Proline X subwoofer enclosures, CNC cut in Tullahoma, Tennessee
Built Different. Built Better.
Sealed, ported and down-firing enclosures built to the driver, not the shelf. This site is the engineering reference: every model's datasheet, series by series, with the numbers an installer compares on.
Proline X
Built to the driver, the vehicle or the space
Proline X is the subwoofer enclosure line designed and CNC cut by Audio Intensity in Tullahoma, Tennessee. It is not a brand we stock; it is what leaves our shop. Every cabinet is cut from 3/4" Langboard Elite MDF on our own ShopSabre routers, joined with dado and V-groove cuts or stack fabricated from layered panels, wrapped in black carpet, and fitted with a Proline X ABS and carbon-fiber composite terminal cup with stainless hardware and copper ring terminals. Sealed cabinets ship with polyfill; ported ones ship dry with their tuning stated.
The line is organised by how the cabinet is made, not by what it looks like. Performance is the universal cutout for a driver that is not settled. Performance Optimized is cut to one subwoofer's published parameters, and it is where most buyers end up because most already know what they own. Professional adds baffle thickness, bracing and port work for drivers built for output. Micro is the shallow-mount build for spaces a standard box will not fit, Vehicle Specific is cut to a particular truck or SUV, Down-Fire gathers every cabinet that fires into the floor, and Loaded is any of them with the driver installed and wired.
This site is the engineering reference for the line. Each series page explains the build standard and lists every model with the numbers an installer compares on: net volume, alignment and tuning, mounting depth, cutout and external dimensions. Each datasheet carries the spec of record for one cabinet and links to its sales page at Audio Intensity, where every Proline X enclosure is sold factory-direct.
Series
Proline X Enclosures
Micro Series
Compact sealed enclosures for shallow-mount and small-footprint installs.
The Micro Series exists for the space a standard subwoofer box will not go: behind the seat of a single cab, under a rear bench, in the shallow well behind a hatch. It is a line of sealed cabinets cut to shallow-mount drivers, and it starts from a plain admission. A compact box only works when the driver is compact too, so every Micro cabinet is designed around one named shallow-mount subwoofer rather than a size class. The internal volume, the baffle cutout and the bracing are solved from that driver's published Thiele-Small parameters, which is why the model table names the driver next to every cabinet.
- 18 models
- Sealed
- 10", 12", 15"
- Dual, Single
Performance Series
Universal sealed and ported enclosures in single and dual 8", 10", 12" and 15".
The Performance Series is the universal line: cabinets sized to a standard driver diameter and a known-good volume range rather than to one specific model. It is the right series when the driver is not settled yet, when it might change later, or when a buyer wants a properly built box for a subwoofer that is already in hand. Sealed and ported versions run from 6.5" through 15", in single and dual driver layouts, and every ported cabinet is tuned to 36 Hz, a universal point that covers most music without giving up the bottom octave.
- 22 models
- Ported and Sealed
- 6", 8", 10", 12", 15"
- Dual, Quad, Single, Triple
Performance Optimized
Driver-specific enclosures solved from the manufacturer's Thiele-Small parameters.
Performance Optimized is the build standard for a cabinet cut to one subwoofer. Where the Performance Series sizes a box to a driver diameter, a Performance Optimized cabinet takes a named model's published Thiele-Small parameters and solves the net volume, the alignment, the port where there is one and the baffle cutout for that driver alone. The datasheet names the subwoofer it was designed around, and the numbers on it only mean something against that driver. It is the largest part of the Proline X line because most buyers already know which subwoofer they own.
- 380 models
- Ported and Sealed
- 8", 10", 11", 12", 13", 15", 18"
- Dual, Single, Triple
Professional Series
Multi-layer baffle enclosures for high-output subwoofers.
The Professional Series sits at the top of the Proline X line. It is the enclosure standard for drivers that outgrow a trunk-sized cabinet: high-excursion, high-power subwoofers where the baffle has to hold the motor still and the port has to stay clean at the power the driver is actually run at. Like Performance Optimized, every Professional cabinet is solved to one driver's published Thiele-Small parameters. What the series adds is how heavily it is built and how large it is allowed to be.
- 15 models
- Ported and Sealed
- 8", 10", 12", 13", 15"
- Dual, Single
Loaded Series
Proline X enclosures with the matched subwoofer installed, wired and ready to connect.
A Loaded Series enclosure is a Proline X cabinet that arrives with its subwoofer already mounted, gasket-sealed against the baffle, wired to the terminal cup and tested, so the install is placement and two wires from the amplifier. Loaded is a way of buying rather than a separate build standard: every cabinet in this series belongs to one of the other Proline X series and is built to that series' specification, carrying that series' warranty. The datasheet states which series each loaded cabinet is built on.
- 24 models
- Ported and Sealed
- 8", 10", 12"
- Dual, Single
Down-Firing Series
Down-fire sealed and ported enclosures for cargo bays and behind-seat spaces.
A down-firing enclosure mounts the subwoofer on the bottom baffle so the cone faces the vehicle floor instead of the cabin. That does two things a rear-firing box cannot. The floor becomes part of the acoustic load, spreading bass more evenly through the cabin instead of aiming it at one trunk panel, and the cone sits underneath the cabinet where cargo, boots and dog crates cannot reach it. From above, a down-fire cabinet reads as a flat bench.
- 144 models
- Ported and Sealed
- 8", 10", 11", 12", 13", 15"
- Dual, Single, Triple
Vehicle Specific
Direct-fit enclosures for specific trucks, SUVs and Jeeps.
A universal enclosure is sized to a driver. A Vehicle Specific enclosure is sized to a vehicle. Factory cab interiors do not take a generic box cleanly: behind-seat cavities have their own depths, hump heights and panel angles, cargo floors slope, and wheel wells eat into the width. A cabinet that ignores those constraints either will not fit, blocks a factory function such as folding seats or tie-downs, or needs permanent modification to install.
- 1 models
- Sealed
- 12"
- Dual
Vehicle specific
Direct-fit enclosures by truck and SUV
Learning Center
Enclosure design, explained by the people who cut them
Passive vs Active Subwoofers
Complete comparison of passive vs active subwoofers covering amplification, installation requirements, performance differences, and cost considerations.
Subwoofer Impedance Guide
Complete subwoofer impedance guide explaining 2 ohm, 4 ohm, 8 ohm configurations, amplifier matching, and power delivery for optimal bass performance.
Subwoofer Magnet Types
Complete guide to subwoofer magnet types including ferrite, neodymium, and ceramic magnets, and their impact on performance, efficiency, and sound quality.
Ready to buy?
Every Proline X enclosure ships factory-direct from Audio Intensity. Datasheets here link straight to the sales page for that model.