Professional Series Ported 12" Enclosure Sundown Audio U-Series v.1 12 · Single 12" Ported enclosure

At the coil's rated power of 1500 W the port on this box is nowhere near the chuff line; it stays clean all the way to 1652 W before the mouth velocity crosses it, so the coil's own rating is the limit here, not the port. Sundown publish a Qts of 0.34 for the D4 coil, with the Qes and Qms behind it in agreement, describing a driver that is moderately damped rather than built purely for excursion. Passband ripple holds at 3.86 dB across the tuning, a shallow rise that stays close to flat through the passband. Tuning is chosen for in-car response rather than an anechoic curve: a vehicle adds roughly 12 dB per octave below about 45 Hz, and this tuning is where that sum comes out flattest across 25 to 60 Hz.

Every driver is run through the Performance Optimized wedge and down-fire before this chassis; the Professional box is where a driver lands when that smaller envelope, 30 inches wide and 18 inches deep with a triangular side port, cannot give it what it needs at its rated power. The U-Series v.1 12 did not clear the port gate there. The calmest wedge port that fits that envelope is 24.7 square inches at 30.0 by 11.00 by 16.64 inches, and its mouth runs 22.7 metres per second at 1500 W against the 17 metres per second line where a port starts to chuff. That port would stay clean to about 839 W. The slot on this box reaches 36.2 square inches and holds the mouth at 16.2 metres per second at 1500 W. An under-ported box does not fail quietly. Air speed at the mouth rises with power; past the chuff line the flow turns turbulent and the port is audible on every note. The turbulence also chokes the port, so the box behaves as if it were tuned higher than it is, loses output near tuning, and lets the cone travel further below tuning than the design allows. This chassis is a full-size front-firing box on a 2.25 inch baffle built from three 3/4 inch layers with the woofer flush-mounted in the outer layer, a Sundown Audio logo acrylic, and a port and excursion budget checked at 1500 W. It carries a 2 year warranty against 1.

Sundown Audio does not publish the mounting hole locations for the U-Series v.1 12, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, an allen key and woofer gasket tape. You set the inserts when you mount the woofer; one kit serves one woofer. A dual cabinet ships two kits.

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 Sundown Audio U-Series v.1 12 at 36 percent of its usable travel at 1500 W.

Below about 24 Hz, yes. The maker's recommended sealed box is louder down there by up to 5.2 dB, because a sealed box rolls off gently into the subsonic region where a vented one falls away steeply once it is under tuning. Above that this alignment is the louder of the two for the same power. The Performance Graphs tab plots this cabinet, 1.84 cubic feet vented at 34.5 Hz, against Sundown Audio's recommended sealed box, 1.00 cu ft, so you can see exactly where they cross.

It is a vertical slot beside the woofer, the full height of the cavity, 2.50 inches wide and 36.2 square inches. It runs 8.25 inches to the back wall and turns once along it for 20.30 inches; the fold costs about 1.5 Hz and the port is cut for it. The channel runs at 24.2 metres per second at 1500 W, 49 percent of its turbulence limit, and the mouth edges carry a 1/2 inch roundover so the air leaves the face at 16.2 metres per second against the 17 metres per second threshold where a slot starts to chuff.

59 lb, 32.00" W x 16.00" H x 14.50" D external. It ships as a UPS parcel; the price includes shipping in the 48 states. Every Professional cabinet is priced the same way, by its size: this one is 4.30 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 59 lb parcel and checkout adds nothing. Do not add polyfill; it ships dry on purpose.

No. This is an enclosure only, cut for the Sundown Audio U-Series v.1 12 specifically: the 11.010 inch cutout, the 7.750 inch mounting depth allowance and the 1.84 cubic foot alignment all come from Sundown Audio's published parameters. It fits both coil versions; the alignment published here is the D4. Bring your own driver.