Performance Optimized Wedge Sealed 15" Enclosure Skar Audio VXF-15 · Single 15" Sealed enclosure

The VXF-15, yes, in either coil. The baffle is cut to 13.86 in, Skar's published cutout. Skar publishes no outside frame diameter for its 15s, so the flush recess is sized to 15.36 in with margin. The 9.78 inch motor clears the cabinet with 0.75 inch to spare. One cabinet serves both coils: the VXF-15 D2 reads Qtc 0.623 with half power at 62.6 Hz, and the D4 reads Qtc 0.599 at 64.2 Hz.

Any other 15, no. The airspace is worked out from the VXF-15'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.

1.36 cubic feet is the smallest box that carries the VXF-15 frame, already under the Butterworth volume on the D2 figures (Fs 31.4 Hz, Qts 0.36, Vas 76.8 liters): Qtc 0.623, half power at 62.6 Hz. One cabinet serves both coils: the VXF-15 D2 reads Qtc 0.623 with half power at 62.6 Hz, and the D4 reads Qtc 0.599 at 64.2 Hz.

Skar's own recommended sealed volume is 2.75 cubic feet, which reads Qtc 0.51 on the D2 and 0.51 on the D4. Skar's numbers are the only published source for this driver, so treat the Qtc as good to a few hundredths.

Skar rates the VXF-15 at 1500 watts RMS, so target 1050 to 1500 watts RMS at the final load.

The VXF-15 D2 wires to 4 ohms with its coils in series or 1 ohm in parallel. The VXF-15 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 seat-side face carries a 20 degree rake that matches the lean of a factory rear seat back, so the cabinet sits flush against it and the cargo space in front stays usable. The baffle is the vertical trunk-lid-side face, so the driver fires rearward into the trunk cavity.

The trunk acts as an acoustic extension for the sealed box, and the cabin adds real output below 50 Hz, so in-vehicle response runs deeper than the anechoic 62.6 Hz on this page.

The baffle is two bonded 3/4 inch sheets, 1.5 inches through. A single 3/4 inch panel flexes under the pressure a 15 inch woofer puts on it at 1500 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 15.36 inch frame, so the driver bolts to the inner layer and sits flush with the gloss black acrylic insert.

Anechoic F3 is 62.6 Hz on the D2, with system resonance at 54.4 Hz. Below Qtc 0.707 the rolloff is gentle and F3 sits above fc, which is what a damped sealed box does.

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 1.36 cubic feet this cabinet was built to.

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

The inserts ship loose on purpose: Skar prints no bolt circle for the VXF-15, so you set the driver in the recess, mark its holes, drill and press the inserts. The Skar VXF-15 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 15 inch box.