Proline X Performance P12 - S Sealed Enclosure for 12" Subwoofers|Proline X|Audio Intensity

Proline X

Proline X P12-S | Single 12" Sealed Subwoofer Enclosure | V3

SKU: P12-S III G

QUICK SPECS

Best For: Single 12" sealed installs — accurate bass, compact footprint
Volume: 1.25 ft³ Net
Tuning: N/A — Sealed
Sonic Character: Tight, transient-accurate, flat response

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.

$ 179.99

Carpet Options

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Proline X P12-S | Single 12" Sealed Subwoofer Enclosure | V3

Enclosure Type Sealed

External Dimensions 19.5" x 14.5" x 11.5"

Net Volume 1.25cu ft

Tuning Frequency N/A

Cutout Diameter 11.15"

Front Panel Thickness .75"

Max Mounting Depth 10"

INSTALLER'S TAKE

The 10" max mounting depth is the standout spec on this enclosure. Most single 12" sealed boxes in this price range are built around shallower drivers — you hit a depth limit the moment you step up to a high-excursion motor. The P12-S is dimensioned to handle those drivers without modification, which opens up the compatible driver list considerably.
At 1.25 ft³ net the volume is well-matched to most standard 12" drivers in a sealed alignment. You are not padding an oversized box or fighting an undersized one. At 19.5" wide and 11.5" deep this is one of the more compact single 12" sealed boxes in the Performance Series lineup, which makes it a strong candidate for trunk installs in sedans and coupes where depth is limited.

Product Details

Proline X P12-S

Single 12" Sealed Subwoofer Enclosure | V3

1.25 ft³ Net Sealed Alignment 10" Max Depth 0.75" Single Baffle Langboard Elite MDF Built in Tennessee

Accurate 12" Bass. Compact Enough to Work in Most Vehicles.

The Proline X P12-S is a single 12" sealed enclosure built for installs where accuracy and a controlled response curve are the priority. The 12" driver in sealed alignment produces the most balanced bass profile in the Performance Series lineup — enough output to carry the full bass load in a daily driver system, enough low-frequency extension to cover virtually all musical content, and enough transient accuracy to integrate cleanly with a front stage without requiring heavy DSP correction. No port resonance. No tuning peak. No frequency-specific coloration.

At 19.5" wide, 14.5" tall, and 11.5" deep, the P12-S fits in most standard trunk setups without requiring custom fabrication. The 10" max mounting depth is one of the deeper specifications in the single 12" sealed category — it covers high-excursion SQ-oriented motors that exceed the depth limit of shallower 12" sealed boxes and opens up the compatible driver list considerably.

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 Sealed for a 12" Daily or SQ Build

The 12" driver in sealed alignment is the most versatile bass configuration in car audio. It produces enough output for daily high-volume listening, enough low-frequency extension to reach the bottom of virtually any musical content, and a response profile flat enough to integrate cleanly with almost any front stage. For installs running a Goldhorn DSP or any active processor, sealed alignment is the preferred format — the predictable rolloff responds accurately to DSP correction and gives you full control over the final response without fighting a ported tuning peak.

At 1.25 ft³ net, the P12-S places most standard 12" drivers in the middle of their recommended sealed range. No damping material required. No volume correction needed. The enclosure is correctly sized for the driver category — not undersized to hit a compact target and not oversized to inflate the spec sheet.

Transient Accuracy

Sealed alignment preserves the start-stop precision that produces tight, musical bass. Notes have distinct attack and decay. The P12-S produces low frequencies that integrate with the front stage rather than competing with it — the bass is part of the music, not a separate event in the trunk.

Flat, Predictable Response

No port resonance. No tuning peak. No frequency-specific coloration. The P12-S produces a smooth, controlled rolloff below resonance that integrates cleanly with any front stage and responds accurately to DSP equalization and bass boost.

10" Max Mounting Depth

One of the deeper specs in the single 12" sealed category. High-excursion SQ-oriented motors that exceed the depth limit of shallower 12" sealed boxes are viable here. The driver list for the P12-S includes drivers that most single 12" sealed enclosures on the market cannot physically accommodate.

DSP-Friendly Alignment

Sealed enclosures exhibit a predictable 12 dB/octave rolloff that responds accurately to DSP bass boost and crossover adjustments. Running a Goldhorn DSP or any active processor? Sealed is the alignment that gives you the most control over the final response.

Construction: The Proline X Standard on Every Panel

The P12-S uses the same construction methodology as every enclosure in the Proline X Performance Series. Langboard Elite MDF. V-groove and dado joinery. In-house terminal cup. Hand-assembled in Tennessee. The variables are dimensions, volume, and alignment. The build quality 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 directly from Langboard's published mill data.

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. For a sealed enclosure, joint integrity is the most important construction variable — a single air leak degrades output and response accuracy across the entire bass range. Every seam on the P12-S is mechanically locked before adhesive is applied. The box does not leak. The response does not change over time as joints loosen.

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 over time.

ShopSabre CNC Routers

Every panel is machine-cut on ShopSabre industrial CNC routers. Consistent geometry, no hand-cut variance, no gaps at the joints. The internal volume of every P12-S is identical to spec across every unit produced.

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 for a stealth appearance. 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 P12-S is one of the more compact single 12" sealed enclosures in the Performance Series. At 19.5"W x 14.5"H x 11.5"D it fits in most standard sedan and truck trunk setups. The 11.5" depth is compact for a 12" sealed enclosure — most trunks that will fit a 12" at all will fit the P12-S without custom fabrication.

Dimensional Specifications

External Dimensions: 19.5" W x 14.5" H x 11.5" D

Net Internal Volume: 1.25 ft³

Tuning Frequency: N/A — Sealed

Subwoofer Cutout: 11.15"

Max Mounting Depth: 10"

Front Panel Thickness: 0.75" Single Baffle

Driver Compatibility

The P12-S accommodates any 12" subwoofer with a cutout diameter at or below 11.15" and a mounting depth at or below 10". 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 P12-S:

Prodigy NB2-12D4 → Image Dynamics ID12 V4 → Prodigy NB3-12D4 → Arc Audio ARC12 D2 →

Always verify cutout diameter and mounting depth against your specific driver's published specifications before ordering.

Ideal Install Applications

Standard Trunk Build

At 19.5" wide and 11.5" deep, the P12-S fits in most standard sedan and truck trunk configurations without custom fabrication. The compact depth makes it one of the more versatile single 12" sealed options in the Performance Series.

SQ Competition Builds

Sealed alignment, 1.25 ft³ net volume, and 10" max mounting depth make the P12-S the correct enclosure for SQ competition builds running high-excursion 12" drivers where accuracy and front stage integration are the priority.

DSP-Controlled Systems

The flat, predictable sealed rolloff makes the P12-S the preferred enclosure format for systems running a Goldhorn DSP or any active processor. Sealed alignment responds accurately to DSP correction and equalization — you tune the response rather than fight the box.

Daily Driver Systems

Enough output for real bass impact at daily listening levels, accurate enough to work across all music genres without sounding genre-specific. The P12-S is a strong daily driver enclosure for listeners who want bass that sounds like bass — not a resonance.

Accurate 12" Bass. Tennessee-Built. Shipping Included.

The Proline X P12-S is a single 12" sealed enclosure built to a spec, not a price point. Langboard Elite MDF. V-groove and dado joinery. 10" max mounting depth. In-house terminal cup. Hand-assembled in Tennessee and inspected before it ships.

If you need accurate, controlled 12" bass in a compact footprint — this is the correct enclosure. $179.99 Dark Gray Trunkliner. $189.99 Plush Black. Shipping included.

Specifications

Material	Langboard Elite MDF, 3/4" (18mm)
Enclosure Type	Sealed
Net Internal Volume	1.25 ft³
Tuning Frequency	N/A
External Dimensions	19.5" W x 14.5" H x 11.5" D
Subwoofer Cutout	11.15"
Max Mounting Depth	10"
Front Panel Thickness	0.75" Single Baffle
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

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 — 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.