Proline X

Performance Optimized Down Fire Sealed Dual 10" Enclosure | Kicker CompRT

SKU: PO 10D-S DF CompRT

QUICK SPECS

Alignment: 0.793 cu ft net per chamber, Qtc 0.924, Fc 48.3 Hz, F3 39.5 Hz - matches the single-driver DF cabinet
Chambers: Two fully separate sealed chambers, 3/4" 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
Cabinet: 30"W x 15"D x 10.125"H measured in down fire position, square corners

Shipping Included No freight charges at checkout. What you see is what you pay.

Built in Tennessee CNC cut from 3/4" Langboard Elite MDF. V-groove and dado joinery.

Advanced Terminal Cup Built in-house. ABS/Carbon Fiber. Stainless steel hardware. Copper ring terminals.

$ 299.99

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Performance Optimized Down Fire Sealed Dual 10" Enclosure | Kicker CompRT

$ 299.99

Enclosure Type Sealed

External Dimensions 30" W x 15" D x 10.125" H (measured in down fire position)

Net Volume 1.586 total / 0.793 per chambercu ft

Tuning Frequency N/A (Sealed)

Cutout Diameter Direct Fit

Front Panel Thickness 1.5"

Max Mounting Depth Direct Fit

INSTALLER'S TAKE

This is the dual for people who liked what the single CompRT did and want more of it. Same alignment, same character, twice the cone area. Each chamber lands at Qtc 0.924 with Fc 48.3 Hz and F3 39.5 Hz, which is within a rounding error of the single-driver cabinet. That is deliberate. You are not getting a different sound, you are getting about 6 dB more of the same one.

Separate chambers are non-negotiable on a dual sealed build. Two drivers sharing one volume interact: each driver's compression stroke becomes the other's pressure environment, which smears transients and blurs the alignment either would have on its own. A full-height bonded divider stops that. Each CompRT sees its own 0.793 net cubic feet, its own polyfill, and produces its own clean sealed alignment.

Be realistic about where this goes. At 10.125 inches tall it is not an under-seat box, which is what the single at 6.125 is for. This is a cargo floor or rear-wall build. The 30 by 15 footprint is unchanged, so it takes up no more floor area than the single, it just stands taller. Measure your vertical clearance before ordering.

On volume: 0.793 per chamber is where we stop. Kicker's range runs to 1.25 per driver and the alignment does improve slightly with more air, but every additional 0.1 cubic feet per chamber adds about an inch of cabinet height on this footprint. Past roughly 0.8 per chamber a down fire dual stops being a down fire product in any useful sense. If you want a larger per-driver volume, that is a different cabinet with different dimensions, not this one.

Wiring: one side-mounted cup feeds both driver positions in parallel. Set your final impedance at the drivers by how you wire each one's dual 4-ohm coils. Wire both identically, since mismatched wiring between chambers splits power unevenly. Target 300 to 400 watts RMS per driver.

Product Details

The Performance Optimized Down Fire Sealed Dual 10" Enclosure for the Kicker CompRT is a two-chamber sealed cabinet built around a pair of Kicker's shallow-mount CompRT 10" subwoofers. It carries the same 30 by 15 inch footprint as the single, standing 10.125 inches tall, and delivers roughly 6 dB more maximum output than one driver in the same alignment.

Each Kicker 48CWRT104 is a dual 4-ohm subwoofer rated 400 watts RMS with a 3-7/16 inch top-mount depth. Injection-molded polypropylene cone, Santoprene rubber surround with Kicker's signature red double stitching, 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.

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, giving each driver its own dedicated airspace. Two drivers sharing one sealed volume interact acoustically, with each driver's compression phase becoming the other's pressure environment, which smears transient response and blurs the alignment each would have on its own. Separate chambers eliminate that entirely.

The Thiele-Small data behind this design 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 allows this driver to reach real low-frequency output from a thin cabinet.

Total internal gross volume is 1.646 cubic feet split into two 0.823 cubic foot chambers, giving 0.793 cubic feet net per driver after displacement. Each chamber produces Qtc 0.924, Fc 48.3 Hz, and a predicted anechoic F3 of 39.5 Hz — effectively identical to the single-driver Down Fire cabinet for this driver. You get the same controlled alignment and the same character, with twice the cone area behind it.

Firing down into the floor, the sealed rolloff meets rising cabin gain below 60 Hz, and in-car response extends well below the anechoic figure.

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 double-layer 1.5 inch front baffles (two 3/4 inch sheets bonded) at both driver positions for maximum baffle rigidity and driver isolation. Corners are square on Down Fire cabinets. Both drivers fire down into the floor, and one side-mounted Proline X ABS/carbon fiber composite terminal cup serves both chambers, fed in parallel to both driver positions with 12 gauge OFC.

Bring your own pair of Kicker 48CWRT104 subwoofers. Both are dual 4-ohm, so you set your final impedance by how you wire the voice coils at each driver. Wire both drivers identically.

Manufactured in Tullahoma, Tennessee. 1-year enclosure warranty.

Specifications

Enclosure Type	Sealed \| Dual Driver \| Down Fire Geometry \| Floor-Coupled
Chamber Configuration	Two Fully Separate Chambers \| Full Divider \| Single Shared Side-Mounted Terminal Cup
Driver-Specific Fitment	Kicker 48CWRT104 CompRT 10 (DVC 4Ω) \| Pair Required
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
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)
Kicker Published Sealed Range	0.4 - 1.25 Cubic Feet Per Driver
Baffle Configuration	Down Firing - Both Drivers Fire Toward Floor
Material	Langboard Elite 3/4" MDF
Front Baffle Construction	Double-Layer 1.5" MDF (Two 3/4" Sheets Bonded) at Both Driver Positions
Chamber Divider	3/4" MDF Full Bonded Panel
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	10.125 Inches
Dimension Reference	All External Dimensions Measured In Down Fire Position
Mounting Hole Diameter (Each)	9.125 Inches (Kicker Spec)
Mounting Depth Required (Each)	3.4375 Inches Top-Mount (Kicker Spec)
Voice Coil Configuration	Dual 4-Ohm Per Driver - Final Impedance Set At The Drivers
Mounting Hardware	8/32 Threaded Inserts \| Stainless Steel Machine Screws Included \| 2 Sets
Terminal Cup	One Proline X ABS/Carbon Fiber Composite \| Side Mounted \| 12g OFC Pre-Wired to Both Driver Positions
Damping	Polyfill Pre-Installed Per Chamber
Recommended Power Per Driver	300-400 Watts RMS (Kicker Rated: 400W RMS Continuous)
Carpet Finish	Dark Gray Trunkliner (Standard) or Plush Black (+$10)
Bundle Options	Enclosure Only (Bring Your Own Pair of 48CWRT104)
Warranty	1-Year Limited (Enclosure)
Manufactured	Tullahoma, Tennessee, USA

Performance Graphs

Net airspace

0.79

cu ft per chamber

System Qtc

0.78–0.92

sealed

Half power

39.5–42.1

Hz · F3

Xmax at

257

W RMS · no filter

With 25 Hz subsonic

318

W RMS · +23%

Amplifier

200–400

W RMS recommended

This enclosure holds 0.79 cu ft net per chamber. In it the Kicker CompRT 10 (48CWRT102) runs a system Qtc of 0.78–0.92 with half power at 39.5–42.1 Hz, and the cone reaches its 13.35 mm travel limit at 257 W, below the driver’s 400 W thermal rating, so travel is what stops you here, not heat. Run a subsonic filter at 25 Hz and that becomes 318 W — +60 W, or 23 percent more power for the same 13.35 mm of travel.

01Is it a sealed driver?

Efficiency bandwidth product places the motor before anything else is decided.

EBP = Fs ÷ Qes = 48.7–56.8

D2 · EBP 56.8D4 · EBP 48.7

The CompRT 10 (48CWRT102) straddles the boundary at 48.7–56.8 depending on coil — part sealed-band, part transition. Either way it takes a sealed load happily; the coil you run shifts the alignment more than it shifts this verdict.

02What the box does to it

0.79 cu ft against a 35.4 L Vas.

α = Vas ÷ Vb = 1.57 · Fc = Fs√(α+1) = 46–48 Hz · Qtc = 0.78–0.92

D2 · Qtc 0.78, Fc 46 Hz, F3 42.1 HzD4 · Qtc 0.92, Fc 48 Hz, F3 39.5 Hz

The box lifts resonance from 28.7 Hz free-air to 46–48 Hz and half power lands at 39.5–42.1 Hz, anechoic, before any cabin gain. This enclosure ships without a driver, so both coil variants the maker offers are plotted. They do not load the same box the same way.

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.

P_Xmax = 257–313 W unfiltered → 318–337 W with a 25 Hz subsonic

D2 · 257 W, no filterD4 · 313 W, no filterD2 · 318 W with subsonic at 25 Hz, 24 dB/octD4 · 337 W with subsonic at 25 Hz, 24 dB/octXmax 13.35 mm one-way

Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 13.35 mm. Unfiltered that is 257 W, reached first at 20 Hz. It sits under the 400 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 318 W before hitting the same 13.35 mm. That is 23 percent more amplifier for the price of one filter setting.

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.

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

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.