AudioControl Spike SPK-12 Box: Sealed 12" Down Fire Enclosure Single 12" Sealed enclosure

The Spike SPK-12, yes, in both coil versions. The baffle is cut to 11.125 in for AudioControl's 12.760 in frame. The 6.14 inch motor clears the cabinet with 0.75 inch to spare.

Any other 12, no. The airspace is engineered around the Spike SPK-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.

1.06 cubic feet net on AudioControl's published figures: the SPK-12S2 (single 2 ohm) reads Qtc 0.915 with resonance at 50.9 Hz and half power at 41.8 Hz, and the SPK-12S4 (single 4 ohm) reads Qtc 1.009 with resonance at 55.9 Hz and half power at 43.8 Hz. One cabinet serves both coils. AudioControl recommends 1 cubic feet for this driver; the 6.14 inch motor sets the minimum height of this down fire, which holds more. That is well above maximally flat: a clear lift near resonance and extra midbass, the way AudioControl voices it in this size.

The 6.14 inch mounting depth sets the minimum cabinet height here, so the airspace is what the motor allows rather than a free choice.

AudioControl rates the Spike SPK-12 at 500 watts RMS, so target 350 to 500 watts RMS at the final load.

AudioControl sells the SPK-12 as SPK-12S2 (single 2 ohm) and SPK-12S4 (single 4 ohm): the SPK-12S2 (single 2 ohm) is a single 2 ohm coil, a 2 ohm load; the SPK-12S4 (single 4 ohm) is a single 4 ohm coil, a 4 ohm load. A parallel load at or under 1 ohm needs an amplifier rated for it. Confirm your amplifier's minimum stable impedance first.

The cabinet is 7.64 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 9.39 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, and here it is the Spike SPK-12's 6.14 inch motor that sets it.

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 500 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 AudioControl's 12.760 inch frame, so the driver bolts to the inner layer.

Anechoic F3 is 41.8 Hz on the SPK-12S2 (single 2 ohm) and 43.8 Hz on the SPK-12S4 (single 4 ohm). 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 1.06 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, the standoffs, and a threaded insert kit with stainless machine screws.

The inserts are not pre-installed: AudioControl publishes no bolt circle for the SPK-12, so set the driver in its recess, mark its holes, drill and press the inserts. The AudioControl Spike SPK-12 is purchased separately, and the cabinet is cut direct fit to it, not a general purpose 12 inch box.