Proline X
Performance Optimized Down Fire Sealed Dual 10" Enclosure | Kicker CompRT
SKU: PO 10D-S DF CompRT
- Alignment: 0.793 cu ft net per chamber, 1.586 cu ft net total. Qtc 0.924, Fc 48.3 Hz, F3 39.5 Hz, matching the single-driver Down Fire cabinet
- Chambers: Two fully separate sealed chambers, 3/4 in MDF full divider, one shared side-mounted terminal cup
- Drivers: Pair of Kicker 48CWRT104 CompRT 10 (DVC 4Ω), 400W RMS each, 13.35mm linear excursion, 3.4375 in top-mount depth
- Wiring: One cup feeds both positions in parallel, impedance set at the drivers, wire both identically
- Cabinet: 30 in W x 15 in D x 10.125 in H measured in down fire position, square corners
Financing available. Choose Shop Pay Installments at checkout.
Performance Optimized Down Fire Sealed Dual 10" Enclosure | Kicker CompRT
Proline X Performance Optimized Down Fire Dual 10" Sealed
Cut and tuned for a pair of Kicker CompRT 10s, model 48CWRT104
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 Kicker CompRT 10's own published numbers. A Performance box fits your subwoofer. A Performance Optimized box was built for it.
Built Around a Pair of Kicker CompRT 10s
Nothing about this cabinet is generic. Both baffles are bored to Kicker's 9.125 inch mounting hole specification, and the internal height is set by the driver's 3.4375 inch top mount depth. The footprint is the same 30 by 15 inches as the single driver Down Fire, standing 10.125 inches tall. It takes up no more floor area than the single, it simply stands taller, so measure vertical clearance before you order. This is a cargo floor or rear wall build, not an under seat build.
Each 48CWRT104 is a dual 4 ohm shallow mount rated 400 watts RMS. It uses an injection molded polypropylene cone, a Santoprene rubber surround with Kicker's red double stitching, the SoloKon integrated cone to backplate design, and Forced-Air Cooling that runs the motor roughly 20 percent cooler. The cone and surround are UV resistant, which is why this driver turns up in UTV and open cab builds as often as it does in trucks.
The Thiele-Small data this enclosure is cut from comes from Klippel measurement rather than a datasheet estimate: Fs 32.3 Hz, Qts 0.618, Vas 27.80 liters, Bl 19.158 Tm, Mms 150.85 g, Sd 349.67 cm², and 13.35mm of linear excursion. A 32.3 Hz free air resonance on a shallow 10 is genuinely low, and it is what lets a thin driver produce real low frequency output. Two of them put twice the cone area behind that same alignment.
Net Volume, Not Gross
Total internal gross volume is 1.646 cubic feet, split into two 0.823 cubic foot chambers. After displacement that is 0.793 cubic feet net per driver, 1.586 cubic feet net total. Each chamber produces Qtc 0.924, Fc 48.3 Hz, and a predicted anechoic F3 of 39.5 Hz, which is within a rounding error of the single driver Down Fire cabinet for this woofer. That match is deliberate. You are not getting a different sound, you are getting roughly 6 dB more of the same one.
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.
Kicker's published sealed range runs 0.4 to 1.25 cubic feet per driver, and the alignment does improve slightly with more air. On this footprint, though, every additional 0.1 cubic feet per chamber adds roughly an inch of cabinet height. Past about 0.8 per chamber a down fire dual stops being a down fire product in any useful sense, so 0.793 is where we stop. Run other volumes for yourself on our sealed box calculator.
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.
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 the cabinet airtight under sustained pressure cycling. Corners are square on Down Fire cabinets.
Double Baffle, Flush Recess
Both driver positions get a 1.5 inch baffle, 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 at each position.
Side-Mounted Terminal Cup
One Proline X ABS and carbon fiber composite cup with stainless hardware serves both chambers, pre-wired in 12 gauge OFC to both driver positions. Side mounted so it stays accessible with the baffles facing the floor.
Separate Chambers
A full height 3/4 inch MDF divider is bonded in, giving each driver its own sealed airspace and its own polyfill. Two drivers sharing one volume interact, with each compression stroke becoming the other's pressure environment, which smears transients and blurs the alignment either would have alone.
Power and Warranty
Kicker rates each 48CWRT104 at 400 watts RMS continuous. We recommend 300 to 400 watts RMS per driver on this alignment. Both drivers are dual 4 ohm, and the single cup feeds both positions in parallel, so you set the final impedance at the drivers by how you wire each one's coils. Wire both drivers identically; mismatched wiring between chambers splits power unevenly.
Mounting hardware is included, two sets of 8/32 threaded inserts with stainless steel machine screws, and polyfill damping is pre-installed in each chamber. The enclosure carries a 1 year limited warranty. Bring your own pair of Kicker 48CWRT104 subwoofers; the drivers are purchased separately.
Cut for the Driver, Not the Catalog
Two chambers, one driver each, both cut to the CompRT 10's own measured parameters. Machined on our ShopSabre routers and built one at a time in Tullahoma, Tennessee.
| Series | Proline X Performance Optimized Down Fire |
| Compatible Driver | Kicker 48CWRT104 CompRT 10 (DVC 4Ω) | Pair Required |
| Enclosure Type | Sealed | Dual Driver | Down Fire Geometry | Floor-Coupled |
| Chamber Configuration | Two Fully Separate Chambers | Full Divider | Single Shared Side-Mounted Terminal Cup |
| Firing Direction | Down Firing, Both Drivers Fire Toward The Floor |
| External Width | 30 Inches |
| External Depth | 15 Inches |
| External Height | 10.125 Inches |
| Dimension Reference | All External Dimensions Measured In Down Fire Position |
| Total Internal Gross Volume | 1.646 Cubic Feet |
| Per-Chamber Gross Volume | 0.823 Cubic Feet |
| Per-Chamber Net Volume | 0.793 Cubic Feet |
| Total Net Volume | 1.586 Cubic Feet |
| Kicker Published Sealed Range | 0.4 to 1.25 Cubic Feet Per Driver |
| Target System Qtc Per Chamber | 0.924 (Computed from Klippel-Measured T/S) |
| Predicted Fc Per Driver | 48.3 Hz |
| Predicted F3 Per Driver (Anechoic) | 39.5 Hz |
| Driver Fs | 32.3 Hz (Klippel) |
| Driver Qts | 0.618 (Klippel) |
| Driver Qes / Qms | 0.6635 / 9.097 (Klippel) |
| Driver Vas | 27.80 Liters / 0.982 Cubic Feet (Klippel) |
| Driver Bl | 19.158 Tm (Klippel) |
| Driver Mms | 150.85 g (Klippel) |
| Driver Cms | 0.161 mm/N (Klippel) |
| Driver Re | 7.945 Ohm (Klippel) |
| Driver Sd | 349.67 cm² (Klippel) |
| Driver Xmax | 13.35mm Linear (Klippel) |
| Voice Coil Configuration | Dual 4-Ohm Per Driver, Final Impedance Set At The Drivers |
| Recommended Power Per Driver | 300-400 Watts RMS (Kicker Rated: 400W RMS Continuous) |
| Mounting Depth (Each) | 3.4375 Inches Top-Mount (Kicker Spec) |
| Woofer Opening (Each) | 9.125 Inches (Kicker Spec) |
| Standoffs | None, Cabinet Sits Flat In The Down Fire Position |
| Material | Langboard Elite 3/4" MDF |
| Construction | ShopSabre CNC | V-Groove and Dado Joinery | Perimeter Cross-Brace |
| Panel Thickness | 3/4 Inch |
| Front Baffle | Double-Layer 1.5" MDF (Two 3/4" Sheets Bonded) at Both Driver Positions |
| Chamber Divider | 3/4" MDF Full Bonded Panel |
| Corner Profile | Square (Down Fire Series Standard) |
| Driver Mounting | 8/32 Threaded Inserts | Stainless Steel Machine Screws Included | 2 Sets |
| Terminal Cup | One Proline X ABS/Carbon Fiber Composite | Side Mounted | Serves Both Chambers |
| Internal Wiring | 12 Gauge OFC, Pre-Wired To Both Driver Positions |
| Damping | Polyfill Pre-Installed Per Chamber |
| Carpet | Plush Black |
| Weight | 44 lb |
| Bundle Options | Enclosure Only (Bring Your Own Pair of 48CWRT104) |
| Warranty | 1-Year Limited (Enclosure) |
| Built In | Tullahoma, Tennessee, USA |
01Is it a sealed driver?
Efficiency bandwidth product places the motor before anything else is decided.
02What the box does to it
0.79 cu ft against a 35.4 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 13.35 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.
| Param | Value | Unit | Note |
|---|---|---|---|
| Fs | 28.70 | Hz | free-air resonance |
| Qts | 0.486 / 0.618 | D2 / D4 | |
| Vas | 35.36 / 27.80 | L | equivalent compliance |
| Sd | 349.7 | cm² | effective piston area |
| Xmax | 13.35 | mm | one-way linear travel |
| Pe | 400 | W | continuous RMS |
| SPL | 84.0 | dB | 1 W / 1 m, derived from T/S |
Driver parameters as published by Kicker published Klippel T/S sheet. 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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