Performance Optimized Wedge Ported 12" Enclosure DD Audio SL612 · Single 12" Ported enclosure

A 0.409 Qts on 68.35 litres of Vas, with a Qes of 0.432 and a Qms of 7.906 behind it, is a big-Vas motor built for a vented box, and 34.5 Hz is where this build lands, with a 35.7 Hz F3. DD publishes no vented alignment of its own for the SL612, so this curve is not weighed against a factory number. The 545.9 square centimetre Sd behind the solve is not a DD figure: DD publishes no Sd for this driver, so it comes from DD's own published piston diameter through Sd = pi times the radius squared. The rear panel carries the wedge's 20 degree rake for the trunk-shaped cabinet; the baffle stays vertical, the port is a triangular chamber run through the side, and the baffle itself is a 1.5 inch double layer. 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 2.5 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 13.52 inches deep at the base and 7.88 at the top, 30.00 wide and 16 tall.

Yes, at 27 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 DD Audio SL612 at 37 percent of its usable travel at full rated power; without it there is no meaningful number to quote.

DD Audio rate the SL612 at 600 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 37 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.

Not one we can show you. We do not build a sealed enclosure for the DD Audio SL612 and DD Audio publish no sealed volume for it, so the Performance Graphs tab carries no ported-versus-sealed chart: the only sealed box left to plot would be this cabinet stuffed and sealed, which nobody would build, and a comparison against it would tell you nothing you could buy. What a vented box gives up is the region below tuning, where the cone unloads and the 27 Hz subsonic filter takes over; around 34.5 Hz the vent carries the load and cone travel drops to its minimum, which no sealed alignment can do.

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 3.21 inch gap at the far end and exits through the side panel as the same triangle. Straight, no bend: 25.04 inches of path and 18.4 square inches of channel running at 21.1 metres per second, 53 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 13.1 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 25.04 inches for 34.5 Hz. Stuff it and you move the tuning without shortening the port.

No. This is an enclosure only, cut for the DD Audio SL612 specifically: the 11.339 inch cutout, the 4.134 inch mounting depth allowance and the 1.30 cubic foot alignment all come from DD Audio's published parameters. It fits both coil versions; the alignment published here is the D2 or D4. Bring your own driver.