Performance Optimized Wedge Ported 12" Enclosure | Image Dynamics IDMAX12 V4 Single 12" Ported enclosure

A 26 Hz free-air resonance on 72 litres of Vas is a motor that wants air and a low vent, and 31.5 Hz is where the in-car curve comes out flattest: 1.38 dB of spread across 25 to 60 Hz on 3.63 dB of anechoic ripple. Tuning lower would trade that for a bloated bottom octave once cabin gain is added; tuning higher gives up the reach the 26 Hz motor is paying for. Image Dynamics' own manual puts the IDMAX12 in a 1.75 cubic foot ported box tuned to 35 Hz for its Universal alignment; this cabinet is 1.85 gross, 1.71 net after the driver, vented 3.5 Hz lower for the in-car curve. The channel runs at 17 metres per second to get there, right at our ceiling, and the mouth carries a 1/2 inch roundover on all three edges, so the opening at the face is 31 square inches and the air leaves it at 10.7, well under the 17 where a slot port starts to chuff. 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 1.4 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 16.46 inches deep at the base and 11.00 at the top, 29.00 wide and 15 tall.

Yes, at 25 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 Image Dynamics IDMAX12 V4 at 42 percent of its usable travel at full rated power; without it there is no meaningful number to quote.

Image Dynamics rate the IDMAX12 V4 at 500 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 42 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 IDMAX).

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 3.03 inch gap at the far end and exits through the side panel as the same triangle. Straight, no bend: 24.22 inches of path and 19.9 square inches of channel running at 17.0 metres per second, 47 percent of its turbulence limit. The three mouth edges are rounded over at 1/2 inch, so the opening at the face is 31.4 square inches and the air leaves it at 10.7 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 24.22 inches for 31.5 Hz. Stuff it and you move the tuning without shortening the port.

No. This is an enclosure only, cut for the Image Dynamics IDMAX12 V4 specifically: the 11.024 inch cutout, the 8.071 inch mounting depth allowance and the 1.71 cubic foot alignment all come from Image Dynamics's published parameters. It fits both coil versions; the alignment published here is the D2. Bring your own driver.