MTX 5512-22 Box: Ported 12" Wedge Enclosure Single 12" Ported enclosure

Sealed, the 5512-22 is listed in our sealed wedge at 1.25 cubic feet, Qtc 1.04, half power 40 Hz. Its Qts is 0.69, high enough that no sealed box of any size reaches a 0.707 alignment, which is why the sealed cabinet is built to MTX's own recommended airspace and prints the Qtc it actually lands on. Vented, the same driver reaches 33.4 Hz. MTX's own vented recommendation for this driver is 1.8 cubic feet net; this cabinet is 1.64 cubic feet tuned to 32.5 Hz through an 18.4 square inch port, sized against the driver's excursion and port speed at full power. The port runs 16.7 m/s in the channel and 10.4 at the mouth at the 400 W design power, and the cone peaks at 6.3 of its 15.24 mm. Passband ripple is 2.5 dB and the in-car spread from 25 to 60 Hz 1.1 dB. Tuning is chosen for in-car response rather than an anechoic curve: a vehicle adds roughly 12 dB per octave below about 45 Hz. In this cabinet that lands at 1.1 dB of in-car spread across 25 to 60 Hz.

The raked face is the seat side. A factory rear seat back leans about 20 degrees off vertical, so the cabinet sits flat against it and uses floor a square box wastes. The baffle stays vertical and fires rearward into the trunk, which acts as the acoustic extension into the cabin. This one is 14.89 inches deep at the base and 9.25 at the top, 30.00 wide and 15.5 tall.

Yes, at 26 Hz, 24 dB per octave. Below tuning a vented box stops loading the cone and excursion runs away toward DC. With the filter in place this cabinet puts the MTX 5512-22 at 41 percent of its usable travel at full rated power; without it there is no meaningful number to quote.

MTX rate the 5512-22 at 400 W RMS and that is the thermal ceiling. The Performance Graphs tab shows the mechanical limit, the power at which the cone reaches the end of its travel in this cabinet: here the cone sits at 41 percent of usable travel at the rating, so heat is what stops you, not travel. A D2 coil is 4 ohms in series or 1 ohm in parallel; run series unless the amplifier is rated for 1 ohm. A D4 is 8 series or 2 parallel.

The two alignments converge at the bottom of the band on this driver rather than crossing cleanly, so there is no meaningful subsonic advantage either way. Above 25 Hz the vent is the louder of the two. The Performance Graphs tab plots this cabinet against the 1.25 cu ft sealed wedge we build for this driver (PO 12-S W MTX 5512-22).

It is a triangular slot in the bottom-rear corner: the floor and the raked back wall are two sides, one bevelled panel is the third. It runs across the cabinet, opens into the box through a 6.46 inch gap at the far end and exits through the side panel as the same triangle. Straight, no bend: 21.79 inches of path and 18.4 square inches of channel running at 16.7 metres per second, 52 percent of its turbulence limit. The three mouth edges are rounded over at 1/2 inch, so the opening at the face is 29.5 square inches and the air leaves it at 10.4 metres per second against the 17.0 threshold where a slot port starts to chuff; the panel's throat end is rounded at 3/8 inch for the same reason. The terminal cup is on the other side.

No, and do not add any. Every sealed Proline X enclosure ships with polyfill; a ported one must not, because damping changes the effective volume the port is tuned against. The port here is cut to 21.79 inches for 32.5 Hz. Stuff it and you move the tuning without shortening the port.

No. This is an enclosure only, cut for the MTX 5512-22 specifically: the 11.188 inch cutout, the 6.250 inch mounting depth allowance and the 1.64 cubic foot alignment all come from MTX's published parameters. This cabinet is built for the 5512-22 specifically, the dual 2 ohm version. MTX gives each coil its own model number and its own published parameters, so the 5512-44 (dual 4 ohm) is a different driver with a different Qts and Vas and takes its own enclosure, not this one. Bring your own driver.