Professional Series Ported 8" Enclosure | Sundown Audio M-Series M8

Sundown publishes a Qts of 0.418 for the M8 D2, and the figure checks out: computing it from their own Qes of 0.473 and Qms of 3.589 lands within a rounding error of the published number. The gate here is measured at the coil's rated power, 800 W, and the port stays clean past that rating, modeled to 1456 W before mouth velocity becomes the limiting factor rather than the coil. Ripple across the passband holds at 5.2 dB, the tradeoff of fitting a full alignment into an eight-inch box this size. 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 M-Series M8 did not clear the port gate there. The calmest wedge port that fits that envelope is 13.0 square inches at 30.0 by 10.50 by 14.78 inches, and its mouth runs 19.6 metres per second at 800 W against the 17 metres per second line where a port starts to chuff. That port would stay clean to about 604 W. The slot on this box reaches 28.1 square inches and holds the mouth at 10.7 metres per second at 800 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 800 W. It carries a 2 year warranty, against 1 year on the Performance Optimized lines.

Sundown Audio does not publish the mounting hole locations for the M-Series M8, so we cannot install the threaded inserts before it ships. The threaded insert kit comes in the box instead: 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, and this box ships with one kit.

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 Sundown Audio M-Series M8 at 49 percent of its usable travel at 800 W.

Below about 22 Hz, yes. The maker's recommended sealed box is louder down there by up to 2.9 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, 1.28 cubic feet vented at 33.0 Hz, against Sundown Audio's recommended range (low end) sealed box, 0.25 cu ft, so you can see exactly where they cross.

It is a vertical slot beside the woofer, the full height of the cavity, 2.25 inches wide and 28.1 square inches. It runs 10.00 inches to the back wall, 18.25 across it and 2.83 forward along the far side; the two folds cost about 3.0 Hz and the port is cut for it. The channel runs at 16.7 metres per second at 800 W, 39 percent of its turbulence limit, and the mouth edges carry a 1/2 inch roundover so the air leaves the face at 10.7 metres per second against the 17 metres per second threshold where a slot starts to chuff.

51 lb, 26.00" W x 14.00" H x 16.00" D external. Every Professional cabinet is priced the same way, by its size: this one is 3.37 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 51 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 M-Series M8 specifically: the 7.320 inch cutout, the 6.330 inch mounting depth allowance and the 1.28 cubic foot alignment all come from Sundown Audio's published parameters. It fits both coil versions; the alignment published here is the D2. Bring your own driver.