Performance Optimized Wedge Wide Sealed Dual 12" Enclosure Arc Audio ARC 12 · Dual 12" Sealed enclosure

Yes, both coils: they share the 12.375 in frame, the 11 in cutout and the 6 in mounting depth, and the motor clears the cabinet with 2.82 in to spare. One cabinet serves both coils: the ARC 12 D2 reads Qtc 0.707 with half power at 38.8 Hz, and the D4 reads Qtc 0.802 at 35.6 Hz. Run two of the same coil so the chambers match.

Any other 12, no. The airspace is worked out from the ARC 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.

1.39 cubic feet is the Butterworth volume for the ARC 12 D2. On the D2 figures (Fs 22.8 Hz, Qts 0.42, Vas 74.4 liters) that is Qtc 0.707 with half power at 38.8 Hz. At Qtc 0.71 the response is maximally flat into the rolloff, so F3 and fc coincide.

The face is fixed at 41 by 16 for the whole wide dual line, so depth is the only free dimension. One cabinet serves both coils: the ARC 12 D2 reads Qtc 0.707 with half power at 38.8 Hz, and the D4 reads Qtc 0.802 at 35.6 Hz.

The ARC 12 is rated at 350 watts RMS per driver, so target 244 to 350 watts RMS per driver at the final load.

A pair of ARC 12 D2 drivers can land on 0.5 ohm with all four coils in parallel, 2 ohms as series pairs in parallel, or 8 ohms all in series. A pair of ARC 12 D4 drivers can land on 1 ohm with all four coils in parallel, 4 ohms as series pairs in parallel, or 16 ohms all in series. 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.

41 inches across lets two 12 inch drivers sit side by side while the cabinet stays 15.14 inches deep at the base, so it spans a cargo floor instead of eating into it. The back panel rakes 20 degrees to sit flush against the rear seat.

The cargo area 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 38.8 Hz 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 1.39 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 38.8 Hz per chamber on the D2 and 35.6 Hz on the D4. At Qtc 0.71 the response is maximally flat into the rolloff, so F3 and fc coincide.

Those figures exclude cabin gain. In a vehicle 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 1.39 cubic feet per chamber this cabinet was built to.

No drivers. 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 ship loose on purpose: Arc Audio prints no bolt circle for the ARC 12, so you set each driver in its recess, mark its holes, drill and press the inserts. The pair of Arc Audio ARC 12 is purchased separately.