in the box: set the driver in the recess and bolt it down.

What the Numbers Rest On

Langboard Elite MDF

Premium 3/4 in MDF throughout.

V-Groove and Dado Joinery

CNC cut V-grooves at every panel intersection, sides and divider seated in dados.

Double-Layer 1.5" Front Baffle

Two bonded 3/4 in MDF sheets at the driver face, the outer layer machined as a flush recess.

NVX's Published Parameters

VCW154v3 (D4): Fs 31.30 Hz, Qts 0.450, Qes 0.620, Qms 1.68, Vas 82.90 L, Sd 804 cm2.

Wiring a pair of NVX VCW15v3 to Your Amplifier

A pair of VCW154v3 (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. Confirm the final load against your amplifier's minimum stable impedance before powering the system.

Power handling is 1500 watts RMS per driver, 3000 across the pair. Aim for roughly 1050 to 1500 watts per driver at the impedance you wire.

Built in Tennessee, Backed by Audio Intensity

Cut and assembled in Tullahoma, Tennessee on our own CNC equipment. Finished in plush black carpet with the gloss black acrylic baffle insert, one shared pre-wired terminal cup, 12 gauge OFC to both driver positions. Polyfill wall lining installed. Threaded inserts pressed on NVX's published bolt circle, stainless machine screws in the box. 1 year limited warranty. Enclosure only, the drivers are purchased separately. Call or text 931-563-5151.

Dual NVX VCW15v3: Cut for the Driver

2.00 cubic feet net per chamber at Qtc 0.706, F3 49.2 Hz on the D4, cut direct fit and built to order in Tennessee.

Specifications

Specification	Value
Series	Proline X Performance Optimized Wedge
Compatible Driver	NVX VCW15v3 (VCW154v3 D4), quantity 2. Direct fit
Configuration	Dual 15 inch, two separate chambers, sealed wedge
Mounting Position	Trunk or cargo area, tall face against the rear seat back
Firing Direction	Rearward into the trunk. Not a down fire design, no feet included
External Width	36.00 in
External Height	18 in at the seat face
External Depth	19.90 in at the base, tapering to 13.35 in at the top
Internal Volume, Gross	4.36 cu ft total
Internal Volume, Net Acoustic	2.00 cu ft per chamber after the divider and the 0.130 cu ft displacement NVX publishes per driver
Driver Mounting Depth	8.19 in required; 5.05 in clearance above the motor against the raked rear panel
Alignment, D4 per chamber	Qtc 0.706, fc 49.1 Hz, F3 49.2 Hz anechoic
Woofer Opening	14.12 in, two, NVX's published cutout
Frame Outer Diameter	15.59 in, NVX published
Bolt Circle	14.78 in, NVX published; threaded inserts pre-installed
Driver Displacement	0.130 cu ft, NVX published
VCW154v3 (D4) Fs / Qts / Qes / Qms / Vas	31.30 Hz / 0.450 / 0.620 / 1.68 / 82.90 L
Driver Sd	804 cm2, published by NVX
Xmax	23 mm one way, NVX spec
Driver Power Handling	1500 W RMS per driver, NVX spec
Wiring Options	A pair of VCW154v3 (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.
Parameter Source	NVX VCW154v3 owner's manual and nvx.com product pages
Material	Langboard Elite MDF
Construction	CNC cut, V-groove and dado joinery
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 inserts pre-installed on the published bolt circle, stainless machine screws included
Terminal Cups	One Proline X ABS and carbon fiber composite, side mounted, pre wired 12 gauge OFC to both driver positions
Acrylic Insert	Gloss black acrylic baffle insert standard; None variant minus $20
Damping	Light polyfill wall lining in both chambers, does not alter acoustic volume
Carpet	Plush black
Shipping Weight	72 lb
Warranty	1 Year Limited
Built In	Tullahoma, Tennessee

Performance Graphs

Net airspace

2.00

cu ft per chamber

System Qtc

0.71

sealed

Half power

49.2

Hz · F3

Xmax at

2244

W RMS · no filter

With 25 Hz subsonic

2914

W RMS · +30%

Amplifier

1500

W RMS recommended

This enclosure holds 2.00 cu ft net per chamber. In it the NVX VCW15v3 runs a system Qtc of 0.71 with half power at 49.2 Hz, and the cone reaches its 23.0 mm travel limit at 2244 W, above the driver’s 1500 W thermal rating, so heat stops you before travel does. Run a subsonic filter at 25 Hz and that becomes 2914 W — +670 W, or 30 percent more power for the same 23.0 mm of travel.

01Is it a sealed driver?

Efficiency bandwidth product places the motor before anything else is decided.

EBP = Fs ÷ Qes = 50.5

dual 4 ohm · EBP 50.5

At 50.5 the VCW15v3 sits in the transition band, not the sealed band. That is not a mismatch: a transition motor works in either alignment, and sealed buys a smaller box and a gentler roll-off at the cost of some low-end output. Stage 02 shows what this airspace actually does with it.

02What the box does to it

2.00 cu ft against a 82.9 L Vas.

α = Vas ÷ Vb = 1.46 · Fc = Fs√(α+1) = 49 Hz · Qtc = 0.71

dual 4 ohm · Qtc 0.71, Fc 49 Hz, F3 49.2 Hz

The box lifts resonance from 31.3 Hz free-air to 49 Hz and half power lands at 49.2 Hz, anechoic, before any cabin gain. Figures are NVX’s published VCW15v3 parameters from its owner’s manual and product pages, displacement included (0.130 cubic feet). This box is for the VCW154v3 (D4). The VCW152v3 D2’s higher Qts reads Qtc 0.98 in the same 2.00 cubic feet, boomy rather than tight, so we do not recommend it here. Each chamber holds 2.00 cubic feet, so these figures are per driver.

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 23.0 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

P_Xmax = 2244 W unfiltered → 2914 W with a 25 Hz subsonic

dual 4 ohm · 2244 W, no filterdual 4 ohm · 2914 W with subsonic at 25 Hz, 24 dB/octXmax 23.0 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 23.0 mm. Unfiltered that is 2244 W, reached first at 20 Hz. It sits above the 1500 W the driver can take thermally, so the voice coil gives up before the suspension does. The dashed traces are the same driver behind a subsonic filter at 25 Hz, 24 dB/oct: stopping the cone wasting travel below the passband lets it take 2914 W before hitting the same 23.0 mm. That is 30 percent more amplifier for the price of one filter setting.

Param	Value	Unit	Note
Fs	31.30	Hz	free-air resonance
Qts	0.450		dual 4 ohm
Vas	82.90	L	equivalent compliance
Sd	804.2	cm²	effective piston area
Xmax	23	mm	one-way linear travel
Pe	1500	W	continuous RMS
SPL	88.0	dB	1 W / 1 m, derived from T/S

Driver parameters as published by NVX VCW15v3 owner’s manual. Curves computed against this enclosure’s actual net airspace.

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.