Performance Optimized Down Fire Sealed 12" Enclosure Skar Audio VD-12 · Single 12" Sealed enclosure

The VD-12 D2 or D4, yes. The baffle is cut to 11.28 in, Skar's published cutout, under the 12.60 in frame. The 4.95 inch motor clears the cabinet with 1.64 inch to spare. The VD-12 D4 fits the same cut; on Skar's published D4 set (Fs 36.6 Hz, Qts 0.60, Vas 44.3 liters) it lands at Qtc 0.961 with half power at 46.9 Hz, a livelier alignment than the D2.

Any other 12, no. The airspace is worked out from the VD-12's own Qts and Vas, and a different woofer that happened to drop into the hole would not see the alignment printed on this page.

1.00 cubic feet is the volume this cabinet is built to on the D2 figures (Fs 35.3 Hz, Qts 0.55, Vas 43.5 liters): Qtc 0.876, half power at 47.4 Hz. The VD-12 D4 fits the same cut; on Skar's published D4 set (Fs 36.6 Hz, Qts 0.60, Vas 44.3 liters) it lands at Qtc 0.961 with half power at 46.9 Hz, a livelier alignment than the D2.

That is Skar's own recommended sealed volume for the VD-12. It reads Qtc 0.88 on the D2 and 0.96 on the D4, above the 0.707 of a maximally flat alignment, so expect a mild lift near 56 Hz (59 Hz on the D4) rather than a flat rolloff. Skar's numbers are the only published source for this driver, so treat the Qtc as good to a few hundredths.

Skar rates the VD-12 at 500 watts RMS, so target 350 to 500 watts RMS at the final load.

The VD-12 D2 wires to 4 ohms with its coils in series or 1 ohm in parallel. The VD-12 D4 wires to 8 ohms in series or 2 ohms in parallel. Anything under 1 ohm, and many amplifiers at 1 ohm, is outside what the amplifier is built for; series wiring is the safe default. Confirm your amplifier's minimum stable impedance first.

The cabinet is 7.34 inches tall measured in the down fire position, and that figure excludes the standoffs. The standoffs hold 1.75 inches under the baffle, so plan your space around a finished stack of roughly 9.09 inches.

The footprint is the standard Performance Optimized down fire platform, 30.00 inches wide by 15.00 deep. Height is the only dimension solved to the driver.

The baffle is two bonded 3/4 inch sheets, 1.5 inches through. A single 3/4 inch panel flexes under the pressure a 12 inch woofer puts on it at 500 watts, which smears output and works the driver loose over time; the second layer stiffens the face and gives the mounting hardware twice the material to bite.

The outer layer is machined as a flush recess to the 12.60 inch frame, so the driver bolts to the inner layer.

Anechoic F3 is 47.4 Hz on the D2, with system resonance at 56.2 Hz, and 46.9 Hz on the D4, with resonance at 58.6 Hz. Above Qtc 0.707 the response carries a small bump before the rolloff and F3 sits below fc.

Those figures exclude cabin gain. In a car the cabin's transfer function adds real output below 50 Hz, so in-vehicle response runs deeper than the numbers above.

No. Polyfill is already installed as a light wall lining to control internal reflections, and the quantity is chosen so it does not change the acoustic volume.

Do not add more. Packing a sealed box with fill makes it behave as though it were larger, which walks the alignment away from the 1.00 cubic feet this cabinet was built to.

No driver. This is an enclosure only. You receive the cabinet finished in plush black carpet, one side-mounted pre-wired terminal cup, the polyfill lining already in place, the standoffs, and a threaded insert kit with stainless machine screws.

The inserts ship loose on purpose: Skar prints no bolt circle for the VD-12, so you set the driver in the recess, mark its holes, drill and press the inserts. The Skar VD-12 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 12 inch box.