JL Audio 12W1v3 Dual Box: Sealed 12" Wedge Enclosure Dual 12" Sealed enclosure

The 12W1v3, yes, in both the 2 ohm and the 4 ohm version. The baffle is cut to 11.0625 in, JL's published mounting hole, under the 12.5 in frame. The 5.41 inch motor clears the cabinet with 3.73 inch to spare. Run two of the same coil so the chambers match.

Any other 12, no. The airspace is engineered around the 12W1v3'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.

1.10 cubic feet net per chamber on JL's published figures: the 2 ohm version reads Qtc 0.948 with resonance at 48.3 Hz and half power at 39.0 Hz, and the 4 ohm version reads Qtc 0.934 with resonance at 48.8 Hz and half power at 39.6 Hz. One cabinet serves both versions. The volume is JL's own recommended sealed airspace for the 12W1v3, 1.10 cubic feet per driver, and on JL's published parameters this chamber reproduces JL's printed Qtc, fc and F3 for both versions. That is above maximally flat: punchy, with a clear lift near resonance and extra midbass, the alignment JL itself recommends.

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

JL rates the 12W1v3 at 300 watts RMS per driver, so target 210 to 300 watts RMS per driver at the final load.

JL sells the 12W1v3 as a single voice coil driver in a 2 ohm and a 4 ohm version; a matched pair should share an impedance. A pair of 2 ohm versions lands on 4 ohms in series or 1 ohm in parallel. A pair of 4 ohm versions lands on 2 ohms in parallel or 8 ohms in series. Many amplifiers are not stable at 1 ohm, so on the 2 ohm version series wiring to 4 ohms 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 39.0 Hz on the 2 ohm version and 39.6 Hz on the 4 ohm version 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 1.10 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 39.0 Hz on the 2 ohm version and 39.6 Hz on the 4 ohm version 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 1.10 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, one side-mounted pre-wired terminal cup to both positions, the polyfill lining already in place, and stainless machine screws.

The threaded inserts are already pressed on JL's 11.7 inch bolt circle, so the 12W1v3 drops in and bolts down. The pair of JL Audio 12W1v3 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 12 inch box.