Performance Optimized Wedge Sealed 12" Enclosure | Image Dynamics IDQ 12 Single 12" Sealed enclosure

Installer's take

INSTALLER'S TAKE Trunk-load wedges are one of the oldest tricks in the SQ playbook, and they still work as well as they ever did. The idea is simple: mount the woofer on the vertical face that faces the trunk lid, angle the opposite face to match the lean of the rear seat back, and let the trunk cavity load the driver. Done right, you get smoother low-end integration into the cabin, a system that doesn't localize behind the listener, and a cabinet that tucks into the trunk shelf area without stealing usable cargo space. For the IDQ12 V4 specifically, the wedge geometry solves a real problem. The IDQ12 wants 1.0 to 1.4 cubic feet sealed to hit its SQ-oriented Qtc target and deliver its published low-end extension. That's a big box. In most trunks, a rectangular 1.4 cubic foot cabinet occupies enough floor space to make the trunk essentially useless for anything else. The wedge tucks against the seat back where cargo can't fit anyway, and leaves the trunk floor space in front of the wedge actually useable. The 8.75 inch top to 14.2 inch bottom depth difference on the seat-side face creates a 20 degree lean back from vertical, the same angle as most factory rear seat backrests within a couple degrees. When you push the wedge back against the rear seat, the angled seat-side face sits flush against the seat back with no wasted gap. The vertical trunk-lid-side face is where the woofer mounts, firing rearward toward the trunk lid. Why fire the woofer rearward instead of into the cabin? Two reasons. First, it uses the trunk cavity as an acoustic loading chamber, the trunk itself becomes part of the low-frequency reproduction path. Bass energy transmits into the passenger cabin through the rear deck, seat back, and side boundaries rather than firing directly at the listener. The result is a smoother, less localized bass presentation. Second, it lets the wedge sit against the seat without any air path or firing obstruction on the front side of the box. If you tried to fire the woofer forward through the seat back, you'd need clearance in front of the driver, and the whole point of the wedge shape is that you don't have that clearance. The 1.4 cubic foot gross volume works out to about 1.3 cubic feet net after the IDQ12's 0.1 cubic foot displacement. That sits between ID's compact and audiophile spec ranges, in the sweet spot for a driver you actually want to listen to. Compact volumes tighten the driver and dry out the presentation. Audiophile volumes loosen it up. 1.3 net is the balanced middle where the IDQ delivers what people bought it for. Wiring is standard IDQ12. Dual 2 ohm gets you 1 ohm parallel or 4 ohms series. Dual 4 ohm gets you 2 ohms parallel or 8 ohms series. 300 to 400 watts RMS at your chosen impedance is the target. The IDQ is a driver that rewards a clean amp, regulated power supply, honest RMS ratings, low THD. Don't cheap out on the amplifier if you're spending money on the driver. If your trunk shape has been fighting you and you've been considering a smaller box just to make it fit, this is the answer. Full-size IDQ12 airspace, trunk-friendly wedge geometry that fires cleanly into the trunk cavity, driver-specific engineering. -Scott