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Proline X PO 12T-S W VD12 sealed wedge enclosure, product photos pending. Placeholder graphic reading Photos Coming Soon.

Performance Optimized · Datasheet

Performance Optimized Wedge Wide Sealed Triple 12" Enclosure Skar Audio VD-12 · Triple 12" Sealed enclosure

Net volume
1.000 cu ft per driver, 3.00 cu ft total, after both dividers and an estimated 0.085 cu ft displacement per driver
Max mounting depth
4.95 in required; 3.73 in clearance above the motor against the raked rear panel
External dimensions
44 in W × 17 in at the seat face H × 15.17 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
Skar Audio VD-12Buy at Audio Intensity
  • Best For: Triple Skar Audio VD-12 SUV Cargo-Floor Builds
  • Net Volume: 1.000 cu ft per Driver (3.00 cu ft Net Total)
  • Driver Match: Three Skar Audio VD-12 (Dual 2 Ohm / Dual 4 Ohm), 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 DriverSkar Audio VD-12, 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 Depth15.17 in at the base, tapering to 8.98 in at the top
Internal Volume, Gross3.38 cu ft total
Internal Volume, Net Acoustic1.000 cu ft per driver, 3.00 cu ft total, after both dividers and an estimated 0.085 cu ft displacement per driver
Driver Mounting Depth4.95 in required; 3.73 in clearance above the motor against the raked rear panel
Alignment Per DriverVD-12 D2 Qtc 0.876, fc 56.2 Hz, F3 47.4 Hz; VD-12 D4 Qtc 0.961, fc 58.6 Hz, F3 46.9 Hz anechoic
Woofer Openings3 at 11.280 in
Woofer LayoutOne row across the face
Frame Outer Diameter12.6 in
Fs / Qts / Qes / Qms35.3 Hz / 0.550 / 0.620 / 4.420
Vas / Sd / Xmax43.5 L / 505 cm2 / 11 mm
Driver Power Handling500 W RMS per driver, 1500 W RMS for the set of 3 (thermal rating)
Recommended Amplifier290-410 W RMS per driver, 870-1,230 W RMS for the full set
Parameter SourceSkar 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 Weight75 lb
Warranty1 Year Limited
Built InTullahoma, Tennessee

Modelled response

Performance in this enclosure

Net airspace
1.000
cu ft per driver
System Qtc
0.88–0.96
sealed
Half power
46.9–47.4
Hz · F3
Xmax at
394
W RMS per driver · no filter
With 25 Hz subsonic
414
W RMS per driver · +5%
Amplifier, per driver
290–410
W RMS recommended
This enclosure holds 1.000 cu ft net per driver. In it the Skar Audio VD-12 D2 runs a system Qtc of 0.88–0.96 with half power at 46.9–47.4 Hz, and the cone reaches its 11.0 mm travel limit at 394 W per driver, below the driver’s 500 W thermal rating, so travel is what stops you here, not heat. A 25 Hz subsonic filter adds little here: 414 W per driver against 394 W, 5 percent. The box already resonates at 56–59 Hz, so its own rolloff has removed most of what the filter would have stopped.

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 290–410 W RMS  ×  3 drivers  =  full set 870–1,230 W RMS
Look for a mono amplifier rated 870–1,230 W RMS at the load your coil version wires to. Travel sets the top here, not heat: past 414 W per driver the cone runs beyond Xmax even with the subsonic set, under the driver’s 500 W thermal rating. The top of the range needs the 25 Hz subsonic filter set; without it, keep each driver under 394 W, where the cone reaches Xmax unfiltered. 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 = 52.3–56.9
SEALED 0–50 TRANSITION 50–100 PORTED 100–150 0 50 100 150 Dual 2 Ohm 56.9 Dual 4 Ohm 52.3
Dual 2 Ohm · EBP 56.9Dual 4 Ohm · EBP 52.3
At 52.3–56.9 the VD-12 D2 sits in the transition band, not the sealed band. That is not a mismatch: a transition motor works in either alignment, and sealed buys a smaller box and a gentler roll-off at the cost of some low-end output. Stage 02 shows what this airspace actually does with it.

02What the box does to it

1.000 cu ft against a 43.5 L Vas.

α = Vas ÷ Vb = 1.54  ·  Fc = Fs√(α+1) = 56–59 Hz  ·  Qtc = 0.88–0.96
20 30 50 70 100 150 200 +6 +0 -6 -12 -18 -24 FREQUENCY · Hz LEVEL · dB −3 dB
Dual 2 Ohm · Qtc 0.88, Fc 56 Hz, F3 47.4 HzDual 4 Ohm · Qtc 0.96, Fc 59 Hz, F3 46.9 Hz
The box lifts resonance from 35.3–36.6 Hz free-air to 56–59 Hz and half power lands at 46.9–47.4 Hz, anechoic, before any cabin gain. Figures are Skar Audio’s published parameters; Qes and Qms reproduce the printed Qts. This cabinet holds three drivers in three separate sealed chambers of 1.000 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 11.0 mm, and in this alignment a subsonic filter barely moves it.

PXmax = 394–417 W per driver unfiltered  →  414–425 W with a 25 Hz subsonic
20 30 50 70 100 150 200 0 4 8 12 FREQUENCY · Hz CONE TRAVEL · mm PAST LINEAR TRAVEL · Xmax 11.0 mm 394 W reaches Xmax here
Dual 2 Ohm · 394 W, no filterDual 4 Ohm · 417 W, no filterDual 2 Ohm · 414 W with subsonic at 25 Hz, 24 dB/octDual 4 Ohm · 425 W with subsonic at 25 Hz, 24 dB/octXmax 11.0 mm one-way
Every trace touches the limit and no further, because each is drawn at the exact power that puts that coil on 11.0 mm. Unfiltered that is 394 W per driver, reached first at 33 Hz. It sits under the 500 W the driver can take thermally, so the enclosure sets the ceiling, not the voice coil. The dashed traces are the same driver behind a subsonic filter at 25 Hz, 24 dB/oct, and they sit almost on top of the solid ones: 414 W per driver against 394 W. At 56–59 Hz the filter sits well below resonance, where the sealed alignment has already rolled the cone off at 12 dB/oct, so there is little wasted travel left for it to recover. Set it anyway to keep road rumble out of the cone, but do not size the amplifier around it.
ParamValueUnitNote
Fs35.30 / 36.60Hzfree-air resonance
Qts0.550 / 0.600Dual 2 Ohm / Dual 4 Ohm
Vas43.50 / 44.30Lequivalent compliance
Sd505.3cm²effective piston area
Xmax11mmone-way linear travel
Pe500Wcontinuous RMS
SPL86.7dB1 W / 1 m, derived from T/S

Driver parameters as published by Skar Audio VD-12 D2 / VD-12 D4 published specifications. Curves computed against this enclosure’s actual net airspace.

From the shop floor

Installer's take

Start with the size. 1.000 cubic feet per driver puts the VD-12 at Qtc 0.876, resonance 56.2 Hz, half power 47.4 Hz anechoic. That is Skar Audio's number, not ours: the cabinet is built to the maker's recommended sealed size. Butterworth on these figures wants 2.35, which on this platform means deeper than the 23 in platform allows. It is a small lift near resonance, 0.6 dB above flat. One box serves every coil version: the Dual 2 Ohm at Qtc 0.876, the Dual 4 Ohm at Qtc 0.961.

Measure the base depth, not the top. This cabinet is 15.17 in deep where it meets the floor, 8.98 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.

Impedance. VD-12 D2: wire for 3 ohms (coils in parallel, the three in series), the load most monoblocks are built to deliver full power into; 1.33 ohms is the other clean option (coils in series, the three cups in parallel). VD-12 D4: wire for 2.67 ohms (coils in series, the three cups in parallel), the load most monoblocks are built to deliver full power into; 6 ohms is the other clean option (coils in parallel, the three in series). Work the load out before you buy the amplifier, not after.

Power. Size the amplifier for the set, not one driver: 290 to 410 W RMS per driver is 870 to 1,230 W RMS across all 3. On this driver travel sets the top, not heat: Xmax arrives at 414 W per driver with a 25 Hz subsonic, under the 500 W rating. Set the 25 Hz subsonic to use the top of that range; without it keep each driver under 394 W.

Skar Audio's Qes and Qms reproduce the printed Qts within 3 percent, so the alignment rests on a self-consistent set. Skar Audio do not publish driver displacement; we deduct an estimated 0.085 per driver, so true net can sit a few hundredths either way.

Polyfill is in as a wall lining in every chamber. Do not add more: it makes the box act larger and walks Qtc off 0.88.

Before you order

Questions

Does this fit the Skar Audio VD-12, and its coil versions?

Yes. Each opening is cut to 11.280 in for the 12.6 in frame, and the 4.95 in deep motor clears the raked rear panel with 3.73 in to spare. Both coil versions share the frame, cutout and mounting depth; the alignment table lists each.

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

Why 1.000 cubic feet per driver, and what alignment does it target?

On Skar Audio's published Fs 35.3 Hz, Qts 0.550 and Vas 43.5 liters, 1.000 cubic feet per driver gives Qtc 0.876, system resonance 56.2 Hz and half power 47.4 Hz.

The cabinet is sized to the maker's recommended sealed size, 1.00 cubic feet per driver, to keep it realistic for a cargo floor. Maximally flat would need 2.35 cubic feet per driver; this size trades a little low end for a compact box and a small lift near resonance, 0.6 dB above flat.

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

Skar Audio rates the VD-12 at 500 watts RMS per driver. Recommended amplifier: 290 to 410 W RMS per driver, 870 to 1,230 W RMS for the full set of 3. Travel, not heat, sets the top: the cone reaches Xmax at 414 W per driver with a 25 Hz subsonic set, under the 500 W rating. The top of that range needs the 25 Hz subsonic; without it keep each driver under 394 W.

Each VD-12 D2 has two 2 ohm voice coils, 4 ohms in series or 1 ohm in parallel. With each driver's coils in series and the three cups in parallel, the three present 1.33 ohms to a mono amplifier. With each driver's coils in parallel and the three in series, they present 3 ohms. Three drivers do not reach the round loads a pair does, so check the result against your amplifier's minimum stable impedance before powering up. Each VD-12 D4 has two 4 ohm voice coils, 8 ohms in series or 2 ohms in parallel. With each driver's coils in series and the three cups in parallel, the three present 2.67 ohms to a mono amplifier. With each driver's coils in parallel and the three in series, they present 6 ohms. Three drivers do not reach the round loads a pair does, so check the result against your amplifier's minimum stable impedance before powering up.

Will it fit my SUV?

It is 44 inches wide, 17 tall and 15.17 deep at the base, tapering to 8.98 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 47.4 Hz per driver with system resonance at 56.2 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 1.000 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 Skar Audio VD-12 drivers. The cabinet is cut direct fit to them, not a general purpose 12 inch box.

Same series, same size

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