Professional Series Ported 18" Enclosure | Ampere Audio AA-2.75 18

Sealed, the AA-2.75 18 builds well: our wedge holds 2.15 cubic feet at Qtc 0.63 to 0.66 with half power at 56 to 57 Hz. Vented, the same driver reaches 31.1 Hz. The port runs 15.7 m/s in the channel and 11.2 at the mouth at 1200 W, 1.2 times Ampere's rating, and the cone peaks at 6.0 of its 19 mm. Passband ripple is 0.3 dB and the in-car spread from 25 to 60 Hz 3.4 dB. 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 AA-2.75 18 does not fit that envelope at all: no tuning, width or depth inside it carries a 10.12 inch deep 18 inch driver at 1000 W. This box is the chassis with the width, depth and port to carry it. 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, an Ampere Audio logo acrylic, and a port and excursion budget checked at 1200 W. It carries a 2 year warranty, against 1 year on the Performance Optimized lines.

Ampere Audio does not publish the mounting hole locations for the AA-2.75 18, 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 Ampere Audio AA-2.75 18 at 31 percent of its usable travel at 1200 W.

Not one we can show you. We do not build a sealed enclosure for the Ampere Audio AA-2.75 18 and Ampere 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 26 Hz subsonic filter takes over; around 32.5 Hz the vent carries the load and cone travel drops to its minimum, which no sealed alignment can do.

It is a vertical slot beside the woofer, the full height of the cavity, 3.00 inches wide and 58.5 square inches. It runs 9.25 inches to the back wall and turns once along it for 16.34 inches; the fold costs about 1.5 Hz and the port is cut for it. The channel runs at 15.7 metres per second at 1200 W, 28 percent of its turbulence limit, and the mouth edges carry a 1/2 inch roundover so the air leaves the face at 11.2 metres per second against the 17 metres per second threshold where a slot starts to chuff.

76 lb, 36.00" W x 21.00" H x 16.00" D external. Every Professional cabinet is priced the same way, by its size: this one is 7.00 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 76 lb parcel and checkout adds nothing. Do not add polyfill; it ships dry on purpose.

No. This is an enclosure only, cut for the Ampere Audio AA-2.75 18 specifically: the 16.690 inch cutout, the 10.125 inch mounting depth allowance and the 3.41 cubic foot alignment all come from Ampere Audio's published parameters. It fits both coil versions (D2 and D4), and the cabinet was checked against both. Bring your own driver.