Proline X
Performance Optimized Down Fire Sealed 10" Enclosure | Prodigy NB3-10
SKU: PO 10-S DF NB3
- Alignment: 0.76 cu ft net, Qtc 0.526, Fc 47.1 Hz, F3 68.1 Hz - overdamped sealed tune for shallow-slope cabin coupling
- Driver: Prodigy NB3-10D4, 600W RMS, 11mm Xmax at 70% BL, 3.00" mounting depth
- Build: V-groove and dado joinery, double-layer 1.5" front baffle, perimeter cross-brace, side-mounted 12g OFC terminal cup
- Cabinet: 30"W x 15"D x 6.25"H measured in down fire position, square corners
Financing available — choose Shop Pay Installments at checkout.
Performance Optimized Down Fire Sealed 10" Enclosure | Prodigy NB3-10
The Performance Optimized Down Fire Sealed 10" Enclosure for the Prodigy NB3-10 is a low-profile sealed cabinet built around Prodigy Audio's shallow-mount 10" subwoofer. The NB3 Series exists to solve a depth problem, and this down fire cabinet extends that same logic to the enclosure itself: at 6.25 inches tall it slides into spaces that will not accept a conventional box.
The Prodigy NB3-10D4 is a 600-watt RMS dual 4-ohm subwoofer with 11mm of one-way Xmax at 70% BL in a 3.00 inch mounting depth. Motor design features a 70 ounce ferrite magnet, a 2.5" four-layer copper voice coil on a black aluminum former, and an FEA-designed center pole vent to pull heat out of the gap. Treated paper cone, rubber surround, stamped steel frame, Nomex and cotton blend spider with flat stitched tinsel leads.
The 0.76 cubic foot net volume was selected against the driver's published Thiele-Small data rather than a generic 10-inch rule of thumb. The NB3-10 has a small Vas of 14.43 liters against a 36.4 Hz Fs, which means sealed alignment is inherently a low-Qtc proposition on this driver no matter what volume you build. At 0.76 net the system lands at Qtc 0.526, Fc 47.1 Hz, and a predicted anechoic F3 of 68.1 Hz. That is deliberately on the overdamped side, and it is the correct choice here: shrinking the box to chase a textbook 0.707 alignment would require roughly 0.25 cubic feet net and would raise Fc by 17 Hz to buy back only 5 Hz of extension. The larger cabinet gives the shallower roll-off slope, the tighter impulse response, and the lowest Fc this driver can reach.
Anechoic F3 is not what you hear in a vehicle. In a down fire orientation coupling into a cabin floor, the gentle 12 dB per octave sealed slope meets rising cabin gain below 60 Hz, and in-car response typically extends well below the anechoic number.
Construction is the full Proline X Performance Optimized platform: ShopSabre CNC-cut Langboard Elite MDF with V-groove and dado joinery, perimeter cross-bracing, and a double-layer 1.5 inch front baffle (two 3/4 inch sheets bonded) for maximum baffle rigidity and driver isolation. Corners are square on Down Fire cabinets. The driver fires down into the floor with the terminal cup side mounted, keeping the connection accessible with the cabinet in place. Terminal cup is our Proline X ABS/carbon fiber composite pre-wired with 12 gauge OFC.
Bring your own Prodigy NB3-10D4. Mount cutout is direct-fit.
Manufactured in Tullahoma, Tennessee. 1-year enclosure warranty.
| Enclosure Type | Sealed | Down Fire Geometry | Floor-Coupled |
| Driver-Specific Fitment | Prodigy NB3-10D4 (DVC 4Ω) |
| Internal Volume (Gross) | 0.86 Cubic Feet |
| Internal Volume (Net After Displacement) | 0.76 Cubic Feet |
| Target System Qtc | 0.526 (Overdamped | Based on Published T/S) |
| Predicted Fc | 47.1 Hz |
| Predicted F3 (Anechoic) | 68.1 Hz |
| Driver Displacement | 0.10 Cubic Feet (Published by Prodigy) |
| Baffle Configuration | Down Firing - Driver Fires Toward Floor |
| Material | Langboard Elite 3/4" MDF |
| Front Baffle Construction | Double-Layer 1.5" MDF (Two 3/4" Sheets Bonded) |
| 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 | 6.25 Inches |
| Dimension Reference | All External Dimensions Measured In Down Fire Position |
| Mounting Hole Diameter | 9.125 Inches (Prodigy Spec) |
| Mounting Depth Required | 3.00 Inches (Prodigy Spec) |
| Mounting Hardware | 8/32 Threaded Inserts | Stainless Steel Machine Screws Included |
| Terminal Cup | Proline X ABS/Carbon Fiber Composite | Side Mounted | 12g OFC Pre-Wired |
| Damping | Polyfill Pre-Installed |
| Recommended Power | 450-600 Watts RMS (Prodigy Rated: 600W RMS Continuous) |
| Carpet Finish | Dark Gray Trunkliner (Standard) or Plush Black (+$10) |
| Bundle Options | Enclosure Only (Bring Your Own NB3-10D4) |
| Warranty | 1-Year Limited (Enclosure) |
| Manufactured | Tullahoma, Tennessee, USA |
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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