Proline X
Proline X Enclosure | X Series | Fits Kicker Solo X 8" Subwoofer | Dual
SKU: Pro KIK 8D SOLO X - None
- Best For: Dual Solo-X 8" Builds | Low-Profile Installs
- Tuning: Optimized for Dual Solo-X 8"
- Net Volume: 1.75 cu ft
- Construction: Triple Face Baffle | Internal Bracing
Financing available — choose Shop Pay Installments at checkout.
Complete Your System
Proline X Enclosure | X Series | Fits Kicker Solo X 8" Subwoofer | Dual
Proline X X Series | Pro KIK 8D Solo X
Dual 8" Ported Enclosure | Built for Two Kicker Solo-X L7X Drivers
Two Drivers. One Spec. Recalculated From the Ground Up.
Running two Solo-X L7X 8" drivers in the same enclosure is not a matter of doubling a single-driver box. Combined cone displacement, combined excursion load, combined port velocity — every acoustic variable scales with driver count and has to be recalculated independently. The X Series dual 8" does that work.
The result is 1.75 cubic feet net internal volume tuned to 38 Hz with 36 square inches of port area — all derived from the combined Thiele-Small parameters of two Solo-X L7X 8" drivers running together. Internal volume is calculated after accounting for port displacement, triple-layer baffle thickness, and bracing material. Not before.
This is an enclosure-only product. You source the drivers — we handle the box. The square baffle cutouts are machined specifically to the L7X platform geometry. This enclosure is not cross-compatible with round 8" drivers.
Why the Dual 8" — And Why This Enclosure
The dual 8" X Series runs at 12" tall. Most dual-driver enclosures in this output class run 14" to 16" tall. That 2–4" difference is the reason to choose this configuration when height is the limiting dimension — behind-seat truck installs, shallow trunk builds, and low-profile dedicated audio builds where a taller enclosure is not an option. Two Solo-X 8" drivers in a correctly tuned 12"-tall enclosure deliver more combined cone area than a single 10" while keeping the profile lower than any dual-10" or dual-12" alternative.
The port area scales directly with the driver count. At 36 square inches — double the single 8" port area — the port handles the air volume two Solo-X 8" drivers generate at sustained high-power output without chuffing. The 38 Hz tuning places the enclosure's peak output in the low-frequency range where two 8" motors working together have the most to contribute.
1.75 ft³ — Dual-Driver Specific Volume
Not 2 × 0.88. The combined T/S parameters of two L7X 8" drivers in a shared enclosure produce a different optimal volume calculation than two independent single boxes. 1.75 ft³ net is where two drivers in this configuration operate in their linear range together.
38 Hz Tuning
One Hz lower than the single 8" configuration — a deliberate adjustment for the combined excursion load of two drivers. Two motors working together shift the optimal tuning point slightly downward, extracting more usable low-end output from the combined cone area.
36 sq in Port Area
Port area scales with the combined displacement of both drivers. At 36 square inches, air velocity stays below the chuffing threshold at the combined rated input range of two L7X 8" drivers — clean port output under sustained dual-driver load at competition power levels.
12" Height — The Competitive Advantage
The standout dimension on this enclosure is the 12" height. It fits where a dual-10" or dual-12" cannot — behind-seat truck installs and shallow trunk builds where vertical clearance is the binding constraint. Maximum dual-driver output, minimum height profile.
Construction: Scaled Up for Two Drivers
The Pro KIK 8D uses the same construction methodology as every Proline X enclosure — Langboard Elite MDF, V-groove and dado joinery, extensive internal bracing, in-house terminal cup, hand-assembled in Tennessee. Two drivers running together generate twice the pressure load on every panel joint and twice the motor mass cycling against the front baffle. The construction specs reflect that.
Triple-Layer Mounting Baffle — 2.25"
The dual 8" runs a triple-layer front baffle at 2.25" total thickness — a full 0.75" more than the single 8" configuration. Two L7X 8" motor assemblies cycling against the front panel at high excursion generate significantly more combined force than one. A dual-layer baffle is the correct spec for a single high-excursion motor. Two motors require the added mass and rigidity of a third layer. Both drivers stay seated, both gasket seals hold, and the baffle contributes nothing to the acoustic output.
Langboard Elite MDF — Named, Verified, Documented
Every panel is cut from Langboard Elite MDF — 3/4" (18mm) — a named, mill-documented panel stock produced in the United States. For a ported enclosure running two high-excursion motors at competition power levels, panel consistency sheet to sheet is not a cosmetic concern — it is a structural one.
Langboard Elite — Published Mill Data
Density: 48.5 lbs/ft³ — higher density means less porosity, better screw retention, and reduced panel resonance under sustained bass pressure cycling
Internal Bond: 200 psi — resistance to delamination; two drivers at high power double the pressure cycling through every panel joint on every bass note
Modulus of Elasticity: 410,000 psi — panel stiffness under load; critical when two motors are generating combined excursion force against every panel simultaneously
Face Screw Holding: 325 lbs — baffle hardware stays locked under the combined vibration load of two 225 oz. motors at excursion
Edge Screw Holding: 250 lbs — joint integrity at every panel edge connection throughout the enclosure's service life
V-Groove and Dado Joinery
Every panel joint uses V-groove and dado joinery — CNC-cut interlocking grooves that mechanically lock panels before adhesive is applied. The dado creates a tongue-and-groove interlock that resists shear forces regardless of glue condition over time. In a dual-driver ported enclosure, every joint is under twice the pressure load of a single-driver build on every bass transient. A leaking seam is a port you did not design — and with two drivers pressurizing the enclosure simultaneously, it will show up immediately.
Extensive Internal Bracing
The Pro KIK 8D is braced throughout the internal structure. Two 225 oz. motors cycling at their resonant frequency transmit force through every panel in the enclosure simultaneously on every bass transient. Bracing controls panel resonance at the structure level — the result is an enclosure that stays acoustically inert at sustained dual-driver output. The bass you hear comes from the drivers, not the box.
In-House Terminal Cups
Terminal cups are built in-house at our Tennessee facility. The recessed ABS/Carbon Fiber Composite cups feature stainless steel hardware, aluminum landing plates, and copper ring terminals, pre-wired with 12g OFC speaker wire. Copper ring terminals provide a corrosion-resistant connection that does not loosen under vibration over time.
ShopSabre CNC Routers
Every panel is machine-cut on ShopSabre industrial CNC routers at our Tennessee facility. Both square baffle cutouts are machined to direct-fit the Solo-X L7X 8" mounting flanges — no adapters, no modification required. The internal volume of every Pro KIK 8D is identical to spec.
Hand-Assembled in Tennessee
Every enclosure is hand-assembled and inspected at our Tennessee facility before it ships. No overseas manufacturing. No batch shortcuts. Each unit is built individually and checked for volume accuracy, joint integrity, and port clearance before leaving the floor.
Finish & Options
The Pro KIK 8D is finished in Plush Black carpet and available in two configurations. Both ship assembled and ready to install. Lead time is 2–4 business days.
Standard — Carpet Only
Plush Black carpet finish. Recessed ABS/Carbon Fiber Composite terminal cups. Pre-wired with 12g OFC speaker wire. Shipping included.
With Front Acrylic Panel
Everything in Standard plus laser-etched custom Proline X Hex and Flag acrylic graphics panel on the front baffle. Show-quality finish detail that identifies this as a purpose-built competition enclosure.
Every Proline X X Series enclosure carries a 2-year warranty covering manufacturing defects in materials and workmanship. Built in Tennessee and backed by Audio Intensity directly — no third-party claims process.
Fitment & Specifications
The Pro KIK 8D is purpose-built for two Kicker Solo-X L7X 8" drivers. Both square baffle cutouts are machined to the L7X platform geometry. This enclosure is not cross-compatible with round 8" drivers. Plan your amplifier selection around your final wiring impedance before ordering — two drivers give you multiple wiring options that produce different final loads.
Dimensional & Acoustic Specifications
External Dimensions: 34" W × 12" H × 18.25" D
Net Internal Volume: 1.75 ft³
Tuning Frequency: 38 Hz
Port Area: 36 sq in
Front Baffle Thickness: 2.25" Triple-Layer
Weight: 65+ lbs
Wiring Configurations
Two Single 2Ω Drivers — Parallel
Wire both drivers in parallel for a 1Ω final load. Requires an amplifier stable at 1Ω. Delivers maximum power from amplifiers rated at 1Ω.
Two Single 4Ω Drivers — Parallel
Wire both drivers in parallel for a 2Ω final load. The most common wiring scenario for dual-driver builds — compatible with the widest range of monoblock amplifiers.
Two Single 2Ω Drivers — Series
Wire both drivers in series for a 4Ω final load. Useful when your amplifier is not stable at lower impedances. Output will be lower than parallel configurations at the same amplifier.
Confirm Before You Order
Select your driver impedance based on your amplifier's stable output impedance — not its peak power rating. Contact us with your amplifier model and we will confirm the correct wiring plan before purchase.
Ideal Install Applications
Behind-Seat Truck Installs
The 12" height is the reason this configuration exists. It clears behind-seat floor-to-ceiling clearance in extended-cab and crew-cab trucks where a dual-10" or dual-12" at 14–16" tall will not fit. Verify your specific cab clearance — 12" is the constraint to check, not width.
Shallow Trunk Builds
At 18.25" deep and 12" tall, the Pro KIK 8D fits in shallow trunk builds where larger dual-driver configurations cannot go. The 34" width covers most sedan trunk openings — measure before ordering.
High-Output Daily Driver
Two correctly loaded Solo-X 8" drivers produce output that competes with single larger-format drivers in a significantly lower-profile enclosure. The dual 8" is the configuration for buyers who need maximum output without building tall.
Competition Builds
For competitors working within a height or class constraint, the Pro KIK 8D delivers dual-driver Solo-X performance from the smallest correctly tuned dual-8" enclosure these drivers' specifications allow.
Two Drivers. Built to Spec. Built in Tennessee.
The Proline X Pro KIK 8D is not two single boxes joined together. It is a dual-driver-specific enclosure recalculated from the ground up for two Solo-X L7X 8" drivers. Langboard Elite MDF. Triple-layer baffle. Extensive internal bracing. V-groove and dado joinery. Hand-assembled and inspected in Tennessee before it ships. Backed by a 2-year warranty.
You source the drivers. We handle the box. Standard $499.99 | With Acrylic Panel $549.99. Shipping included. 2–4 day lead time.
Audio Intensity and Proline X are not affiliated with Kicker. This enclosure is engineered to match the published Thiele-Small specifications of the Kicker Solo-X L7X 8".
| SKU | Pro KIK 8D Solo X |
| Enclosure Type | Ported / Vented |
| Configuration | Dual 8" |
| Compatible Driver | Kicker Solo-X L7X 8" × 2 |
| Driver Impedance | 1Ω DVC (49L7X81) or 2Ω DVC (49L7X82) — per driver |
| Net Internal Volume | 1.75 ft³ |
| Tuning Frequency | 38 Hz |
| Port Area | 36 sq in |
| External Dimensions | 34" W × 12" H × 18.25" D |
| Front Baffle | 2.25" Triple-Layer MDF |
| Internal Bracing | Extensive — Full Structure |
| Panel Material | Langboard Elite MDF 3/4" (18mm) |
| Joinery | V-Groove and Dado |
| Terminal Cups | Recessed ABS/Carbon Fiber Composite × 2 |
| Speaker Wire | 12g OFC — Pre-Wired |
| Finish | Plush Black Carpet |
| Weight | 65+ lbs |
| Warranty | 2 Years — Manufacturing Defects |
| Lead Time | 2–4 Business Days |
| Made In | Tennessee, USA |
| Shipping | Included — Lower 48 States (UPS Ground) |
Built From a Spec Sheet, Not a Sales Sheet
Every Proline X X 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 — 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 X 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.
Frequently Asked Questions
Is this a shared-chamber enclosure or does each driver get its own chamber?
How do I wire two Solo-X 8" drivers in this enclosure?
Why does the dual 8" use a triple-layer baffle instead of the dual-layer used on the single 8"?
Why choose the dual 8" over a single 10" or single 12"?
What amplifier do I need for this enclosure?
What is the lead time and how does shipping work?
Can I use this enclosure with a different 8" subwoofer brand or model?
How do I confirm this will fit my vehicle before ordering?
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