AudioControl EPICX8 Dual Box: Sealed 8" Wedge Enclosure Dual 8" Sealed enclosure

The EPICX8, yes, in both coil versions. The baffle is cut to 6.900 in for AudioControl's 8.500 in frame. The 4.10 inch motor clears the cabinet with 0.94 inch to spare. Run two of the same coil so the chambers match.

Any other 8, no. The airspace is engineered around the EPICX8'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.

0.40 cubic feet net per chamber on AudioControl's published figures: the EPICX8 D2 (dual 2 ohm) reads Qtc 0.791 with resonance at 59.4 Hz and half power at 53.7 Hz, and the EPICX8 D4 (dual 4 ohm) reads Qtc 0.782 with resonance at 60.0 Hz and half power at 54.8 Hz. One cabinet serves both coils. That is AudioControl's own recommended sealed size for this driver, 0.4 cubic feet, between their 0.25 minimum and 0.65 maximum. That is a touch above maximally flat: a small lift near resonance and firm midbass.

Cabinet gain in a vehicle lifts the bottom end further, so in the car this reads deeper than the anechoic figures.

AudioControl rates the EPICX8 at 400 watts RMS per driver, so target 280 to 400 watts RMS per driver at the final load.

AudioControl sells the EPICX8 as EPICX8 D2 (dual 2 ohm) and EPICX8 D4 (dual 4 ohm); a matched pair should share a coil. A pair of dual 2 ohm drivers lands on 2 ohms with each woofer's coils in series and the two woofers in parallel, or 8 ohms all in series. A pair of dual 4 ohm drivers lands on 4 ohms with each woofer's coils in series and the woofers in parallel, or 1 ohm with everything in parallel. Anything under 1 ohm, and many amplifiers at 1 ohm, is outside what the amplifier is built for, so 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 drivers fire 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 53.7 Hz on the EPICX8 D2 (dual 2 ohm) and 54.8 Hz on the EPICX8 D4 (dual 4 ohm) on this page.

Two drivers sharing one sealed volume load each other: each driver's compression stroke becomes the pressure the other works against, which blurs the alignment either would have alone. A bonded full-height 3/4 inch divider gives each driver its own 0.40 cubic feet and its own polyfill.

It also means a failure in one driver does not unload the other, and the alignment on this page is the alignment in each chamber, not an average across a shared box.

Anechoic F3 is 53.7 Hz on the EPICX8 D2 (dual 2 ohm) and 54.8 Hz on the EPICX8 D4 (dual 4 ohm) per chamber. Above Qtc 0.707 F3 sits below fc, so the response carries a small lift near resonance before it rolls off.

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 in both chambers 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 0.40 cubic feet per chamber 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 to both positions, the polyfill lining already in place, and a threaded insert kit with stainless machine screws.

The inserts are not pre-installed: AudioControl publishes no bolt circle for the EPICX8, so set the driver in its recess, mark its holes, drill and press the inserts. The pair of AudioControl EPICX8 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 8 inch box.