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Proline X
Proline X P8-P | Single 8" Ported Subwoofer Enclosure | V3
SKU: P8-P III G
QUICK SPECS
- Best For: High-output daily use / SPL-focused builds
- Volume: 0.75 ft³ (Net)
- Tuning: 36Hz
- Sonic Character: Aggressive, Deep, High-Impact
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.
$ 169.99
Financing available — choose Shop Pay Installments at checkout.
Proline X P8-P | Single 8" Ported Subwoofer Enclosure | V3
Enclosure Type
Ported
External Dimensions
19" x 11" x 13"
Net Volume
.75cu ft
Tuning Frequency
36hz
Cutout Diameter
7.25"
Front Panel Thickness
.75"
Max Mounting Depth
6.125"
INSTALLER'S TAKE
Product Details
Specifications
Materials
Proline X P8-P
Single 8" Ported Subwoofer Enclosure | V3
0.75 ft³ Net
36Hz Tuning
Ported Bass Reflex
0.75" Single Baffle
Langboard Elite MDF
Built in Tennessee
Maximum Output From a Single 8". Properly Tuned.
The Proline X P8-P is a single 8" slot-ported enclosure built for installs that need the most output a single 8" driver can produce. At 0.75 ft³ net and tuned to 36Hz, this enclosure gives an 8" driver the air space and port geometry to operate at its efficiency peak — strong output through the upper bass range, usable extension into the low 30s, and a response curve that works across music genres without being tuned for just one.
At 19" wide, 11" tall, and 13" deep, the P8-P fits in most standard trunk setups without requiring custom fabrication. The 6.125" max mounting depth covers most standard 8" drivers including high-excursion SQ motors. Port geometry is CNC-cut to exact dimensions — tuning is consistent unit to unit with no hand-cut variance in port length or cross-section.
Every panel is CNC-cut from Langboard Elite MDF to exact internal volume and assembled by hand in our Tennessee facility. A single recessed ABS/Carbon Fiber Composite terminal cup handles wiring, pre-wired with 12g OFC speaker wire. Finish options are Dark Gray Trunkliner or Plush Black. Shipping is included.
Why Ported at 36Hz for a Single 8"
A sealed 8" enclosure at 0.45 ft³ produces accurate, controlled bass with a flat response. The P8-P trades some of that precision for significantly more output and lower frequency extension — the correct tradeoff when the install goal is impact rather than accuracy. The ported alignment at 36Hz pushes the efficiency peak into the upper sub-bass range, where the majority of bass content in music lives.
At 36Hz, port output peaks at a frequency that covers kick drum fundamentals, bass guitar low notes, and the sub-bass range in hip-hop and electronic music. Driver excursion is minimized at tuning — the port handles the acoustic load — which means the driver produces more output with less mechanical stress at the frequencies that matter most.
Extended Low-Frequency Output
Ported alignment at 36Hz extends usable bass output significantly lower than a sealed equivalent. The P8-P produces audible, impactful output well below 40Hz — territory a sealed 8" at 0.45 ft³ cannot reach at the same efficiency.
Higher Efficiency Per Watt
Ported enclosures convert amplifier power to acoustic output more efficiently than sealed designs near the tuning frequency. More output from the same amplifier — a meaningful advantage in installs where amplifier headroom is limited.
Reduced Excursion at Tuning
At and near 36Hz, the port handles the acoustic load and driver excursion drops significantly. Less mechanical stress on the driver at the frequencies where 8" drivers are most vulnerable to over-excursion.
36Hz — Balanced and General-Purpose
36Hz provides strong output through the upper sub-bass without the port velocity issues that come with tuning too low on a single 8" enclosure. It is a genre-agnostic tuning point that performs across hip-hop, rock, and electronic equally.
Construction: The Same Standard Across Every Proline X SKU
The P8-P uses the same construction methodology as every enclosure in the Proline X Performance Series. The variables are dimensions, volume, and alignment. The build quality — Langboard Elite MDF, V-groove and dado joinery, in-house terminal cup — is consistent across the entire lineup.
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. The specifications below are pulled from Langboard's published mill data — not marketing copy.
Langboard Elite — Published Mill Data
Density: 48.5 lbs/ft³ — higher density means less porosity, better screw retention, and reduced resonance
Internal Bond: 200 psi — resistance to delamination under sustained bass pressure cycling
Modulus of Elasticity: 410,000 psi — panel stiffness under load; less flex means less resonance
Face Screw Holding: 325 lbs — baffle hardware stays locked under vibration
Edge Screw Holding: 250 lbs — joint integrity at every panel edge connection
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 mechanical interlock that resists shear forces regardless of glue condition. Every corner is locked. Every seam is airtight. Port geometry is CNC-cut to exact dimensions — no hand-cut variance in port length or cross-section means tuning frequency is consistent unit to unit.
In-House ABS/Carbon Fiber Composite Terminal Cup
The terminal cup is built in-house at our Tennessee facility. The ABS/Carbon Fiber Composite recessed cup features stainless steel hardware, aluminum landing plates, and copper ring terminals, pre-wired with 12g OFC speaker wire. The recessed mount protects terminals from cargo contact. Copper ring terminals provide a clean, corrosion-resistant connection that does not loosen under vibration.
ShopSabre CNC Routers
Every panel and port is machine-cut on ShopSabre industrial CNC routers. Consistent geometry, no hand-cut variance. Port length, cross-section, and panel dimensions are identical across every unit.
Hand-Assembled in Tennessee
Every enclosure is hand-assembled at our Tennessee facility and inspected before it ships. No overseas manufacturing. No batch assembly shortcuts.
Dark Gray Trunkliner or Plush Black
Both finish options are professionally applied. Dark Gray Trunkliner blends with factory trunk materials. Plush Black delivers the traditional aftermarket look. Both are durably bonded for long-term wear.
Shipping Included
No freight charges at checkout. The price you see is the price you pay. The enclosure ships assembled and ready to install.
Fitment Guide
The P8-P is sized for standard trunk installs. At 19"W x 11"H x 13"D it fits in most sedan and truck trunk configurations without custom fabrication. The 13" depth is the critical dimension — measure your available trunk depth before ordering.
Dimensional Specifications
External Dimensions: 19" W x 11" H x 13" D
Net Internal Volume: 0.75 ft³
Tuning Frequency: 36Hz
Subwoofer Cutout: 7.25"
Max Mounting Depth: 6.125"
Front Panel Thickness: 0.75" Single Baffle
Driver Compatibility
The P8-P accommodates any 8" subwoofer with a cutout diameter at or below 7.25" and a mounting depth at or below 6.125". Verify both dimensions against your driver's published specifications before ordering.
Compatible Drivers
The following drivers are available from Audio Intensity and are compatible with the P8-P:
Image Dynamics ID8 V4 → Prodigy NB2-8D4 → Image Dynamics IDQ8 V4 → Prodigy NB5-8D4 → Arc Audio Arc Series 8" →Always verify cutout diameter and mounting depth against your specific driver's published specifications before ordering.
Ideal Install Applications
Standard Trunk Builds
At 19" wide and 13" deep, the P8-P fits in most standard sedan and truck trunk configurations. It is the natural step up from the P8-S when output is the priority over accuracy.
Daily Driver Systems
The 36Hz tuning and 0.75 ft³ volume produce a bass response that works across music genres without requiring system-specific tuning. A strong general-purpose single 8" ported build for daily use.
High-Output Compact Builds
For installs where a 10" or 12" enclosure is too large but a sealed 8" is not enough — the P8-P fills that gap. Maximum output from the 8" driver format in a footprint that fits where larger boxes do not.
Behind Rear Seat
At 11" tall and 13" deep, the P8-P fits behind most rear seats in full-size sedans and trucks. Confirm your available depth before ordering — 13" is deeper than the sealed P8-S.
Maximum 8" Output. Tennessee-Built. Shipping Included.
The Proline X P8-P is a single 8" ported enclosure built to a spec, not a price point. Langboard Elite MDF. V-groove and dado joinery. CNC-cut port geometry. In-house terminal cup. Hand-assembled in Tennessee and inspected before it ships.
If you need the most output a single 8" driver can produce in a compact footprint, this is the correct enclosure. $169.99 Dark Gray Trunkliner. $179.99 Plush Black. Shipping included.
| Material | Langboard Elite MDF, 3/4" (18mm) |
| Enclosure Type | Slot-Ported Bass Reflex |
| Net Internal Volume | 0.75 ft³ |
| Tuning Frequency | 36Hz |
| External Dimensions | 19" W x 11" H x 13" D |
| Subwoofer Cutout | 7.25" |
| Max Mounting Depth | 6.125" |
| Front Panel Thickness | 0.75" |
| Finish | Dark Gray Trunkliner / Plush Black (+$10) |
| Terminal Cup | ABS/Carbon Fiber Composite, recessed mount, stainless hardware, copper ring terminals |
| Wiring | Pre-wired 12g OFC speaker wire |
| Warranty | 1-Year Limited |
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 — 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.
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.
Shop By Series
Economy Series
Value Driven - Standard Output
Performance Series
High Output - Universal Ported & Sealed
Performance Optimized Series
Precision Tuned - Brand Specific Geometry
Performance Wedge Series
Angled Back - Truck & Hatchback Ready
Professional Series
Competition Grade - Double Baffle High SPL
Micro Series
Compact Sealed - Small Footprint Efficiency
Down Fire Series
Under Seat - Cargo Safe Down-Firing
Vehicle Specific Series
OEM Fitment - Stealth Truck & SUV Solutions
Loaded Series
Plug & Play - Subwoofer + Box Bundles
