Performance Optimized Down Fire Sealed Dual 12" Enclosure Ground Zero GZRW 300-D2 FLAT · Dual 12" Sealed enclosure

The GZRW 300-D2 FLAT, yes, in the dual 2 ohm version. The baffle is cut to 10.94 in, Ground Zero's published cutout, under the 12.72 in frame. The 3.66 inch motor clears the cabinet with 11.25 inch to spare. Run two of the same coil so the chambers match.

Any other 12, no. The airspace is engineered around the GZRW 300-D2 FLAT'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.

1.34 cubic feet net per chamber on Ground Zero's published figures: the dual 2 ohm reads Qtc 0.707 with resonance at 37.8 Hz and half power at 37.8 Hz. Ground Zero publishes no sealed volume for the GZRW 300-D2 FLAT, so the cabinet is solved to the maximally flat alignment, Qtc 0.707. That is maximally flat, the reference sealed alignment.

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

Ground Zero rates the GZRW 300-D2 FLAT at 450 watts RMS per driver, so target 315 to 450 watts RMS per driver at the final load.

Ground Zero sells the GZRW 300-D2 FLAT as dual 2 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. 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 cabinet is 15.66 inches tall measured in the down fire position, and that figure excludes the standoffs. The standoffs hold 1.75 inches under the baffle, so plan your space around a finished stack of roughly 17.41 inches.

The footprint is the standard Performance Optimized down fire platform, 30.00 inches wide by 15.00 deep. Height is the only dimension solved to the driver.

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 1.34 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 37.8 Hz per chamber. The lower-Q coil rolls off gently with F3 above fc; the higher-Q coil carries a small lift near resonance.

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 1.34 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, the standoffs, and a threaded insert kit with stainless machine screws.

The inserts ship loose on purpose: Ground Zero prints no bolt circle for the GZRW 300-D2 FLAT, so you set the driver in the recess, mark its holes, drill and press the inserts. The pair of Ground Zero GZRW 300-D2 FLAT is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 12 inch box.