Performance Optimized Down Fire Wide Sealed Dual 12" Enclosure Focal SUB 30 KXE · Dual 12" Sealed enclosure

Because some installs run out of height or depth before they run out of length. The standard Focal SUB 30 KXE Down Fire cabinet is 30 by 15 by 11.73 inches; this one is 41 by 14 by 9.5625. Spreading the airspace along 11 more inches lets the cabinet stand 2.1675 inches lower, and at 14 inches deep it is 1 inch shallower front to back, about the minimum a 12 inch frame needs.

If you have 41 inches of run and height or depth is the limit, this is the shape. If length is the limit, the standard 30 x 15 is the better fit.

Same driver, same construction, different shape. The standard box is 30 by 15 by 11.73 inches and holds 0.85 cubic feet net per chamber; this one is 41 by 14 by 9.5625 inches and holds 0.858 cubic feet net per chamber.

The airspace is matched, so the alignment is effectively the same. The choice is about the shape of your space: the standard box when length is limited, this one when height or depth is the limit and you have 41 inches of run.

Focal rates the SUB 30 KXE at 800 watts RMS per driver and 1600 watts maximum, so target 560 to 800 watts RMS per driver at the final load.

Each SUB 30 KXE carries two 4 ohm voice coils (3.2 ohms DC each): series for 8 ohms, parallel for 2. Wire both drivers identically. Each driver in series with the pair in parallel gives 4 ohms, the safe load on any amplifier; each driver in parallel with the pair in series also gives 4; all four coils in parallel is 1 ohm and needs an amplifier rated for it; all in series is 16 ohms. Confirm your amplifier's minimum stable impedance first.

The cabinet is 9.5625 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 11.3125 inches.

The footprint is 41 inches wide by 14 deep, the Down Fire Wide platform. 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 SUB 30 KXE its own 0.858 cubic feet and its own polyfill.

It also means the alignment on this page is the alignment in each chamber, not an average across a shared box, and the divider ties the walls together across the 41 inch span.

Anechoic per chamber, : F3 45.3 Hz with system resonance at 50.7 Hz (Qtc 0.804). Above Qtc 0.707 the response rises slightly ahead of the rolloff, so F3 sits below fc.

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 0.858 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 terminal cup pre-wired 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: Focal prints no bolt circle for the SUB 30 KXE, so you set each driver in its recess, mark its holes, drill and press the inserts. The pair of Focal SUB 30 KXE is purchased separately.