Proline X PO 12-S W TW3 sealed wedge enclosure, front baffle with gloss black insert and pre-wired leads, 28.25 by 14.5 inches. Optimized for JL Audio TW3.Proline X PO 12-S W TW3 sealed wedge enclosure, side profile with recessed terminal cup, 4.5 inch top, 9.89 inch base, 14.5 inches tall. Optimized for JL Audio TW3.

Performance Optimized · Datasheet

Performance Optimized Wedge Sealed 12" Enclosure | JL Audio 12TW3 Single 12" Sealed enclosure

Net volume
0.801 Cubic Feet (JL Spec: 0.80)
Cutout
11.625 Inches
External dimensions
28.25 Inches W × 14.5 Inches H × 4.5 Inches / 9.89 Inches D
Front baffle
Vertical Trunk-Lid-Side Woofer Mounting Face
Buy at Audio Intensity
  • Best For: JL Audio 12TW3-D4 Shallow-Mount Trunk-Fit Builds (Trucks, Sports Cars, Low-Clearance Installs)
  • Net Volume: 0.801 cu ft (JL Spec: 0.80 | 0.83 cu ft Gross)
  • Driver Match: JL Audio 12TW3-D4 (Dual 4Ω: Only Version JL Offers)
  • Construction: Ultra-Shallow Rear-Firing Wedge | 4.5" Top Depth | Tab-Ear Ready

Technical specifications

Enclosure TypeSealed | Wedge Geometry | Rear-Firing Trunk-Load | Ultra-Shallow
Driver-Specific FitmentJL Audio 12TW3-D4 (DVC 4Ω: only version JL offers)
Internal Volume (Gross)0.83 Cubic Feet
Internal Volume (Net After Displacement)0.801 Cubic Feet (JL Spec: 0.80)
Baffle ConfigurationVertical Trunk-Lid-Side Woofer Mounting Face
MaterialLangboard Elite 3/4" MDF
Front Baffle ConstructionDouble-Layer 1.5" MDF (Two 3/4" Sheets Bonded)
JoineryV-Groove and Dado (CNC-Cut)
ConstructionShopSabre CNC / Shallow Compound Cuts / Tab-Ear Baffle
External Width28.25 Inches
External Height14.5 Inches
External Depth (Top)4.5 Inches
External Depth (Bottom)9.89 Inches
Baffle Angle~20° From Vertical (Seat-Side Face)
Mounting Hole Diameter11.625 Inches
Mounting Hardware8/32 Threaded Inserts | #8 Pan-Head Stainless Screws (TW3 Tab-Ear Compatible)
Terminal CupProline X ABS/Carbon Fiber Composite | 12g OFC Pre-Wired
DampingPolyfill Pre-Installed
Recommended Power300-400 Watts RMS (100-400W JL Spec Range)
Carpet FinishDark Gray Trunkliner (Standard) or Plush Black
Acrylic InsertBlack, Blue, Red, White, or None
Bundle OptionsBox Only | Add a JL Audio 12TW3-D4 Driver
Warranty1-Year Limited (Enclosure)
ManufacturedTullahoma, 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 12TW3-D4 is the driver you buy when you need a real 12" but your vehicle won't fit a real 12" enclosure. Simple as that. It's not a compromise driver, JL engineered the TW3 series specifically for shallow-mount applications, using their patented concentric tube cone architecture to push the motor structure forward into the cone body itself. The result is 12" of cone area with just 3.5" of mounting depth, and honestly, higher excursion capability than the regular W3v3 despite the shallow packaging.

The trade-off, if you want to call it one: 400 watts RMS instead of 500. The TW3 doesn't take the same kind of power as a W3 or W6, so if you're building a max-output SPL system, this isn't the right driver. But if you're building a musical daily driver in a vehicle where a normal 12" cabinet is a non-starter. F-150 SuperCab, RAM 1500 Quad Cab, Miata trunk, Corvette C7 rear cargo, anywhere ceiling clearance or depth clearance is limited, the TW3 gets you real bass without contorting your vehicle around the enclosure.

The math on this box lands right where it should. 0.83 cu ft gross minus 0.029 cu ft driver displacement = 0.801 cu ft net. JL's published sealed spec for the 12TW3-D4 is 0.80 cu ft net. Direct hit. Same as the 10W3 and 12W6 wedges we build, we're not designing around a target we chose. We're building to JL's own spec so the driver behaves the way JL's engineers intended.

The wedge geometry is where this box gets special. 28.25" wide by 14.5" tall, but only 4.5" deep at the top of the box, tapering to 9.89" at the bottom. That 4.5" top depth is unusual. It's shallower than most people's rear seat back leans away from the trunk floor. It slides under decklids and parcel shelves that a full-depth wedge could never fit under. Combined with the TW3's own 3.5" mounting depth, this is one of the most vehicle-friendly full-size 12" enclosures on the market.

Because the top of the box is so shallow, panel-to-air ratio is high, meaning the ratio of MDF surface area inside the box to the air volume itself is higher than in a deeper cabinet. That's why we're building this out of Langboard Elite MDF instead of commodity 3/4" board. Denser panels mean less resonance, and in a shallow cabinet, panel resonance would color the sound more than in a deep box. Attention to material matters here.

The tab-ear mounting on the TW3 is worth understanding. Instead of a continuous perimeter mounting flange like a regular subwoofer, the TW3 has three plastic tabs sticking out from the driver frame. Maximizes cone area in a small footprint, but the tabs are plastic and can crack over time if you use the wrong screws. JL specifies #8 or #10 pan-head screws, flat-headed, no taper. Countersunk screws will wedge the plastic ears outward under road vibration and split them. The Proline X cabinet ships with pan-head stainless screws and threaded inserts positioned for the TW3's tab pattern. Don't substitute drywall screws or tapered wood screws.

The DVC 4-ohm coil configuration is the only impedance JL offers for the TW3. No SVC, no D2, no D8. That gives you two wiring options via the terminal cup: parallel for a 2-ohm load (higher output, standard class D monoblock territory) or series for an 8-ohm load (rare, mainly for bridged high-voltage or Class AB setups). 90+ percent of installs will run parallel wiring at 2 ohms with a 300-400 watt RMS monoblock. That's the sweet spot.

Power target: JL specs 100 to 400 watts RMS. Sweet spot is 300-400. Feed it more than 400 sustained and you're pushing thermal limits, the TW3's smaller voice coil doesn't have the thermal mass of the W3v3 or W6v3. Match with a well-regulated 400-watt monoblock class D amp at 2 ohms and this driver will run happily for the life of the vehicle. Set your low-pass around 80-100 Hz depending on your front-stage capability.

Same JL crossover warning as always: no passive crossover coils in series with this driver. Use your amp's active low-pass filter.

If you've got a truck, a sports car, or any low-clearance install where a normal 12" won't work, this is the JL-spec box for the TW3.

Questions

What size enclosure does the JL Audio 12TW3-D4 need?

JL Audio publishes exactly one recommended sealed enclosure volume for the 12TW3-D4: 0.80 cubic feet net internal. The Audio Intensity Performance Optimized Wedge Sealed 12 for TW3 delivers 0.83 cubic feet gross internal, which after subtracting the 12TW3-D4's 0.029 cubic foot driver displacement lands at 0.801 cubic feet net. Essentially exact match to JL's published spec. Because the TW3 series was engineered from the ground up for small-enclosure operation, this is the volume where the driver performs as JL's engineers intended.

What are the dimensions of the Performance Optimized Wedge Sealed 12 for the JL TW3?

The Performance Optimized Wedge Sealed 12 for JL Audio TW3 measures 28.25" wide x 14.5" tall externally, with an ultra-shallow wedge depth of just 4.5" at the top and 9.89" at the bottom. The angled seat-side face sits approximately 20 degrees back from vertical, matching typical rear seat back lean angles. The 4.5" top depth is engineered around the JL TW3's 3.5" shallow-mount depth for tight-clearance installs.

Why choose the JL Audio 12TW3-D4 shallow-mount subwoofer?

Choose the JL Audio 12TW3-D4 when you need a full-size 12" subwoofer in a vehicle where a standard-depth 12" enclosure won't fit. Pickup trucks, sports cars, low-clearance sedan trunks, and SUV cargo areas with height restrictions are all natural fits. The TW3 uses JL's patented concentric tube cone architecture to deliver 12" of cone area with just 3.5" of mounting depth, while actually enabling greater excursion than the standard W3v3. The Performance Optimized Wedge Sealed 12 for TW3 pairs this shallow driver with an equally shallow enclosure (4.5" top depth) so the entire system fits where deeper builds cannot.

How much power can the JL Audio 12TW3-D4 handle?

The JL Audio 12TW3-D4 handles 400 watts RMS continuous, with JL recommending amplifier power in the 100 to 400 watt RMS range. For balanced output and long-term thermal reliability, pair with a clean, well-regulated monoblock amplifier delivering 300 to 400 watts RMS at your chosen impedance. Feed more than the rated 400 sustained watts and you risk pushing the TW3's smaller voice coil past its thermal limits.

What impedance options are available for the JL Audio 12TW3?

JL Audio offers the 12TW3 in only one impedance configuration: 12TW3-D4 (Dual 4-ohm voice coils). There is no SVC version, no D2 version, and no D8 version. The dual 4-ohm coils can be wired in parallel for a 2-ohm total load (ideal for class D monoblocks stable at 2 ohms, delivering maximum output) or in series for an 8-ohm total load (used mainly with bridged high-voltage or Class AB amp configurations). Most installs will run parallel-wired at 2 ohms.

What is the mounting depth of the JL Audio 12TW3-D4?

The JL Audio 12TW3-D4 has a mounting depth of just 3.5 inches, with a mounting hole cutout of 11.625 inches. JL's tab-ear mounting design uses three plastic tabs extending outward from the driver frame (not a continuous perimeter flange), requiring #8 or #10 pan-head screws, never countersunk tapered screws, which can crack the plastic tabs under vibration. The Performance Optimized Wedge Sealed 12 for TW3 ships with pan-head stainless steel screws and threaded inserts positioned for the tab-ear pattern.

Can the JL Audio 12TW3-D4 be used with a passive crossover?

No. JL Audio recommends against using this subwoofer with a passive crossover (coil), as this type of device will adversely affect performance. Instead, use your amplifier's active low-pass filter to set the sub's upper cutoff frequency. Typically between 80 and 100 Hz for musical accuracy in a full-range system.

Where is the Performance Optimized Wedge Sealed 12 for JL TW3 manufactured?

The Performance Optimized Wedge Sealed 12 for JL Audio TW3 is manufactured in Tullahoma, Tennessee, USA at the Audio Intensity facility. Every panel is CNC-cut on ShopSabre routers from premium Langboard Elite MDF, with the shallow wedge geometry requiring precise compound cuts to maintain both the JL-spec 0.80 cu ft target volume and the correct 20-degree seat-side mating angles. Assembly begins after your order is placed. Expect a 2 to 5 business day build window before shipment.

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