Proline X
Performance Optimized Down Fire Wide Sealed Dual 10" Enclosure | Audiofrog GB10
SKU: PO 10D-S DFW GB10
- Best For: Dual Audiofrog GB10 under a rear seat or on a narrow cargo floor
- Net Volume: 0.606 cu ft per chamber, 1.212 cu ft total, Audiofrog's own 17 L recommendation
- Alignment: Qtc 0.846, Fc 51.4 Hz, F3 44.3 Hz (GB10D2); Qtc 0.820, Fc 52.5 Hz, F3 46.2 Hz (GB10D4)
- Down Fire Wide: 41"W x 12"D x 8.5"H, 3 in shallower than the standard 30 x 15
- Impedance: Switch selected; set both drivers HIGH: 2 ohms on a D2 pair, 4 ohms on a D4 pair
- Construction: Dual Chamber | V-Groove/Dado | Double 1.5" Baffle | Threaded Inserts | Feet Included
Financing available. Choose Shop Pay Installments at checkout.
Performance Optimized Down Fire Wide Sealed Dual 10" Enclosure | Audiofrog GB10
More enclosures cut for Audiofrog subwoofers: Audiofrog Subwoofer Boxes
Proline X Performance Optimized Down Fire Wide Dual 10" Sealed
Under rear seat fitment for trucks and SUVs. Cut for a pair of Audiofrog GB10
The Down Fire Wide Format
Down Fire Wide is the Performance Optimized answer to a specific problem: the space under the rear seat of a truck or SUV, or a narrow cargo floor, is long and shallow, and the standard 30 by 15 inch Down Fire cabinet will not go in it.
This cabinet takes the same pair of Audiofrog GB10 and turns the footprint sideways. It runs 41 inches wide by 12 inches deep by 8.5 inches tall: 3 inches shallower front to back than the standard 30 x 15 cabinet and 11 inches longer. The airspace given up in depth is recovered along the length, and each driver still gets its own separate chamber.
Which one to choose. If you have 15 inches of depth, the standard 30 x 15 Audiofrog GB10 enclosure is the pick. Choose Down Fire Wide when depth is the limit: under a rear bench or on a narrow cargo floor, with at least 12 inches of depth and 41 inches of run.
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 cutouts, the cabinet height and the airspace all come from the Audiofrog GB10's own published numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.
Built Around the Audiofrog GB10
Both baffle positions are bored to the GB10's 9.2520 inch cutout, and the cabinet height clears its 6.260 inch mounting depth with 1.49 inches above the motor. The 10.709 inch frame sits on the 12 inch deep baffle.
Audiofrog's GB10 is a 76 mm coil on a vented cast aluminum basket with a copper pole cap, in two switchable coil versions, the GB10D2 and GB10D4. They share a frame, cutout and mounting depth, so the cabinet fits either. Excursion is 17.6 mm one way on the D2 and 19 mm on the D4, and each driver is rated 500 watts RMS.
Audiofrog publishes Thiele-Small parameters per coil version rather than one shared set, because they measure each one, so the alignment on this page is carried per coil rather than averaged.
Net Volume and Alignment
Each chamber holds 0.606 cubic feet net, 1.212 cubic feet across both chambers, from 0.731 gross per chamber after the driver's 0.111 cubic feet of displacement.
Computed from Audiofrog's published Thiele-Small parameters for each coil version, per coil version and per chamber: GB10D2: Qtc 0.846, Fc 51.4 Hz, F3 44.3 Hz. GB10D4: Qtc 0.820, Fc 52.5 Hz, F3 46.2 Hz.
Height is the free dimension. With the footprint fixed at 41 by 12, the cabinet height was solved to put each chamber on the 0.60 cubic feet the standard 30 x 15 cabinet was built to, then rounded up to the next sixteenth so the airspace lands on the target rather than under it. The 6.26 inch mounting depth leaves 1.49 inches above the motor, so airspace set the height here, not clearance.
That airspace is Audiofrog's own recommended sealed volume, 17 liters in their documentation, and theirs is a net figure exactly as ours is. It gives a moderately damped alignment rather than a textbook 0.707, which is the voicing Audiofrog built the recommendation around.
These are anechoic figures. Firing down into the floor, the sealed rolloff meets rising cabin gain, so in-car response extends below them.
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. Each driver gets its own 0.606 cubic feet and its own polyfill.
On a long cabinet the divider does structural work as well, tying the front and rear walls together at the center of a 41 inch span.
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 both chambers airtight under sustained pressure cycling. Corners are square on Down Fire cabinets, no radii. Polyfill is installed as a light wall lining, finished in plush black carpet.
The cabinet measures 41 inches wide by 12 inches deep by 8.5 inches tall, measured in the down fire position, excluding feet. The 1.75 inch feet ship with the enclosure but are not installed. Fitted, the installed height is 10.25 inches, so plan the space around where you intend to mount them.
1.5 Inch Double Baffle
Two 3/4 inch layers laminated to 1.5 inches, the outer layer machined as a flush recess so each driver bolts to the inner layer. 8/32 threaded inserts with stainless machine screws at every mounting location.
Frame on a 12 Inch Baffle
The GB10's 10.709 inch frame sits on the 12 inch deep baffle at both positions, bored to the 9.2520 inch cutout. At the 1.75 inch foot height the floor slot around each cone is 0.95 of the cone area.
Separate Chambers
A bonded full-height 3/4 inch divider gives each driver its own 0.606 cubic feet and its own polyfill, and ties the walls together mid span.
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.
Power and Wiring
The GB series does not bring its coils out to the terminals. Each driver carries an impedance selection switch, and the terminal cup wires the two positions in parallel, so the switch alone decides what the amplifier sees. Set both drivers to the HIGH position. A pair of D2 drivers at 4 ohms each presents 2 ohms; a pair of D4 drivers at 8 ohms each presents 4 ohms. Leaving both in the low position halves that again, to 0.5 ohms on a D2 pair, which almost no amplifier is stable into.
Set both switches the same way, and set them before you mount the drivers, because the switch faces the motor. Power handling is 1000 watts RMS total across the pair; aim for roughly 700 to 1000 watts at the impedance you select.
Bring your own pair of Audiofrog GB10, D2 or D4, two of the same version. The enclosure carries a 1 year limited warranty. Questions on fitment or amplifier matching, call 931-563-5151.
Cut for the Driver, Not the Catalog
Down Fire Wide, built for the space under a rear bench. We build every one to order in Tullahoma, Tennessee.
| Specification | Value |
|---|---|
| Series | Proline X Performance Optimized Down Fire Wide |
| Compatible Driver | Audiofrog GB10, GB10D2 or GB10D4, quantity 2. Direct fit |
| Enclosure Type | Sealed, dual driver, down fire, floor coupled |
| Intended Fitment | Under the rear seat of trucks and SUVs, or narrow cargo floors, where depth is the limiting dimension |
| Chamber Configuration | Two fully separate chambers, full divider, one shared side-mounted terminal cup |
| External Width | 41 in |
| External Depth | 12 in |
| External Height | 8.5 in, measured in down fire position, excludes feet |
| Installed Height | 10.25 in with the 1.75 in feet fitted |
| Internal Volume, Gross | 1.462 cu ft total, 0.731 per chamber |
| Internal Volume, Net Acoustic | 0.606 cu ft per chamber, 1.212 cu ft total, after displacement |
| Alignment per chamber, GB10D2 | Qtc 0.846, Fc 51.4 Hz, F3 44.3 Hz anechoic |
| Alignment per chamber, GB10D4 | Qtc 0.820, Fc 52.5 Hz, F3 46.2 Hz anechoic |
| Height Set By | Airspace; 1.49 in clear above the motor |
| Comparison, Standard Down Fire | 30 x 15 x 9.06 in, 0.60 cu ft net per chamber |
| Driver Cutout | 9.2520 in, both positions |
| Driver Mounting Depth | 6.260 in required |
| Frame Outer Diameter | 10.709 in |
| Floor Slot Ratio | 0.95 at the 1.75 in foot height |
| Audiofrog Recommended Sealed Volume | 17 L net per driver |
| Driver Fs / Qts / Vas, D2 | 31.0 Hz / 0.51 / 30.0 L |
| Driver Fs / Qts / Vas, D4 | 32.0 Hz / 0.50 / 29.0 L |
| Driver Sd | 346.3 cm² each |
| Power Handling | 500 W RMS each, 1000 W RMS total across the pair |
| Impedance | Switch selected on the driver. D2 selects 1 or 4 ohms, D4 selects 2 or 8. Set both HIGH |
| Xmax | 17.6 mm one way on the D2, 19 mm on the D4 |
| Driver Displacement | 0.111 cu ft each, published by Audiofrog |
| Material | Langboard Elite 3/4 in MDF |
| Construction | ShopSabre CNC cut, V-groove and dado joinery, full-height bonded divider |
| Front Baffle | 1.5 in double baffle at both positions, outer layer machined as a flush recess |
| Corner Profile | Square, Down Fire series standard |
| Driver Mounting | 8/32 threaded inserts, stainless machine screws included, 2 sets |
| Terminal Cup | One Proline X ABS and carbon fiber composite, side mounted, shared by both chambers |
| Internal Wiring | 12 gauge OFC, parallel to both driver positions |
| Damping | Polyfill installed, light wall lining in each chamber |
| Feet | 1.75 in, included, shipped uninstalled |
| Carpet | Plush black |
| 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
0.606 cu ft against a 30.0 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 17.6 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 31.00 / 32.00 | Hz | free-air resonance |
| Qts | 0.510 / 0.500 | D2 / D4 | |
| Vas | 30.00 / 29.00 | L | equivalent compliance |
| Sd | 346.3 | cm² | effective piston area |
| Xmax | 17.6 | mm | one-way linear travel, D2 coil. The D4 coil is rated 19 mm on the same cone; the smaller figure is plotted so the power shown is conservative for both. |
| Pe | 500 | W | continuous RMS |
| SPL | 84.0 | dB | 1 W / 1 m, derived from T/S |
Driver parameters as published by audiofrog.com and the GB Series Subwoofer 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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