Performance Optimized Wedge Sealed Dual 12" Enclosure | Alpine S2-W12

Yes. Both coil versions share the same frame, the same 10.75 in mounting hole and the same 4.88 in mounting depth, so the baffle is cut once and fits either.

They also land within a few thousandths of each other acoustically in this cabinet: Qtc 0.780 on the S2-W12D2 and Qtc 0.780 on the S2-W12D4. The choice between them is an impedance decision, not an enclosure one.

Because Alpine did. They publish 0.85 cubic feet as the ideal sealed volume for this driver, inside a recommended range of 0.61 to 1.06 cubic feet. This cabinet is built to the middle of that range rather than to a number we chose.

Each chamber is 0.91 cubic feet gross. Subtract the driver's 0.06 cubic feet of displacement and you are left with the 0.85 net Alpine asks for.

The Alpine S2-W12 is rated 600 watts RMS each, so target 1200 watts RMS total at whatever impedance you wire to.

Watch the load. Four coils in parallel gives 1 ohm, which many amplifiers are not stable into. 4 ohms is the sensible target on a pair. Set gains by ear or with an oscilloscope rather than to a number, and remember a sealed box of this size will take clean power far better than clipped power.

The angled seat-side face matches the roughly 20 degree lean of a factory rear seat, so the cabinet sits flat against it instead of leaving a wasted triangle. The vertical trunk-lid-side face carries the driver, firing rearward into the trunk cavity.

Firing rearward means the output loads into the trunk volume and reaches the cabin through the rear seat and deck rather than beaming at the back of your head, which makes it easier to keep the stage forward. The taper also gives height back where the lid closes, so you keep usable cargo space.

The baffle is two bonded 3/4 inch MDF sheets, 1.5 inches through. A subwoofer pushes as hard against its mounting surface as it does against the air, and a single 3/4 inch panel flexes under that load, which smears output and loosens the driver over time.

1.5 inches also gives the threaded inserts real material to hold in, so the driver bolts down to metal rather than into MDF and can come back out as many times as the install takes.

Anechoic F3 lands at 44.2 to 46.7 Hz depending on coil, at Qtc 0.780. That is a musical alignment with a little lift at resonance rather than a maximally flat one.

That figure is anechoic and does not include cabin gain. In a car the transfer function of the cabin adds meaningful output below 50 Hz, so in-vehicle response runs deeper than the number above. Build for the alignment, then let the cabin do the rest.

No. Polyfill is already installed as a light wall lining to control internal reflections, and the amount 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 would move the alignment off the 0.85 cubic feet Alpine specifies and undo the reason this cabinet is the size it is.

No. This is an enclosure only. You receive the cabinet finished in plush black carpet, with threaded inserts installed at both driver positions, stainless machine screws, one side-mounted pre-wired terminal cup and the polyfill lining already in place.

The Alpine S2-W12 drivers are purchased separately. The cabinet is cut direct fit to that driver, so it is not a general purpose 12 inch box.