Proline X
Performance Optimized Down Fire Wide Sealed 10" Enclosure | NVX NSW10v3
SKU: PO 10-S DFW NSW
- Alignment: 1.024 cu ft net. D2 Qtc 0.645, Fc 48.9 Hz, F3 54.1 Hz; D4 Qtc 0.687, Fc 46.9 Hz, F3 48.4 Hz; height set by motor clearance
- Down Fire Wide: 41"W x 12"D x 6.875"H in down fire position, 3" shallower and 11" longer than the standard 30 x 15, for under rear seats and narrow cargo floors
- Driver: NVX NSW10v3 (NSW102v3 D2 or NSW104v3 D4), 500 W RMS, 12.5 mm Xmax, 5.36 in mounting depth, 8.97 in cutout
- Build: Windowed U-brace, 1.5" double baffle, one side-mounted terminal cup, 12g OFC
- Standoffs: 1.75", ship uninstalled. Installed height 8.625"
Financing available. Choose Shop Pay Installments at checkout.
Performance Optimized Down Fire Wide Sealed 10" Enclosure | NVX NSW10v3
More enclosures cut for NVX subwoofers: NVX Subwoofer Boxes
Proline X Performance Optimized Down Fire Wide 10" Sealed
Under rear seat and narrow cargo floor fitment. Cut for the NVX NSW10v3
The Down Fire Wide Format
Down Fire Wide answers a specific space problem. The floor under the rear seat of a truck or SUV, and many narrow cargo floors, is long and shallow, and a standard 30 by 15 inch enclosure will not go in it.
So the cabinet is turned sideways. This one runs 41 inches wide by 12 inches deep by 6.875 inches tall, measured in the down fire position. Against our standard 30 by 15 inch NSW10v3 cabinet it takes the same NSW10v3 driver, sits 3 inches shallower front to back and runs 11 inches longer. The airspace lost from the depth is recovered along the length, so the driver still gets a properly sized chamber rather than a compromised one.
Which one to choose. If you have 15 inches of depth, the standard 30 by 15 cabinet is the pick: it is shorter end to end and easier to place. Choose this one when depth is the limiting dimension and you have 41 inches of run. Measure the depth first; under seat spaces vary widely between cab configurations.
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 cutout, the mounting depth and the chamber volume all come from the NVX NSW10v3's own numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.
Built Around the NVX NSW10v3
The baffle is cut to 8.97 inches, NVX's published cutout, under the 10.40 inch frame, and the cabinet height is set by the driver's 5.36 inch mounting depth. The frame is round and sits on the 12 inch deep baffle with material to spare.
The NSW10v3 is NVX's 10 inch, rated 500 watts RMS, with 12.5 mm of excursion. It is 5.36 inches deep, which matters on a down fire, where the motor rises into the cabinet. It ships as the NSW102v3 (dual 2 ohm) and the NSW104v3 (dual 4 ohm), and every figure comes from NVX's owner's manual and product pages for those two models, including the displacement and the 9.68 inch bolt circle.
NVX publishes the bolt circle, 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.
Net Volume and Alignment
The chamber holds 1.024 cubic feet net, from 1.082 cubic feet gross after 0.050 cubic feet of driver displacement, published by NVX.
One cabinet serves both coils. NVX publishes a separate parameter set for each: the NSW102v3 at Fs 38.67 Hz, Qts 0.510 and Vas 17.37 L, the NSW104v3 at Fs 36.91 Hz, Qts 0.540 and Vas 17.89 L. In this chamber they land as follows.
| Driver | System Qtc | Fc | F3, anechoic |
|---|---|---|---|
| NSW102v3, dual 2 ohm | Qtc 0.645 | 48.9 Hz | 54.1 Hz |
| NSW104v3, dual 4 ohm | Qtc 0.687 | 46.9 Hz | 48.4 Hz |
Height here is set by the driver's mounting depth, not by the airspace. The 5.36 inch motor rises off the baffle into the cavity and needs 0.75 inch of clearance above it, and the cabinet cannot be built lower than that. At that height the 41 by 12 footprint holds 1.024 cubic feet net, more than the 0.93 cubic feet the standard 30 by 15 box was built to. The extra air lowers Qtc and eases the rolloff, which is the safe direction for a sealed alignment. It is a consequence of motor clearance, not a design target.
Both coils sit below the 0.707 reference, so the rolloff is gentle rather than peaked. NVX does not publish a position on down firing this driver, and this cabinet makes no claim on their behalf; the standoffs ship uninstalled, so front firing or up firing is a decision you can make at install time.
True net, not marketing net. Internal volume is calculated from the machined cavity dimensions and the driver displacement, not estimated from external dimensions minus wall thickness. All figures are anechoic; firing down into the floor, the sealed rolloff meets rising cabin gain below 60 Hz and in-car response extends well below them.
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 6.875 inches tall, measured in the down fire position. The 1.75 inch standoffs ship with the enclosure but are not installed, so plan the space around an installed height of 8.625 inches if you use them.
1.5 Inch Double Baffle
Two 3/4 inch layers laminated to 1.5 inches, with the outer layer machined as a flush recess so the driver bolts to the inner layer on 8/32 threaded inserts. Stainless machine screws included.
Windowed U-Brace
A windowed U-brace dadoed to the shell ties the long 41 inch panels together without closing off the chamber. Polyfill is installed as a light wall lining.
Side-Mounted Terminal Cup
One Proline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, side mounted and pre-wired in 12 gauge OFC, so it stays accessible with the baffle facing the floor.
Power and Wiring
NVX rates the NSW10v3 at 500 watts RMS. Target 350 to 500 watts RMS at the final load.
The NSW102v3 (D2) wires to 4 ohms with its coils in series or 1 ohm in parallel. The NSW104v3 (D4) wires to 8 ohms in series or 2 ohms in parallel. Anything under 1 ohm, and many amplifiers at 1 ohm, is outside what the amplifier is built for; series wiring is the safe default. Confirm the load against your amplifier's minimum stable impedance before powering the system.
Bring your own NVX NSW10v3; the driver is purchased separately. The enclosure carries a 1 year limited warranty. Plush black carpet.
Cut for the Driver, Not the Catalog
Down Fire Wide, built for the space under a rear bench, one at a time in Tullahoma, Tennessee. Questions on fitment or amplifier matching, call 931-563-5151.
| Specification | Value |
|---|---|
| Series | Proline X Performance Optimized Down Fire Wide |
| Compatible Driver | NVX NSW10v3 (NSW102v3 D2 or NSW104v3 D4), quantity 1. Direct fit |
| Enclosure Type | Sealed, single driver, down fire, floor coupled |
| Intended Fitment | Under the rear seat of trucks and SUVs and narrow cargo floors, where depth is the limiting dimension |
| Firing Direction | Down firing, driver fires toward the floor. Standoffs ship uninstalled, so front or up firing is also possible |
| Chamber Configuration | Single sealed chamber, windowed U-brace, one side-mounted terminal cup |
| External Width | 41 in |
| External Depth | 12 in |
| External Height | 6.875 in in the down fire position, excludes standoffs |
| Installed Height | 8.625 in with the 1.75 in standoffs |
| Standard 30 x 15 Equivalent | 30 x 15 x 6.86 in, 0.93 cu ft net. Same driver, deeper and shorter footprint |
| Internal Volume, Gross | 1.082 cu ft |
| Net Volume | 1.024 cu ft after displacement |
| Height Set By | Driver clearance: the 5.36 in motor, 0.75 in minimum above it |
| Clearance Above Motor | 0.77 in |
| Alignment, D2 | Qtc 0.645, Fc 48.9 Hz, F3 54.1 Hz anechoic |
| Alignment, D4 | Qtc 0.687, Fc 46.9 Hz, F3 48.4 Hz anechoic |
| Woofer Opening | 8.97 in, NVX's published cutout |
| Frame Outer Diameter | 10.40 in, NVX published |
| Bolt Circle | 9.68 in, NVX published; threaded inserts pre-installed |
| Driver Mounting Depth | 5.36 in |
| NSW102v3 (D2) Fs / Qts / Qes / Qms / Vas | 38.67 Hz / 0.510 / 0.548 / 7.32 / 17.37 L |
| NSW104v3 (D4) Fs / Qts / Qes / Qms / Vas | 36.91 Hz / 0.540 / 0.612 / 4.59 / 17.89 L |
| Driver Sd | 340 cm2, published by NVX |
| Xmax | 12.5 mm, NVX spec; the manual does not state one-way or peak to peak |
| Driver Power Handling | 500 W RMS, NVX spec |
| Wiring Options | D2: 4 ohm series or 1 ohm parallel. D4: 8 ohm series or 2 ohm parallel. Series is the safe default |
| Parameter Source | NVX NSW102v3 / NSW104v3 owner's manual and nvx.com product pages |
| Driver Displacement | 0.050 cu ft, published by NVX |
| Material | Langboard Elite MDF |
| Construction | CNC cut on ShopSabre routers, 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 | Windowed U-brace, dadoed to the shell |
| Corner Profile | Square, Down Fire series standard |
| Driver Mounting | 8/32 threaded inserts, stainless machine screws included |
| Terminal Cup | One Proline X ABS and carbon fiber composite, side mounted |
| Internal Wiring | 12 gauge OFC |
| Standoffs | Included, 1.75 in, shipped uninstalled |
| Damping | Polyfill pre-installed as a light wall lining |
| Carpet | Plush Black |
| Bundle Options | Enclosure only, bring your own NSW10v3 |
| Warranty | 1 Year Limited |
| Built In | Tullahoma, Tennessee |
01Is it a sealed driver?
Efficiency bandwidth product places the motor before anything else is decided.
02What the box does to it
1.024 cu ft against a 17.4 L Vas.
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 12.5 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 38.67 / 36.91 | Hz | free-air resonance |
| Qts | 0.510 / 0.540 | dual 2 ohm / dual 4 ohm | |
| Vas | 17.37 / 17.89 | L | equivalent compliance |
| Sd | 339.7 | cm² | effective piston area |
| Xmax | 12.5 | mm | one-way linear travel |
| Pe | 500 | W | continuous RMS |
| SPL | 84.5 | dB | 1 W / 1 m, derived from T/S |
Driver parameters as published by NVX NSW10v3 owner’s manual. Curves computed against this enclosure’s actual net airspace.
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.
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