Proline X
Proline X P15-S | Single 15" Sealed Subwoofer Enclosure | V3
SKU: P15-S III-G
- Best For: Single 15" sealed installs — maximum cone area, accurate bass, deep low-frequency extension
- Volume: 2.0 ft³ Net
- Tuning: N/A — Sealed
- Sonic Character: Deep, authoritative, flat response
Financing available — choose Shop Pay Installments at checkout.
Proline X P15-S | Single 15" Sealed Subwoofer Enclosure | V3
Proline X P15-S
Single 15" Sealed Subwoofer Enclosure | V3
Maximum Cone Area. Sealed Accuracy. Built to Last.
The Proline X P15-S is a single 15" sealed enclosure built for installs that need the output and low-frequency authority of the largest common subwoofer format — in a controlled, accurate alignment. At 2.0 ft³ net and sealed alignment, the P15-S gives a 15" driver the air space it needs to produce deep, authoritative bass with a flat, predictable response curve. No port resonance. No tuning peak. No frequency-specific coloration. The 15" cone moves significantly more air per excursion than any smaller driver — in sealed alignment, that output advantage is delivered with the same transient accuracy and DSP-tunability that sealed enclosures are known for.
At 19" wide, 17" tall, and 15" deep, the P15-S fits in most full-size sedan and truck trunks without custom fabrication. The 9" max mounting depth covers the majority of standard 15" drivers. For installs where you need the physical impact and low-frequency extension that only a 15" driver delivers — but want accuracy and control rather than a resonance — this is the correct enclosure.
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 a 15" Driver in Sealed Alignment
The argument for a sealed 15" comes down to one specific performance combination: the cone area and air displacement advantage of a 15" driver, delivered with the transient accuracy and flat response profile of a sealed enclosure. Most builders who choose a 15" driver go ported for maximum output. The sealed option is for a different listener — one who wants the physical presence and low-frequency reach of a 15" without the port resonance, the ported tuning peak, or the larger enclosure depth that a ported 15" requires.
At 2.0 ft³ net, the P15-S places most standard 15" drivers in the center of their recommended sealed range. The 15" cone at this volume produces output levels that exceed a dual 12" sealed configuration — with a single driver, a single terminal connection, and a simpler install. For installs where depth is available and output is the priority but accuracy cannot be sacrificed, the sealed 15" is the most capable single-driver sealed configuration in the Performance Series.
Maximum Single-Driver Cone Area
A 15" cone has roughly 55% more surface area than a 12" driver. In sealed alignment, that translates directly into more output, deeper low-frequency extension, and greater physical impact — all delivered with the flat, controlled response that sealed enclosures produce.
Deep Low-Frequency Extension
The 15" driver reaches sub-bass frequencies that smaller drivers in sealed enclosures cannot match at equivalent output levels. The P15-S produces bass below 30Hz with authority — the kind of physical presence that requires cone area, not just power.
Sealed Accuracy at 15" Scale
Sealed alignment preserves the transient accuracy that produces tight, musical bass at any output level. The P15-S delivers the physical impact of a large-format driver without the port resonance or tuning-specific coloration that ported 15" builds produce.
DSP-Friendly Alignment
The predictable 12 dB/octave sealed rolloff responds accurately to DSP bass boost and crossover adjustments. Running a Goldhorn DSP or any active processor? Sealed alignment gives you full control over the final response without fighting a ported tuning peak.
Construction: The Proline X Standard at 15" Scale
The P15-S uses the same Langboard Elite MDF and V-groove and dado joinery construction as every enclosure in the Proline X Performance Series. At 19" wide and 15" deep with a 15" motor generating sustained pressure on every panel, the construction standard that holds up in compact 8" builds is the same standard required here — and the P15-S is built to it without exception.
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. A 15" driver in a sealed enclosure generates significant sustained pressure on every panel simultaneously at high output levels. Every seam on the P15-S is mechanically locked before adhesive is applied — the joint integrity does not depend on adhesive condition alone. The box does not flex. The acoustic seal does not degrade over time.
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 P15-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 — regardless of enclosure size.
Dark Gray Trunkliner or Plush Black
Both finish options are professionally applied. Dark Gray Trunkliner blends with factory trunk materials for a clean, 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 P15-S fits in most full-size sedan and truck trunk configurations. At 19"W x 17"H x 15"D, the 17" height and 15" depth are the critical dimensions — verify both against your available trunk space before ordering.
Dimensional Specifications
External Dimensions: 19" W x 17" H x 15" D
Net Internal Volume: 2.0 ft³
Tuning Frequency: N/A — Sealed
Subwoofer Cutout: 14.1"
Max Mounting Depth: 9"
Front Panel Thickness: 0.75" Single Baffle
Driver Compatibility
The P15-S accommodates any 15" subwoofer with a cutout diameter at or below 14.1" and a mounting depth at or below 9". 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 P15-S:
Prodigy NB5-15D2 → Image Dynamics IDMAX15 V4 →Always verify cutout diameter and mounting depth against your specific driver's published specifications before ordering.
Ideal Install Applications
Full-Size Trunk Build
At 19" wide and 15" deep, the P15-S fits in most full-size sedan and truck trunk configurations. The 17" height is the most constraining dimension in tighter trunk environments — measure available height before ordering.
SQ and DSP-Controlled Systems
Sealed alignment and 2.0 ft³ net volume make the P15-S the correct enclosure for 15" drivers in sound quality and DSP-controlled builds where the goal is maximum output with accurate, tuneable response rather than port-tuned SPL.
High-Output Daily Systems
The 15" format in sealed alignment produces the most output available from a single-driver sealed configuration in the Performance Series. For daily systems where physical bass impact is the priority and accuracy cannot be sacrificed, the P15-S is the top of the sealed lineup.
Step Up From Dual 12" Sealed
For builds running the P12D-S that need more output and deeper extension from a single driver rather than two — the P15-S is the natural progression. More cone area, more output, simpler wiring, in a comparable trunk footprint.
Maximum Sealed Output. Tennessee-Built. Shipping Included.
The Proline X P15-S is the most capable single-driver sealed enclosure in the Performance Series. Langboard Elite MDF. V-groove and dado joinery. 9" max mounting depth. In-house terminal cup. Hand-assembled in Tennessee and inspected before it ships.
Maximum cone area. Sealed accuracy. The top of the Performance Series sealed lineup. $219.99 Dark Gray Trunkliner. $229.99 Plush Black. Shipping included.
| Material | Langboard Elite MDF, 3/4" (18mm) |
| Enclosure Type | Sealed |
| Net Internal Volume | 2.0 ft³ |
| Tuning Frequency | N/A |
| External Dimensions | 19" W x 17" H x 15" D |
| Subwoofer Cutout | 14.1" |
| Max Mounting Depth | 9" |
| 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 |
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 — 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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