JL Audio 10TW3 - D4 in Proline X Micro Series EnclosureJL Audio 10TW3 - D4 in Proline X Micro Series EnclosureAlpine in Proline X Micro Series EnclosureJL Audio 10TW3 - D4 in Proline X Micro Series Enclosure

Micro Series · Datasheet

Micro Series 12" Sealed Enclosure - Fits JL Audio 12TW3 Single 12" Sealed enclosure

Net volume
0.80 Cubic Feet
Max mounting depth
3.5 Inches
External dimensions
26 Inches W × 14.75 Inches H × 6.75 Inches D
Front baffle
1.5 Inches (Double-Layer Stack Fab)
Buy at Audio Intensity
  • Best For: Behind-seat and under-seat truck installs, compact trunk builds needing accurate 12" bass
  • Power: Rated for up to 400W RMS (JL Audio 12TW3)
  • Topology/Class: Sealed / Double-Layer Stack Fab / Dowel Reinforced / Front-Fire or Downfire
  • Sonic Character: Tight, accurate, musical. 0.80 cu ft hits JL Audio's published optimal sealed volume exactly

Technical specifications

Compatible DriverJL Audio 12TW3-D4 / 12TW3-D8
Enclosure TypeSealed
Internal Volume (Net)0.80 Cubic Feet
MaterialLangboard Elite 3/4" MDF
ConstructionCNC-Cut Stack Fab / Dado Joinery / Dowel Reinforced
Front Panel Thickness1.5 Inches (Double-Layer Stack Fab)
External Width26 Inches
External Height14.75 Inches
External Depth6.75 Inches
Max Mounting Depth3.5 Inches
Woofer Opening11-5/8" Tab-Ear Cutout: Direct Fit JL Audio 12TW3
Driver Mounting8/32 Threaded Inserts: Stainless Machine Screws Included
Terminal CupProline X Terminal Cup: Pre-Wired
Internal Wiring12-Gauge OFC (Oxygen-Free Copper)
PolyfillPre-Installed
Firing DirectionFront-Firing or Downfiring
Downfire FeetIncluded
FinishPlush Black Automotive Carpet
Warranty2 Years: Proline X / Audio Intensity
Made InTullahoma, Tennessee, USA

Performance in this enclosure

Net airspace
0.80
cu ft per chamber
System Qtc
0.94
sealed
Half power
38.0
Hz · F3
Xmax at
733
W RMS · no filter
With 25 Hz subsonic
794
W RMS · +8%
Amplifier
400
W RMS recommended
This enclosure holds 0.80 cu ft net per chamber. In it the JL Audio 12TW3-D4 runs a system Qtc of 0.94 with half power at 38.0 Hz, and the cone reaches its 15.2 mm travel limit at 733 W, above the driver’s 400 W thermal rating, so heat stops you before travel does. Run a subsonic filter at 25 Hz and that becomes 794 W — +61 W, or 8 percent more power for the same 15.2 mm of travel.

01Is it a sealed driver?

Efficiency bandwidth product places the motor before anything else is decided.

EBP = Fs ÷ Qes = 47.4
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 D4 47.4
D4 · EBP 47.4
EBP under 50 means a motor that wants a sealed load. The 12TW3-D4 sits at 47.4, inside that band, which is why this is a sealed build rather than a ported one.

02What the box does to it

0.80 cu ft against a 48.7 L Vas.

α = Vas ÷ Vb = 2.15  ·  Fc = Fs√(α+1) = 47 Hz  ·  Qtc = 0.94
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
D4 · Qtc 0.94, Fc 47 Hz, F3 38.0 Hz
The box lifts resonance from 26.5 Hz free-air to 47 Hz and half power lands at 38.0 Hz, anechoic, before any cabin gain.

03The watts that reach Xmax (in this enclosure)

Travel scales with the square root of power, so there is one wattage that puts the cone exactly on 15.2 mm — and a bigger one once a subsonic filter stops it wasting travel below the passband.

PXmax = 733 W unfiltered  →  794 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 4 8 12 16 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 15.2 mm 733 W reaches Xmax here
D4 · 733 W, no filterD4 · 794 W with subsonic at 25 Hz, 24 dB/octXmax 15.2 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 15.2 mm. Unfiltered that is 733 W, reached first at 31 Hz. It sits above the 400 W the driver can take thermally, so the voice coil gives up before the suspension does. The dashed traces are the same driver behind a subsonic filter at 25 Hz, 24 dB/oct: stopping the cone wasting travel below the passband lets it take 794 W before hitting the same 15.2 mm. That is 8 percent more amplifier for the price of one filter setting.
ParamValueUnitNote
Fs26.46Hzfree-air resonance
Qts0.531D4
Vas48.73Lequivalent compliance
Sd539.0cm²effective piston area
Xmax15.2mmone-way linear travel
Pe400Wcontinuous RMS
SPL83.9dB1 W / 1 m, derived from T/S

Driver parameters as published by jlaudio.com. Curves computed against this enclosure’s actual net airspace.

Installer's take

The JL Audio 12TW3 is the 10TW3's larger sibling. Same concentric tube motor architecture, same tab-ear mounting system, same no-pole-vent design that lets you mount it within 1/4" of the rear wall. What changes is the cone area, the Vas at 48.7 liters, and the optimum sealed volume at 0.80 cubic feet. This enclosure delivers exactly that. When the box volume matches the driver's published optimum, the system Qtc lands where JL Audio modeled it, and the driver performs the way the data sheet says it will. The tab-ear mounting system on the 12TW3 is the one detail that separates it from most 12" shallow drivers and the reason the threaded inserts matter more here than on a standard-flange driver. The four ears extend beyond the cutout diameter and are made from injection-molded plastic. If you run tapered wood screws into those ears, you are applying outward wedge pressure on plastic tabs under sustained vibration. They will crack over time. The threaded inserts on this enclosure eliminate that problem entirely. The 12TW3 mounts with machine screws threading into steel, the ears clamp down evenly, and the seal against the baffle gasket is consistent across all four mounting points. If you ever pull the driver for a system change, reinstall goes back to the same torque with no degradation. The 6.75" total depth is what separates this from the Wavtech builds in the same series. More depth means more panel rigidity without having to rely entirely on stack-fab mass, the geometry itself helps. The double-layer 1.5" baffle is still warranted at 400 watts RMS on a 12" driver, but the side and rear panels have more structural depth to work with than a 4.5" enclosure. This is the quietest, most acoustically inert design in the Micro Series lineup. The no-pole-vent design is worth noting for install planning. Unlike most subwoofers, the 12TW3 has no vent on the rear of the motor. You do not need to leave a gap between the back of the magnet and the rear wall of the enclosure. That internal space is available as usable airspace, already factored into the 0.80 cubic foot net volume calculation.

Questions

Does this enclosure include the JL Audio 12TW3 subwoofer?

No. This is an enclosure-only product engineered specifically for the JL Audio 12TW3-D4 and 12TW3-D8. Both impedance variants share identical physical dimensions and fit this enclosure. The enclosure ships pre-wired with the Proline X terminal cup, 8/32 threaded inserts, stainless machine screws, pre-installed polyfill, and rubber feet for downfiring installation.

Will this fit behind the seat of my truck?

At 6.75" total depth, 26" wide, and 14.75" tall, this enclosure is designed for behind-seat and under-seat truck applications. It fits behind the rear seat in most full-size crew cab and extended cab trucks including the Ford F-150, F-250, Silverado, Sierra, Ram 1500, and Ram 2500. Seat floor clearance varies by model and trim level. Measure the available depth at both the front and rear of the install location and confirm the 26" width clears any seat track hardware before purchasing.

What makes the stack-fab construction on this enclosure different from a standard MDF box?

Stack-fab construction layers and bonds CNC-cut MDF panels in overlapping orientations, building panel mass and eliminating single-layer glue joints at critical surfaces. This enclosure goes further by reinforcing the stack-fab assembly with dowels throughout the build. Dowels add mechanical alignment and shear resistance beyond what dado joinery and adhesive alone provide. Locking the panel stack against lateral movement under the sustained pressure a sealed enclosure generates at volume. The combination of stack-fab layering, dado joinery, adhesive, and dowel reinforcement produces a structure that holds its geometry and acoustic seal over years of real-world use.

Can I mount this as a downfiring enclosure?

Yes. The enclosure ships with rubber feet for downfiring installation. No additional hardware required. Downfiring couples bass output with the vehicle floor, which in truck cabs and SUVs produces a more evenly distributed low-frequency response throughout the cabin. The JL Audio 12TW3's no-pole-vent design means there are no motor ventilation concerns in either orientation, the driver can mount as close as 1/4" from the rear wall without any airflow restriction.

Why does this enclosure have a 1.5" double-layer baffle?

The baffle is the highest-stress panel in any sealed enclosure. It carries the driver's mechanical mounting load and sustains the full acoustic pressure differential between the sealed interior and exterior on every bass transient. At 400 watts RMS on a 12" cone, a single 3/4" panel will resonate at frequencies within the driver's operating range, adding coloration to the output. Two CNC-cut Langboard Elite panels bonded to 1.5 inches effectively double the panel mass, eliminating baffle resonance at the structural level. The dowel reinforcement throughout the stack-fab assembly locks the double-layer baffle against any lateral movement under sustained excursion load.

What amplifier power does the 12TW3 require?

The JL Audio 12TW3 is rated at 400 watts RMS with a recommended amplifier range of 200–400 watts RMS. For the D4 wired to 2 ohms, a monoblock stable at 2 ohms in the 300–400 watt RMS range is the practical target. Avoid amplifiers that significantly exceed 400 watts RMS at the final impedance, the 12TW3's thermal limits are the ceiling, and overpowering a shallow-mount driver in a compact sealed enclosure is the primary failure mode. Monoblock amplifiers from the Audio Intensity collection can be filtered by stable impedance and output to match this driver correctly.

Can a different 12" subwoofer be used in this enclosure?

The baffle is machined to the 12TW3's tab-ear cutout geometry at 11-5/8" with mounting points positioned for the TW3's four-ear spacing. Drivers with a standard round flange will not seat correctly against this baffle. The internal volume of 0.80 cubic feet is also specific to the 12TW3's Thiele-Small parameters. Substituting a driver with significantly different Vas or Qts will produce a Qtc that deviates from that driver's design target and degrades performance predictably.

Where is the Proline X Micro Series 12" enclosure built?

Every Proline X enclosure is CNC-cut and hand-assembled in Tullahoma, Tennessee on ShopSabre CNC routers. Langboard Elite MDF is used throughout, a named, mill-documented panel with published density, internal bond, and screw-holding specifications. Internal volume, tab-ear cutout geometry, dado joint depth, baffle layer count, and terminal placement are held to spec on every unit. Proline X is the enclosure brand owned and manufactured by Audio Intensity.

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