JL Audio 12W1v3 Box: Sealed 12" Wedge Enclosure Single 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 0.75 inch to spare.

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 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, so target 210 to 300 watts RMS at the final load.

JL sells the 12W1v3 as a single voice coil driver in a 2 ohm and a 4 ohm version: the 2 ohm version presents 2 ohms; the 4 ohm version presents 4 ohms, wired straight to the terminal cup. 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 39.0 Hz on the 2 ohm version and 39.6 Hz on the 4 ohm version 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 12 inch woofer puts on it at 300 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 JL's 12.5 inch frame, so the driver bolts to the inner layer and sits flush with the gloss black acrylic insert.

Anechoic F3 is 39.0 Hz on the 2 ohm version and 39.6 Hz on the 4 ohm version. 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 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 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, 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 JL Audio 12W1v3 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 12 inch box.