A Proline Performance Optimized Series PO 10D-S DF NB2 woofer subwoofer enclosure, shown as a black foam-lined metal box with two circular driver openings containing white foam. The image features product specifications on the left and a dark brown gradient background.

A black rectangular speaker mounting plate with two circular cutouts showing white marbled speaker cones, labeled as a Proline Performance Optimized Series PO 10D-S DF NB2 product graphic with dimensions 30 inches by 15 inches and feature text on a dark brown gradient background.

A promotional product graphic for a Proline PO 10D-S DF NB2 woofers, showing a single black rectangular woofer with dimension callouts of 7.25 inches wide and 15 inches tall, plus text describing sealed down firing design and optimized series features.

A dark gray Proline PO 10D-S DF NB2 speaker cabinet shown on a dark brown gradient background with technical specifications and dimensions printed around it, including 30 inches width, 7.25 inches height, and feet adding 1.

Proline X

Performance Optimized Down Fire Sealed Dual 10" Enclosure | Prodigy NB2-10

Q: Why is the dual the same height as the single-driver enclosure?

Because cabinet height on this driver is set by mounting depth, not by volume. The NB2-10D4 mounts 5.625 inches deep, which requires a minimum internal height of 5 inches once you account for the flush-recess baffle, the milled magnet relief, and half an inch of clearance behind the motor.That requirement is vertical, and the chamber divider runs vertically too, so splitting the cabinet into two chambers does not change it at all. Both the single and dual versions stand 7.25 inches tall on the same 30 by 15 inch footprint. The dual gives you a second driver and double the cone area for no additional height.

Q: Why is the dual's alignment better than the single's?

Because halving the chamber width brings the per-driver volume closer to Prodigy's target. The single-driver cabinet is forced to 0.96 cubic feet net by driver clearance, well above Prodigy's 0.65 recommendation. Splitting the same cabinet into two chambers gives each driver 0.52 cubic feet, much nearer their figure.The result is Qtc 0.700 per driver, essentially the textbook maximally flat alignment of 0.707. The single lands at 0.640, which is also excellent but more damped. Both are good; the dual is simply closer to the reference target while adding 6 dB of output.

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

Because two drivers in a shared sealed volume interact acoustically. Each driver's compression phase becomes the pressure environment the other driver is working against, which smears transient response and blurs the alignment each would have on its own. A full-height bonded 3/4 inch MDF divider eliminates that completely. Each NB2-10D4 gets its own 0.52 cubic feet net plus its own polyfill. Separate chambers are the standing design rule on every Proline X dual sealed enclosure.

Q: How is this enclosure wired, and how do I set my final impedance?

The enclosure uses one side-mounted Proline X terminal cup with a single pair of posts, pre-wired in 12 gauge OFC to both driver positions in parallel. You do not wire the two chambers separately at the amplifier.Final impedance is set at the drivers. Each NB2-10D4 has dual 4-ohm voice coils, so you choose how to wire the two coils on each driver and that determines the load the amplifier sees through the cup. Wire both drivers identically, since mismatched wiring between chambers will split power unevenly. Confirm the resulting load against your amplifier's minimum stable impedance before powering the system.

Q: Where is the terminal cup located on a down fire enclosure?

Side mounted, and there is one cup serving both chambers rather than one per chamber. Every Proline X Performance Optimized enclosure uses a side mounted terminal cup regardless of alignment, whether standard, wedge, or down fire. On this cabinet that keeps the connection fully accessible with the enclosure in its installed position, since both baffles face the floor. The cup is our Proline X ABS and carbon fiber composite unit, recessed, with stainless hardware, copper ring terminals, and pre-wired 12 gauge OFC.

Q: Why are the corners square instead of radiused?

Down Fire cabinets are built with square corners as a series standard. The 3 inch top down corner radius used on other Proline X alignments does not apply here. A down fire box is a low, wide platform that sits flat against a floor or cargo deck, and square corners maximize usable internal volume for a given footprint while keeping the cabinet stable on its mounting surface.

Q: How is this enclosure built?

V-groove and dado joinery, CNC-cut on ShopSabre routers from Langboard Elite MDF. Every panel joint is a machined interlocking groove that mechanically locks the panels before adhesive is applied, which keeps both chambers airtight under sustained pressure cycling. The chamber divider is a full-height bonded 3/4 inch panel.Front baffles are double-layer at 1.5 inches at both driver positions, with the outer layer machined as a flush recess so each driver bolts to the inner layer. A 3/8 inch relief is milled behind each motor. Perimeter cross-bracing and pre-installed polyfill in each chamber complete the build. Assembled and inspected in Tullahoma, Tennessee.

Q: Are the Prodigy NB2-10 subwoofers included with this enclosure?

No. This listing is for the enclosure only. Bring your own pair of Prodigy NB2-10D4 subwoofers. The cutouts, mounting depth and magnet clearance are cut specifically for this driver at both positions.

SKU: PO 10D-S DF NB2

QUICK SPECS

Alignment: 0.52 cu ft net per chamber, Qtc 0.801, above the maximally flat reference. Fc 46.7 Hz, F3 47.9 Hz per driver
Chambers: Two fully separate sealed chambers, 3/4" MDF full divider, one shared side-mounted terminal cup
Drivers: Pair of Prodigy NB2-10D4 (DVC 4Ω), 350W RMS each / 700W combined, 14mm Xmax
Cabinet: 30"W x 15"D x 7.25"H, the same height as the single-driver cabinet

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.

$ 299.99

In Stock and Ready to Ship

Financing available. Choose Shop Pay Installments at checkout.

Complete Your System

Prodigy Audio 1200 Watt Mono Block Amplifier NBM1200.1 - Prodigy Amplifier for car audio systems

Prodigy Audio Prodigy Audio 1200 Watt Mono Block Amplifier | NBM1200.1 $ 272.99

Performance Optimized Down Fire Sealed Dual 10" Enclosure | Prodigy NB2-10

$ 299.99

Enclosure Type Sealed

External Dimensions 30" W x 15" D x 7.25" H (measured in down fire position)

Gross Volume 1.11 cu ft

Net Volume 1.04 total / 0.52 per chamber cu ft

Weight 33 lbs

Front Panel Thickness 1.5"

INSTALLER'S TAKE

This is the best value proposition in the Down Fire program, and the reason is geometry rather than pricing.

The NB2-10D4 mounts 5.625 inches deep, which forces a minimum internal height of 5 inches on any cabinet built around it. That requirement does not change when you split the box into two chambers, because the divider runs vertically and the driver depth is a vertical measurement. So this dual comes out at exactly 7.25 inches, the same height as the single-driver cabinet. Second driver, double the cone area, no additional height.

And the alignment gets better, not worse. Halving the chamber width brings each driver down to 0.52 net, which lands at Qtc 0.801. Textbook maximally flat is 0.707. This is within seven thousandths of the number box design books tell you to aim for, and closer to Prodigy's own 0.65 recommendation than the single cabinet manages.

Separate chambers, as on every dual sealed build we do. Two drivers sharing one volume interact acoustically, each one's compression stroke becoming the pressure environment the other works against, which smears transients. A full-height bonded divider stops it.

700 watts RMS combined across the pair, 14mm of Xmax each, double-stacked magnets, and tinsel leads stitched to the spider so they will not develop the ticking that unstitched leads get at high excursion. For the money there is not a better dual 10 build in this line.

One side-mounted cup feeds both driver positions in parallel. Each driver is dual 4 ohm, so set impedance at the drivers and wire both identically. Target 250 to 350 watts RMS per driver.

Product Details

Proline X Performance Optimized Down Fire Dual 10" Sealed

Cut and tuned for a pair of Prodigy NB2-10D4

V-Groove and DadoLangboard Elite MDF1.04 cu ft NetSeparate Chambers

1.04cu ft net total

0.801system Qtc per driver

47.9 HzF3 rolloff

7.25 incabinet height

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 NB2-10D4's own published numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.

Built Around a Pair of NB2-10D4

Nothing about this cabinet is generic. Both baffles are bored to the NB2-10D4's 9.250 inch cutout, the internal height is set by its 5.625 inch mounting depth, and a 3/8 inch relief is milled behind each motor.

Each driver is a dual 4-ohm ten rated 350 watts RMS and 700 watts peak, with 14mm of one-way Xmax at 70% BL. Across the pair that is 700 watts RMS combined and double the cone area. A 2.0 inch four-layer copper voice coil rides a black aluminum former inside a double-stacked magnet motor, with a center pole vent plus radial backplate holes for cooling. The tinsel leads are stitched to the spider, which is the detail that prevents the ticking unstitched leads develop at high excursion.

Published Thiele-Small figures per driver: Fs 34.295 Hz, Qts 0.514, Vas 21.054 liters, displacement 0.11 cubic feet.

Net Volume, Not Gross

This is a two chamber cabinet. Each driver gets 0.52 cubic feet net, for 1.04 cubic feet net total, taken from 1.26 gross after panel thickness, the divider, bracing and each driver's published 0.11 cubic feet of displacement are accounted for. Every alignment figure on this page is per chamber, because acoustically each driver only ever sees its own 0.52.

True net, not marketing net. Internal volume is calculated from the machined cavity dimensions and the driver's published displacement, not estimated from external dimensions minus wall thickness.

Per chamber the result is Qtc 0.801 with Fc at 46.7 Hz and a predicted F3 of 47.9 Hz. That sits above the 0.707 maximally flat reference, which trades a little damping for a slightly firmer corner. It is also closer to Prodigy's own 0.65 cubic foot sealed recommendation than the single driver cabinet manages, since halving the chamber width brings the volume back down toward their target rather than away from it. Firing down into the floor, the sealed rolloff meets rising cabin gain below 60 Hz, so in-car response extends well below the anechoic figure.

Here is the part worth knowing. The 5.625 inch mounting depth forces a minimum internal height of 5 inches no matter how the cabinet is divided, because depth is a vertical measurement and the divider runs vertically too. So this dual stands at 7.25 inches, exactly the same as the single driver cabinet, on the same 30 by 15 inch footprint. A second driver for no additional cabinet height at all.

Down Fire Construction

Cut with V-groove and dado joinery on our ShopSabre routers from Langboard Elite 3/4 inch MDF. Every panel joint is a machined interlocking groove that mechanically locks before adhesive is applied, which keeps both chambers airtight under sustained pressure cycling. Perimeter cross-bracing and polyfill pre-installed in each chamber complete the build. Corners are square on Down Fire cabinets. External dimensions are 30 inches wide by 15 inches deep by 7.25 inches high, measured in the down fire position.

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. That recovers 3/4 inch of internal clearance.

Side-Mounted Terminal Cup

One Proline X ABS and carbon fiber composite cup serves both chambers, with stainless hardware and copper ring terminals, pre-wired in 12 gauge OFC to both driver positions in parallel. Side mounted so it stays accessible with the baffles facing the floor.

Separate Chambers

A full height bonded 3/4 inch MDF divider gives each driver its own sealed volume. Two drivers sharing one chamber interact acoustically, each one's compression stroke becoming the pressure the other works against, which smears transients. The divider removes that completely.

Power and Warranty

Prodigy rates each NB2-10D4 at 350 watts RMS and 700 watts peak, so 700 watts RMS combined across the pair. Set gains for 250 to 350 watts RMS per driver. Each driver has dual 4-ohm coils and the final load is set at the drivers, then seen by the amplifier through the shared cup. Wire both drivers identically, since mismatched wiring between chambers splits power unevenly, and confirm the resulting load against your amplifier's minimum stable impedance before powering the system.

Mounting hardware is 8/32 threaded inserts with stainless steel machine screws, two sets included. The enclosure carries a 1 year limited warranty. Bring your own pair of Prodigy NB2-10D4; the drivers are purchased separately.

Cut for the Driver, Not the Catalog

Every Proline X Performance Optimized cabinet is machined to one driver's published cutout, mounting depth and displacement, then built one at a time in Tullahoma, Tennessee.

Specifications

Series	Proline X Performance Optimized Down Fire
Enclosure Type	Sealed \| Dual Driver \| Down Fire Geometry \| Floor-Coupled
Chamber Configuration	Two Fully Separate Chambers \| Full Divider \| Single Shared Side-Mounted Terminal Cup
Driver-Specific Fitment	Prodigy NB2-10D4 (DVC 4Ω) \| Pair Required
Total Internal Gross Volume	1.26 Cubic Feet
Per-Chamber Net Volume	0.52 Cubic Feet
Total Net Volume	1.04 Cubic Feet
Target Qtc Per Chamber	0.700 (Computed from Published T/S)
Predicted Fc Per Driver	46.7 Hz
Predicted F3 Per Driver	40.9 Hz
Driver Fs	34.295 Hz
Driver Qts	0.514
Driver Vas	21.054 Liters Each
Driver Xmax	14mm (One-Way at 70% BL)
Driver Displacement	0.11 Cubic Feet Each (Published by Prodigy)
Power Handling	350 Watts RMS Each / 700 Watts RMS Combined
Driver Voice Coil	2.0 in \| 4-Layer Copper \| Black Aluminum Former
Driver Motor	Double-Stacked Magnet \| Center Pole Vent + Radial Backplate Holes
Mounting Depth Required	5.625 Inches (Prodigy Spec)
Cutout Diameter (Each)	9.250 Inches (Prodigy Spec)
Baffle Configuration	Down Firing - Both Drivers Fire Toward Floor
Material	Langboard Elite 3/4" MDF
Front Baffle Construction	Double-Layer 1.5" MDF at Both Driver Positions \| Outer Layer Flush Recess
Magnet Relief	3/8" Deep Milled Relief Behind Each Motor
Chamber Divider	3/4" MDF Full Bonded Panel
Joinery	V-Groove and Dado (CNC-Cut)
Corner Profile	Square (Down Fire Series Standard)
Construction	ShopSabre CNC / Perimeter Cross-Brace
External Width	30 Inches
External Depth	15 Inches
External Height	7.25 Inches - Same As The Single-Driver Cabinet
Dimension Reference	All External Dimensions Measured In Down Fire Position
Voice Coil Configuration	Dual 4-Ohm Per Driver - Final Impedance Set At The Drivers
Mounting Hardware	8/32 Threaded Inserts \| Stainless Steel Machine Screws Included \| 2 Sets
Terminal Cup	One Proline X ABS/Carbon Fiber Composite \| Side Mounted \| 12g OFC Pre-Wired to Both Driver Positions
Damping	Polyfill Pre-Installed Per Chamber
Recommended Power Per Driver	250-350 Watts RMS (Prodigy Rated: 350W RMS)
Carpet Finish	Plush Black
Bundle Options	Enclosure Only (Bring Your Own Pair of Prodigy NB2-10D4)
Warranty	1-Year Limited (Enclosure)
Manufactured	Tullahoma, Tennessee, USA

Performance Graphs

Net airspace

0.52

cu ft per chamber

System Qtc

0.80

sealed

Half power

47.9

Hz · F3

Xmax at

530

W RMS · no filter

With 25 Hz subsonic

591

W RMS · +11%

Amplifier

350

W RMS recommended

This enclosure holds 0.52 cu ft net per chamber. In it the Prodigy Audio NB2-10 runs a system Qtc of 0.80 with half power at 47.9 Hz, and the cone reaches its 14.0 mm travel limit at 530 W, above the driver’s 350 W thermal rating, so heat stops you before travel does. Run a subsonic filter at 25 Hz and that becomes 591 W — +60 W, or 11 percent more power for the same 14.0 mm of travel.

01Is it a sealed driver?

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

EBP = Fs ÷ Qes = 56.1

D4 · EBP 56.1

At 56.1 the NB2-10 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

0.52 cu ft against a 21.1 L Vas.

α = Vas ÷ Vb = 1.43 · Fc = Fs√(α+1) = 53 Hz · Qtc = 0.80

D4 · Qtc 0.80, Fc 53 Hz, F3 47.9 Hz

The box lifts resonance from 34.3 Hz free-air to 53 Hz and half power lands at 47.9 Hz, anechoic, before any cabin gain.

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

P_Xmax = 530 W unfiltered → 591 W with a 25 Hz subsonic

D4 · 530 W, no filterD4 · 591 W with subsonic at 25 Hz, 24 dB/octXmax 14.0 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 14.0 mm. Unfiltered that is 530 W, reached first at 25 Hz. It sits above the 350 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 591 W before hitting the same 14.0 mm. That is 11 percent more amplifier for the price of one filter setting.

Param	Value	Unit	Note
Fs	34.30	Hz	free-air resonance
Qts	0.514		D4
Vas	21.05	L	equivalent compliance
Sd	328.4	cm²	effective piston area
Xmax	14	mm	one-way linear travel
Pe	350	W	continuous RMS
SPL	83.3	dB	1 W / 1 m, derived from T/S

Driver parameters as published by prodigyaudio.com product page; Sd derived from Vas and Cms. 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.