A dark gray Proline PO 10-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.
A black rectangular speaker enclosure with a circular opening, shown on a dark brown gradient background with white text reading 'PO 10-S DF NB2' and 'Performance Optimized Series.' The enclosure is labeled 30 inches wide by 15 inches tall, and the Proline/Prodigy branding is visible.
A black Proline Prodigy PO 10-S DF NB2 sealed down firing subwoofer enclosure shown on a dark brown gradient background with product specifications and branding text.
A dark gray woofers enclosure from Proline Performance Optimized Series, labeled PO 10-S DF NB2, with dimension markings of 15 inches by 6.25 inches on a dark brown gradient background.
A dark gray Proline PO 10-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.
A black rectangular speaker enclosure with a circular opening, shown on a dark brown gradient background with white text reading 'PO 10-S DF NB2' and 'Performance Optimized Series.' The enclosure is labeled 30 inches wide by 15 inches tall, and the Proline/Prodigy branding is visible.
A black Proline Prodigy PO 10-S DF NB2 sealed down firing subwoofer enclosure shown on a dark brown gradient background with product specifications and branding text.
A dark gray woofers enclosure from Proline Performance Optimized Series, labeled PO 10-S DF NB2, with dimension markings of 15 inches by 6.25 inches on a dark brown gradient background.

Proline X

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

SKU: PO 10-S DF NB2

QUICK SPECS
  • Alignment: 0.96 cu ft net, Qtc 0.640, Fc 42.7 Hz, F3 47.2 Hz, a well damped sealed alignment below the maximally flat reference
  • Driver: Prodigy NB2-10D4 (DVC 4Ω), 350W RMS / 700W peak, 14mm Xmax at 70% BL, 5.625" mounting depth
  • Build: Proline X V-groove and dado joinery, double-layer 1.5" front baffle with flush outer recess, milled magnet relief, 12g OFC side-mounted terminal cup
  • Cabinet: 30"W x 15"D x 7.25"H measured in down fire position, square corners
Shipping Icon
Shipping Included No freight charges at checkout. What you see is what you pay.
USA Flag Rounded
Built in Tennessee CNC cut from 3/4" Langboard Elite MDF. V-groove and dado joinery.
Gear icon
Advanced Terminal Cup Built in-house. ABS/Carbon Fiber. Stainless steel hardware. Copper ring terminals.
$ 259.99
In Stock and Ready to Ship
Shop Pay Financing available. Choose Shop Pay Installments at checkout.
A dark gray Proline PO 10-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.

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

Regular price $ 259.99
Sale price $ 259.99 Regular price
Unit price
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 0.96 cu ft
Weight 34.5 lbs
Front Panel Thickness 1.5"
INSTALLER'S TAKE

Qtc 0.640. That is the best-damped alignment in this entire program, across every driver family we have built for, and it happened by accident.

Here is the sequence. The NB2-10D4 mounts 5.625 inches deep. Our double baffle recovers 0.75 of that because the outer layer is a flush recess and the driver bolts to the inner layer. The milled magnet relief recovers another 0.375. Add half an inch of clearance behind the motor and the minimum internal height is 5 inches, which is 0.96 net on this footprint. Prodigy recommends 0.65. We cannot build 0.65 with this driver in the box.

Normally I would flag forced oversizing as a compromise. Not here. At 0.65 net this driver sits around Qtc 0.72. At 0.96 it drops to 0.640, which is tighter, lower group delay, shallower rolloff slope, and about a hertz deeper. The constraint made the box better.

On the driver: 14mm of Xmax and a double-stacked magnet at this price point are not normal. Most drivers in this bracket run a single magnet and 10 to 12mm. The detail I appreciate most is the tinsel leads stitched to the spider. Unstitched leads slap against the cone at high excursion and develop a ticking noise that gets worse over months. Prodigy solved it.

One thing worth knowing before you commit: at 5.625 inches this is not a shallow driver, and the cabinet is 7.25 inches tall as a result. If you need under-seat clearance, the NB3 shallow series in this same Down Fire line comes in at 6.25 inches. If you have the room, the NB2 is the better performer of the two.

Dual 4 ohm coils, so 2 ohms parallel or 8 ohms series at the driver. Target 250 to 350 watts RMS.

Product Details
Specifications
Performance Graphs
Materials
Product Details

Proline X Performance Optimized Down Fire 10" Sealed

Cut and tuned for the Prodigy NB2-10D4

V-Groove and DadoLangboard Elite MDF0.96 cu ft NetMilled Magnet Relief
0.96cu ft net
0.685system Qtc
47.2 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 the NB2-10D4

Nothing about this cabinet is generic. The baffle is 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 into the panel opposite the baffle so the motor clears with half an inch to spare.

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

Published Thiele-Small figures: Fs 34.295 Hz, Qts 0.514, Qes 0.611, Qms 3.24, Vas 21.054 liters, Mms 165.223 g, BL 20.11 T/m, Re 6.1 ohms, sensitivity 84.2 dB at 1W/1m. Overall frame diameter is 10.375 inches.

Net Volume, Not Gross

We build this cabinet at 0.96 cubic feet net from 1.07 gross, after panel thickness, bracing and the driver's published 0.11 cubic feet of displacement are accounted for. Prodigy recommends 0.65 cubic feet sealed for this driver.

The difference is a fitment consequence, not a preference. The double baffle recovers 3/4 inch because the outer layer is a flush recess and the driver bolts to the inner layer, the milled relief recovers another 3/8 inch, and half an inch of clearance stays behind the motor vent. Even after all of that the minimum internal height lands at 5 inches, which works out to 0.96 net on a 30 by 15 inch footprint. A 0.65 cubic foot cabinet cannot physically contain this driver.

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.

The oversizing lands in your favor. At Prodigy's 0.65 figure this driver sits near Qtc 0.72. At 0.96 it lands at Qtc 0.640, Fc 42.7 Hz, and a predicted F3 of 47.2 Hz. That is the lowest Qtc of any enclosure in the Proline X Down Fire line: below the maximally flat reference, with a gentler rolloff slope, lower group delay and tighter transient control. Firing down into the floor, that rolloff meets rising cabin gain below 60 Hz, so in-car response extends well below the anechoic figure.

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 the cabinet airtight under sustained pressure cycling. Perimeter cross-bracing and pre-installed polyfill 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

The front baffle is 1.5 inches, two bonded 3/4 inch sheets, with the outer layer machined as a flush recess so the driver bolts to the inner layer. That recovers 3/4 inch of internal clearance.

Side-Mounted Terminal Cup

Proline X ABS and carbon fiber composite cup with stainless hardware and copper ring terminals, pre-wired in 12 gauge OFC. Side mounted so it stays accessible with the baffle facing the floor.

Milled Magnet Relief

A 3/8 inch deep relief is milled into the panel opposite the baffle, directly behind the motor, with a half inch minimum kept clear behind the magnet vent. That is what lets a 5.625 inch driver live in a 7.25 inch cabinet.

Power and Warranty

Prodigy rates the NB2-10D4 at 350 watts RMS and 700 watts peak. Set gains for 250 to 350 watts RMS. The coils are dual 4-ohm, so final impedance is set at the driver: 2 ohms with the coils in parallel, 8 ohms in series. Confirm your amplifier is stable at the load you choose before powering the system.

Mounting hardware is 8/32 threaded inserts with stainless steel machine screws, included. The enclosure carries a 1 year limited warranty. Bring your own Prodigy NB2-10D4; the driver is 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
SeriesProline X Performance Optimized Down Fire
Driver-Specific FitmentProdigy NB2-10D4 (DVC 4Ω)
Enclosure TypeSealed | Down Fire Geometry | Floor-Coupled
Baffle ConfigurationDown Firing - Driver Fires Toward Floor
External Width30 Inches
External Depth15 Inches
External Height7.25 Inches
Dimension ReferenceAll External Dimensions Measured In Down Fire Position
Internal Volume (Gross)1.07 Cubic Feet
Internal Volume (Net After Displacement)0.96 Cubic Feet
Prodigy Recommended Sealed Volume0.65 Cubic Feet (See FAQ On Why This Cabinet Is Larger)
Target System Qtc0.640 (Well Damped | Lowest In The Down Fire Line)
Predicted Fc42.7 Hz
Predicted F347.2 Hz
Driver Fs34.295 Hz
Driver Qts0.514
Driver Qes / Qms0.611 / 3.24
Driver Vas21.054 Liters / 0.744 Cubic Feet
Driver Mms165.223 g
Driver Cms139.032 µm/N
Driver BL20.11 T/m
Driver Re6.1 Ohm
Driver Xmax14mm (One-Way at 70% BL)
Driver Displacement0.11 Cubic Feet (Published by Prodigy)
Driver Sensitivity84.2 dB (1W/1m)
Driver Power Handling350 Watts RMS / 700 Watts Peak
Driver Voice Coil2.0 in | 4-Layer Copper | Black Aluminum Former
Driver MotorDouble-Stacked Magnet | Center Pole Vent + Radial Backplate Holes
Driver Overall Diameter10.375 Inches (Prodigy Spec)
Mounting Depth Required5.625 Inches (Prodigy Spec)
Cutout Diameter9.250 Inches (Prodigy Spec)
Motor Clearance0.5 Inch Minimum Behind Magnet Vent
Magnet Relief3/8" Deep Milled Relief In Opposite Panel For Motor Clearance
MaterialLangboard Elite 3/4" MDF
ConstructionShopSabre CNC / Perimeter Cross-Brace
JoineryV-Groove and Dado (CNC-Cut)
Front Baffle ConstructionDouble-Layer 1.5" MDF | Outer Layer Flush Recess, Driver Mounts To Inner Layer
Corner ProfileSquare (Down Fire Series Standard)
Mounting Hardware8/32 Threaded Inserts | Stainless Steel Machine Screws Included
Voice Coil ConfigurationDual 4-Ohm | 2Ω Parallel or 8Ω Series At The Driver
Terminal CupProline X ABS/Carbon Fiber Composite | Side Mounted | 12g OFC Pre-Wired
DampingPolyfill Pre-Installed
Recommended Power250-350 Watts RMS (Prodigy Rated: 350W RMS)
Carpet FinishPlush Black
Bundle OptionsEnclosure Only (Bring Your Own Prodigy NB2-10D4)
Warranty1-Year Limited (Enclosure)
ManufacturedTullahoma, Tennessee, USA
Performance Graphs
Net airspace
0.96
cu ft per chamber
System Qtc
0.68
sealed
Half power
47.2
Hz · F3
Xmax at
316
W RMS · no filter
With 25 Hz subsonic
442
W RMS · +40%
Amplifier
350
W RMS recommended
This enclosure holds 0.96 cu ft net per chamber. In it the Prodigy Audio NB2-10 runs a system Qtc of 0.68 with half power at 47.2 Hz, and the cone reaches its 14.0 mm travel limit at 316 W, below the driver’s 350 W thermal rating, so travel is what stops you here, not heat. Run a subsonic filter at 25 Hz and that becomes 442 W — +126 W, or 40 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
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 D4 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

0.96 cu ft against a 21.1 L Vas.

α = Vas ÷ Vb = 0.77  ·  Fc = Fs√(α+1) = 46 Hz  ·  Qtc = 0.68
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
D4 · Qtc 0.68, Fc 46 Hz, F3 47.2 Hz
The box lifts resonance from 34.3 Hz free-air to 46 Hz and half power lands at 47.2 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.

PXmax = 316 W unfiltered  →  442 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 4 8 12 16 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 14.0 mm 316 W reaches Xmax here
D4 · 316 W, no filterD4 · 442 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 316 W, reached first at 20 Hz. It sits under the 350 W the driver can take thermally, so the enclosure sets the ceiling, not the voice coil. 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 442 W before hitting the same 14.0 mm. That is 40 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs34.30Hzfree-air resonance
Qts0.514D4
Vas21.05Lequivalent compliance
Sd328.4cm²effective piston area
Xmax14mmone-way linear travel
Pe350Wcontinuous RMS
SPL83.3dB1 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

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

Handcrafted in USA

Hand-assembled at our facility in Tullahoma, TN. Every enclosure is inspected before it ships.

Tuned to the Build

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.

Frequently Asked Questions

Why is this enclosure larger than Prodigy's recommended 0.65 cubic feet?

What does a Qtc of 0.640 actually mean?

How does the NB2 compare to the NB3 shallow series?

How do I wire this enclosure and set my impedance?

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

Why are the corners square instead of radiused?

How is this enclosure built?

Is the Prodigy NB2-10 subwoofer included with this enclosure?

Related Articles