Proline X
Performance Optimized Down Fire Sealed Dual 10" Enclosure | Prodigy NB3-10
SKU: PO 10D-S DF NB3
- Alignment: 0.32 cu ft net per chamber. Qtc 0.657, Fc 58.7 Hz, F3 63.6 Hz per driver
- Same height as our single NB3 cabinet at 6.25" — two drivers, better damping, 4.5 Hz deeper
- Chambers: Two fully separate sealed chambers, 3/4" MDF full divider, one shared side-mounted terminal cup
- Drivers: Pair of Prodigy NB3-10D4 (DVC 4Ω), 600W RMS each / 1200W combined, 11mm Xmax, 3.00" mounting depth
- Cabinet: 30"W x 15"D x 6.25"H in down fire position, square corners
Financing available — choose Shop Pay Installments at checkout.
Performance Optimized Down Fire Sealed Dual 10" Enclosure | Prodigy NB3-10
Proline X Performance Optimized Down Fire Dual 10" Sealed
Cut and tuned for a pair of Prodigy NB3-10D4
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, with cabinet height as the variable. A few drivers need a wider or deeper platform. | Compact per driver footprint. 21.5 by 14.5 inches on the 10 inch. |
| Front baffle | Single, 3/4 inch. | Double, 1.5 inch, outer layer machined as a flush recess. | 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 airspace, the cutout and the cabinet height all come from the Prodigy NB3-10D4's own published numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.
Two Drivers, No Extra Height
This cabinet stands 6.25 inches tall, which is exactly the height of our single-driver NB3 enclosure. Same footprint, same height, twice the drivers, and a better alignment on top of it.
That is not a packaging trick. It comes from the driver. The NB3-10D4 has a Qts of 0.407 and a small 14.43 litre Vas, and drivers with those numbers run overdamped in generous enclosures. Splitting the cabinet into two smaller chambers moves each driver closer to the target alignment rather than further from it.
The single cabinet gives its driver 0.76 cubic feet and lands at Qtc 0.526 with F3 at 68.1 Hz. Each chamber here gives 0.32 cubic feet and lands at Qtc 0.657 with F3 at 63.6 Hz. Better damped, four and a half hertz deeper, double the cone area, double the power handling, identical cabinet height.
Built Around the Prodigy NB3-10D4
Nothing about this cabinet is generic. Both baffle positions are bored to the NB3's 9 3/16 inch cutout, and the whole design exists because the driver mounts in 3.00 inches.
That depth is the entire reason the NB3 exists. Prodigy built it for under and behind truck seats, and it carries a 70 ounce ferrite magnet with a 2.5 inch high-temp four-layer copper voice coil on a black aluminum former, rated to 500 degrees Fahrenheit. An FEA designed center pole vent pulls heat out of the coil gap. The spider is a cotton and Nomex blend with stitched flat tinsel leads, which is the detail that stops the ticking unstitched leads develop at high excursion over time.
11mm of one-way Xmax at 70% BL, 600 watts RMS each. Across the pair that is 1200 watts RMS combined.
True net, not marketing net. Internal volume is calculated from the machined cavity dimensions and Prodigy's published 0.10 cubic foot driver displacement, not estimated from external dimensions minus wall thickness.
Two Chambers, Not One
This enclosure follows the Proline X standing design rule for dual sealed builds: two fully separate chambers divided by a bonded full-height 3/4 inch MDF panel.
Two drivers sharing one sealed volume interact acoustically. Each driver's compression phase becomes the pressure environment the other is working against, which smears transient response and blurs the alignment each would have on its own. A full divider eliminates that entirely. Each NB3-10D4 gets its own 0.32 cubic feet and its own polyfill.
On this build the divider does double duty, because the smaller per-driver volume is the reason the alignment improves. Shared-chamber duals cannot do this.
Down Fire 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 both chambers airtight under sustained pressure cycling. Corners are square on Down Fire cabinets.
The cabinet measures 30 inches wide by 15 inches deep by 6.25 inches tall, measured in the down fire position. Feet ship with the enclosure but are not installed, so plan the space around where you intend to mount them.
Double Baffle, Flush Recess
Front baffles are 1.5 inches at both driver positions, two bonded 3/4 inch sheets, with the outer layer machined as a flush recess so each driver bolts to the inner layer.
One Shared Terminal Cup
Proline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, side mounted and pre-wired in 12 gauge OFC to both driver positions in parallel.
Separate Chambers
A bonded full-height 3/4 inch divider gives each driver its own sealed volume and its own polyfill, so neither driver works against the other.
What The Small Chambers Mean In Practice
At 0.32 cubic feet per driver the air spring is stiff, which is what raises the system resonance to 58.7 Hz and mechanically restricts excursion at the very bottom. That protects the driver, and it means low frequency output leans on cabin gain rather than on raw cone travel.
Firing down into the floor, the sealed rolloff meets rising cabin gain below 60 Hz and in-car response extends well below the anechoic figure. In a truck cab, which is where a 3 inch deep driver is meant to live, the result is tight and controlled rather than thin. With 11mm of Xmax and 600 watts per driver on tap, there is headroom behind it.
Prodigy publishes a sealed range of 0.75 to 1.0 cubic feet, so this sits well under their figure. Their number reads like a target for prefab truck enclosures where cabin gain does most of the work. Ours is the anechoic answer, and on a bench it measures better.
Power and Wiring
Prodigy rates the NB3-10D4 at 600 watts RMS continuous, 1200 watts peak. Across the pair that is 1200 watts RMS combined. Target 450 to 600 watts per driver.
Each driver is dual 4-ohm, so final impedance is set at the drivers rather than at the cup. Wire both identically, since mismatched wiring between chambers will split power unevenly, and confirm the resulting load against your amplifier's minimum stable impedance before powering the system.
Bring your own pair of Prodigy NB3-10D4 subwoofers. The enclosure carries a 1 year limited warranty.
Cut for the Driver, Not the Catalog
Two separate chambers, one shared cup, built one at a time in Tullahoma, Tennessee.
| Series | Proline X Performance Optimized Down Fire |
| Compatible Driver | Prodigy NB3-10D4 (DVC 4Ω), pair required. Direct fit, no other driver |
| Enclosure Type | Sealed, dual driver, down fire, floor coupled |
| Firing Direction | Down firing, both drivers fire toward the floor |
| Chamber Configuration | Two fully separate chambers, full divider, single shared side-mounted terminal cup |
| External Width | 30 in |
| External Depth | 15 in |
| External Height | 6.25 in. Same as our single NB3 cabinet |
| Dimension Reference | All external dimensions measured in down fire position |
| Total Internal Volume, Gross | 0.84 cu ft |
| Per-Chamber Net Volume | 0.32 cu ft after displacement |
| Total Net Volume | 0.64 cu ft |
| Prodigy Suggested Sealed Range | 0.75 to 1.0 cu ft (see FAQ on why this runs smaller) |
| Target Qtc Per Chamber | 0.657 |
| Predicted Fc Per Driver | 58.7 Hz |
| Predicted F3 Per Driver | 63.6 Hz anechoic |
| Comparison, Single NB3 Cabinet | 0.76 cu ft net, Qtc 0.526, F3 68.1 Hz, same 6.25 in height |
| Driver Fs | 36.406 Hz |
| Driver Qts | 0.407 |
| Driver Qes / Qms | 0.495 / 2.282 |
| Driver Vas | 14.43 L / 0.510 cu ft each |
| Driver Re | 6.5 ohm |
| Driver BL | 23.365 |
| Driver Mms | 151.63 g |
| Driver Xmax | 11mm one way at 70% BL |
| Driver Sensitivity | 86.9 dB |
| Driver Displacement | 0.10 cu ft each, published by Prodigy |
| Power Handling | 600 W RMS each, 1200 W RMS combined, 1200 W peak each |
| Recommended Power | 450 to 600 W RMS per driver |
| Voice Coil Configuration | Dual 4 ohm per driver, impedance set at the drivers |
| Driver Voice Coil | 2.5 in, 4 layer copper, black aluminum former, 500F rated |
| Driver Motor | 70 oz ferrite, FEA designed center pole vent |
| Driver Spider | Cotton and Nomex blend, stitched flat tinsel leads |
| Driver Cone | Treated paper with rubber surround |
| Mounting Depth | 3.00 in, Prodigy spec |
| Woofer Opening | 9 3/16 in direct fit, both positions |
| Driver Overall Diameter | 10 3/8 in, Prodigy spec |
| Standoffs | None required. Feet ship uninstalled |
| Material | Langboard Elite MDF |
| Construction | CNC cut, dado and V groove joinery, perimeter cross brace |
| Panel Thickness | 0.75 in |
| Front Baffle | 1.5 in double baffle at both positions, outer layer flush recess |
| Chamber Divider | 3/4 in MDF full bonded panel |
| Corner Profile | Square, Down Fire series standard |
| Driver Mounting | 8/32 threaded inserts, stainless machine screws included, 2 sets |
| Terminal Cup | Proline X ABS and carbon fiber composite, side mounted |
| Internal Wiring | 12 gauge OFC to both driver positions in parallel |
| Damping | Polyfill pre-installed per chamber |
| Carpet | Plush Black |
| Weight | 35 lb |
| Bundle Options | Enclosure only, bring your own pair of NB3-10D4 |
| Warranty | 1 Year Limited |
| Built In | Tullahoma, Tennessee |
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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