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Proline X PO 12T-S W TW3 sealed wedge enclosure, product photos pending. Placeholder graphic reading Photos Coming Soon.

Performance Optimized · Datasheet

Performance Optimized Wedge Wide Sealed Triple 12" Enclosure JL Audio 12TW3 · Triple 12" Sealed enclosure

Net volume
0.800 cu ft per driver, 2.40 cu ft total, after both dividers and JL Audio's published 0.029 cu ft displacement per driver
Max mounting depth
3.50 in required; 3.04 in clearance above the motor against the raked rear panel
External dimensions
44 in W × 17 in at the seat face H × 13.03 in at the base D
Front baffle
1.5 in double baffle, outer layer machined as a flush recess
Buy at Audio IntensityFactory-direct, ships from Tullahoma
JL Audio 12TW3Buy at Audio Intensity
  • Best For: Triple JL Audio 12TW3 SUV Cargo-Floor Builds
  • Net Volume: 0.800 cu ft per Driver (2.40 cu ft Net Total)
  • Driver Match: Three JL Audio 12TW3 (matched set), matched
  • Construction: 3 Chambers | 44" Wide Wedge | V-Groove/Dado | Double 1.5" Baffle | 3 Terminal Cups

Spec of record

Technical specifications

SpecificationValue
SeriesProline X Performance Optimized Wedge Wide
Compatible DriverJL Audio 12TW3, quantity 3, matched. Direct fit
ConfigurationTriple 12 inch sealed wedge, 3 chambers, 1 driver per chamber
Mounting PositionSUV cargo floor, raked face against the rear seat back
Firing DirectionRearward toward the liftgate. Not a down fire design
External Width44 in
External Height17 in at the seat face
External Depth13.03 in at the base, tapering to 6.84 in at the top
Internal Volume, Gross2.58 cu ft total
Internal Volume, Net Acoustic0.800 cu ft per driver, 2.40 cu ft total, after both dividers and JL Audio's published 0.029 cu ft displacement per driver
Driver Mounting Depth3.50 in required; 3.04 in clearance above the motor against the raked rear panel
Alignment Per Driver12TW3-D4 Qtc 0.943, fc 47.0 Hz, F3 38.0 Hz anechoic
Woofer Openings3 at 11.625 in
Woofer LayoutOne row across the face
Frame Outer Diameter13.2 in
Fs / Qts / Qes26.5 Hz / 0.531 / 0.558
Vas / Sd / Xmax48.7 L / 539 cm2 / 15 mm
Driver Power Handling400 W RMS per driver, 1200 W RMS for the set of 3 (thermal rating)
Recommended Amplifier280-400 W RMS per driver, 840-1,200 W RMS for the full set
Parameter SourceJL Audio published specifications
MaterialLangboard Elite MDF
ConstructionCNC cut, V-groove and dado joinery
Panel Thickness0.75 in
Front Baffle1.5 in double baffle, outer layer machined as a flush recess
Internal BracingTwo full-height 3/4 in dividers
Driver MountingThreaded inserts, stainless machine screws included
Terminal CupsThree Proline X ABS and carbon fiber composite, on the rear panel, one per chamber, pre wired 12 gauge OFC
Acrylic InsertGloss black acrylic baffle insert standard
DampingLight polyfill wall lining in every chamber, does not alter acoustic volume
CarpetPlush black
Shipping Weight67 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
0.800
cu ft per driver
System Qtc
0.94
sealed
Half power
38.0
Hz · F3
Xmax at
733
W RMS per driver · no filter
With 25 Hz subsonic
794
W RMS per driver · +8%
Amplifier, per driver
280–400
W RMS recommended
This enclosure holds 0.800 cu ft net per driver. 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 per driver, 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 per driver — +61 W, or 8 percent more power for the same 15.2 mm of travel.

00Sizing the amplifier

Every wattage on this panel is per driver. This cabinet holds three, so the amplifier feeds all three at once.

Per driver 280–400 W RMS  ×  3 drivers  =  full set 840–1,200 W RMS
Look for a mono amplifier rated 840–1,200 W RMS at the load your coil version wires to. The top is the driver’s 400 W thermal rating; with the 25 Hz subsonic set the cone still has travel to spare there, reaching Xmax only at 794 W. Below the bottom of the range it will play, just with less headroom; above the top you are buying power the drivers cannot use.

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 12TW3-D4 47.4
12TW3-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

0.800 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
12TW3-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. Figures are JL Audio’s published parameters. This cabinet holds three drivers in three separate sealed chambers of 0.800 cubic feet each, the volume plotted here.

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 per driver unfiltered  →  794 W per driver 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
12TW3-D4 · 733 W, no filter12TW3-D4 · 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 per driver, 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 per driver 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
Qts0.53112TW3-D4
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 JL Audio 12TW3-D4 published specifications. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

Start with the size. 0.800 cubic feet per driver puts the 12TW3 at Qtc 0.943, resonance 47.0 Hz, half power 38.0 Hz anechoic. That matches the single sealed box we build for this driver, so the wide box and the single sound alike per driver. Butterworth on these figures wants 2.23, which on this platform means deeper than the 23 in platform allows. It is a firm lift near resonance, 0.9 dB above flat.

Measure the base depth, not the top. This cabinet is 13.03 in deep where it meets the floor, 6.84 at the top, 44 wide and 17 tall. In an SUV the 44 has to clear between the rear wheel wells at floor height, the base depth is measured from the seat back with the seat upright and latched, and the 17 has to clear the cargo cover.

All three terminal cups are on the rear panel, and the rear panel is the face that goes against the seat back. Wire all three before the box goes in, with enough slack to slide it into place; once the raked face is against the seat you cannot reach them.

Each driver has its own chamber. The outer two are set 0.44 in toward the ends of their chambers so the 13.2 in frames clear each other; that is deliberate, not an off-center cut.

The load depends on which coil version you run, so settle the coil before you buy the amplifier; the wiring section lists the clean loads for each version.

Power. Size the amplifier for the set, not one driver: 280 to 400 W RMS per driver is 840 to 1,200 W RMS across all 3.

JL Audio publish no Qms for the 12TW3, so the printed Qts could not be cross-checked.

Polyfill is in as a wall lining in every chamber. Do not add more: it makes the box act larger and walks Qtc off 0.94.

Before you order

Questions

Does this fit the JL Audio 12TW3, and its coil versions?

Yes. Each opening is cut to 11.625 in for the 13.2 in frame, and the 3.50 in deep motor clears the raked rear panel with 3.04 in to spare. Coil versions of the JL Audio 12TW3 share the frame, cutout and mounting depth, so any of them drops in. The alignment on this page is computed on the 12TW3-D4 parameters.

Run three matched drivers, same model and same coil, so every chamber sees the alignment on this page.

Why 0.800 cubic feet per driver, and what alignment does it target?

On JL Audio's published Fs 26.5 Hz, Qts 0.531 and Vas 48.7 liters, 0.800 cubic feet per driver gives Qtc 0.943, system resonance 47.0 Hz and half power 38.0 Hz.

The cabinet is sized to the single sealed box we build for this driver, 0.80 cubic feet per driver, to keep it realistic for a cargo floor. Maximally flat would need 2.23 cubic feet per driver; this size trades a little low end for a compact box and a firm lift near resonance, 0.9 dB above flat.

What amplifier power should I run, and how should I wire it?

JL Audio rates the 12TW3 at 400 watts RMS per driver. Recommended amplifier: 280 to 400 W RMS per driver, 840 to 1,200 W RMS for the full set of 3.

Loads depend on the coil version you run. Three dual 4 ohm drivers, coils in series, all three in parallel: 2.67 ohms; coils in parallel, all three in series: 6 ohms. Dual 2 ohm: 1.33 ohms or 3 ohms the same two ways. Single 4 ohm: 1.33 ohms in parallel, 12 ohms in series. Use the lower load only on an amplifier rated stable there.

Will it fit my SUV?

It is 44 inches wide, 17 tall and 13.03 deep at the base, tapering to 6.84 at the top. Measure between the rear wheel wells, the floor depth with the seat upright, and the height under your cargo cover.

The raked face goes against the seat back and the woofers fire toward the liftgate.

Why are all three terminal cups on the back?

Each driver has its own sealed chamber, and the center chamber has no side wall to take a cup. Putting all three on the rear panel gives a matching set, one cup per chamber.

Wire them at the amplifier end; there is no cross-chamber wiring inside the cabinet.

What is the expected low-frequency extension?

Anechoic F3 is 38.0 Hz per driver with system resonance at 47.0 Hz.

Those figures exclude cabin gain. An SUV cabin adds real output below about 50 Hz, so in-vehicle response runs deeper than the numbers above.

Do I need to add polyfill or damping?

No. Polyfill is already installed as a light wall lining in every chamber, and the quantity is chosen so it does not change the acoustic volume.

Do not add more. Packing a sealed box makes it behave as though it were larger, which moves the alignment away from 0.800 cubic feet per driver.

Are the drivers included?

No. This is an enclosure only. You receive the cabinet finished in plush black carpet with the gloss black acrylic baffle insert, three pre-wired terminal cups on the rear panel, the polyfill lining in place, threaded inserts and stainless machine screws.

Bring three matched JL Audio 12TW3 drivers. The cabinet is cut direct fit to them, not a general purpose 12 inch box.

Same series, same size

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