Proline X
Performance Optimized Down Fire Sealed 10" Enclosure | Kicker CompRT
SKU: PO 10-S DF CompRT
- Alignment: 0.80 cu ft net, Qtc 0.922, Fc 48.2 Hz, F3 40.0 Hz, computed from Klippel-measured T/S
- Driver: Kicker 48CWRT104 CompRT 10 (DVC 4Ω), 400W RMS, 13.35mm linear excursion, 3.4375 in top-mount depth
- Wiring: Dual 4-ohm coils, 2 ohms in parallel or 8 ohms in series at the driver
- Build: V-groove and dado joinery, double-layer 1.5 in front baffle, perimeter cross-brace, side-mounted 12g OFC terminal cup
- Cabinet: 30 in W x 15 in D x 6.125 in H measured in down fire position, square corners
Financing available. Choose Shop Pay Installments at checkout.
Performance Optimized Down Fire Sealed 10" Enclosure | Kicker CompRT
Proline X Performance Optimized Down Fire 10" Sealed
Cut and tuned for the Kicker CompRT 10, 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 the Kicker CompRT 10
Nothing about this cabinet is generic. The baffle is 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 finished cabinet stands 6.125 inches tall on a 30 by 15 inch footprint, which puts it under seats and behind back benches where a conventional box will not go.
The 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 shows 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 the single parameter that lets a thin driver reach like a full depth one.
Net Volume, Not Gross
We build this cabinet at 0.80 cubic feet net out of 0.833 gross. Kicker's published sealed range for the CompRT 10 runs 0.4 to 1.25 cubic feet, so 0.80 sits in the middle of the window the manufacturer sanctions. That volume produces Qtc 0.922, Fc 48.2 Hz, and a predicted anechoic F3 of 40.0 Hz: a controlled alignment just above unity, with a modest lift near the corner frequency and the composed character the CompRT is known for.
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.
Going larger is possible but not worth it in this format. At 1.25 net, the top of Kicker's range, the alignment improves to Qtc 0.826 with F3 at 37.8 Hz. That buys 2.2 Hz of extension in exchange for nearly two additional inches of cabinet height. On a down fire shallow build meant to disappear under a seat, height is the entire point, so the trade goes the wrong way.
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. If you want to see what a different volume does to the same driver, run the numbers on our sealed box calculator.
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
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, which matters on a cabinet only 6.125 inches tall.
Side-Mounted Terminal Cup
Proline X ABS and carbon fiber composite cup with stainless hardware, pre-wired in 12 gauge OFC. Side mounted so it stays accessible with the baffle facing the floor.
Perimeter Cross-Brace
A perimeter cross-brace ties the long panels together across the 30 inch span. Short cabinets leave little room for bracing geometry, so the brace and the double baffle carry the structural load a taller box would spread out.
Power and Warranty
Kicker rates the 48CWRT104 at 400 watts RMS continuous. We recommend 300 to 400 watts RMS on this alignment. The driver is dual 4 ohm, so you set the final impedance at the driver: 2 ohms with the coils in parallel, 8 ohms in series. Most single driver builds want the 2 ohm load.
Mounting hardware is included, 8/32 threaded inserts with stainless steel machine screws, and polyfill damping is pre-installed. The enclosure carries a 1 year limited warranty. Bring your own Kicker 48CWRT104; the driver is purchased separately.
Cut for the Driver, Not the Catalog
This cabinet exists for one driver and one orientation. It is 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) |
| Enclosure Type | Sealed | Down Fire Geometry | Floor-Coupled |
| Firing Direction | Down Firing, Driver Fires Toward The Floor |
| External Width | 30 Inches |
| External Depth | 15 Inches |
| External Height | 6.125 Inches |
| Dimension Reference | All External Dimensions Measured In Down Fire Position |
| Internal Volume (Gross) | 0.833 Cubic Feet |
| Internal Volume (Net) | 0.80 Cubic Feet |
| Kicker Published Sealed Range | 0.4 to 1.25 Cubic Feet |
| Target System Qtc | 0.922 (Computed from Klippel-Measured T/S) |
| Predicted Fc | 48.2 Hz |
| Predicted F3 (Anechoic) | 40.0 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, 2Ω Parallel or 8Ω Series At The Driver |
| Recommended Power | 300-400 Watts RMS (Kicker Rated: 400W RMS Continuous) |
| Mounting Depth | 3.4375 Inches Top-Mount (Kicker Spec) |
| Woofer Opening | 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) |
| Corner Profile | Square (Down Fire Series Standard) |
| Driver Mounting | 8/32 Threaded Inserts | Stainless Steel Machine Screws Included |
| Terminal Cup | Proline X ABS/Carbon Fiber Composite | Side Mounted | One Cup |
| Internal Wiring | 12 Gauge OFC, Pre-Wired |
| Damping | Polyfill Pre-Installed |
| Carpet | Plush Black |
| Weight | 28 lb |
| Bundle Options | Enclosure Only (Bring Your Own 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
0.80 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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