{"product_id":"professional-series-ported-18-enclosure-sundown-audio-x-series-xv4-18-rms","title":"Professional Series Ported 18\" Enclosure | Sundown Audio X-Series XV4 18","description":"\u003cstyle\u003e.df-wrap{font-family:'Helvetica Neue',Arial,sans-serif;line-height:1.75;color:#d6d3d1;max-width:1100px;margin:0 auto;background:#0c0a09}.df-wrap *{box-sizing:border-box}.df-hero{background:linear-gradient(135deg,#0c0a09 0%,#001a91 100%);padding:54px 36px;text-align:center;color:#fff}.df-hero h2{font-size:2.3em;font-weight:800;text-transform:uppercase;letter-spacing:1.5px;margin:0 0 12px;color:#fff}.df-hero p{font-size:1.1em;font-weight:300;opacity:.93;margin:0 0 22px;color:#d6d3d1}.df-badges{display:flex;justify-content:center;flex-wrap:wrap;gap:10px}.df-badge{background:rgba(91,120,255,.18);border:1px solid #5b78ff;color:#99abff;padding:7px 16px;border-radius:18px;font-size:.8em;font-weight:600}.df-stats{display:flex;flex-wrap:wrap;background:#1c1917}.df-stat{flex:1 1 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class=\"df-wrap\"\u003e\n\n\u003cdiv class=\"df-hero\"\u003e\n  \u003ch2\u003eProline X Professional 18\" Ported\u003c\/h2\u003e\n  \u003cp\u003eA ported eighteen-inch box built to Sundown's own numbers for the X-Series XV4 18\u003c\/p\u003e\n  \u003cdiv class=\"df-badges\"\u003e\n    \u003cspan class=\"df-badge\"\u003e5.99 cu ft net\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eTuned 32.0 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eF3 25.8 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003e2.25\" three-layer baffle\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eCut for the X-Series XV4 18\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eBuilt in Tennessee\u003c\/span\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-stats\"\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e5.99\u003c\/span\u003e\u003cspan class=\"l\"\u003ecu ft net\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e32.0\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz tuning\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e25.8\u003c\/span\u003e\u003cspan class=\"l\"\u003eHz F3 anechoic\u003c\/span\u003e\n\u003c\/div\u003e\n  \u003cdiv class=\"df-stat\"\u003e\n\u003cspan class=\"n\"\u003e112.1\u003c\/span\u003e\u003cspan class=\"l\"\u003esq in port area\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhy this driver is vented at 32.0 Hz\u003c\/h3\u003e\n  \u003cp\u003eThe Sundown Audio X-Series XV4 18 D1 carries an 18.42 inch frame and a 15.00 inch mounting depth, and this cabinet gives it 5.993 cubic feet net, vented at 32.0 Hz through a 112.1 square inch port beside the woofer on the front face. F3 lands at 25.8 Hz with 5.57 dB of passband ripple. The 36.0 by 21.0 by 26.0 inch enclosure carries a single 90 degree bend in the port, and the D2 version of this driver shares the same cabinet.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThreaded insert kit ships with this box.\u003c\/strong\u003e Sundown Audio does not publish the mounting hole locations for the X-Series XV4 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.\u003c\/p\u003e\n  \u003cp\u003eSundown publishes a Qts of 0.540 for the X-Series XV4 18 D1, and the figure checks out against their own Qes of 0.630 and Qms of 4.130. Sundown does not recommend this driver sealed; their own ported figure is 7.00 cubic feet at 32 Hz through a 112 square inch port. Their 7.00 cubic feet does not fit the Professional envelope with a port that stays quiet at the coil's rated power, 2750 W: the largest slot that fits that airspace runs well over 17 metres per second. This cabinet keeps Sundown's tuning and their 112 square inch port in the largest airspace that does fit, 5.99 cubic feet at 32.0 Hz. The port stays clean to 3836 W before mouth velocity becomes the limiting factor, the cone peaks at 12.4 of its 30.0 mm at rated power, and ripple across the passband holds at 5.57 dB.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eWhat makes it Professional\u003c\/h3\u003e\n  \u003cdiv class=\"df-grid\"\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThree-layer baffle, flush mount\u003c\/h4\u003e\n\u003cp\u003eThree layers of 3\/4 inch Langboard Elite make a 2.25 inch\n    front. The outer layer is routed to the flange, so the woofer sits flush with the face; the two layers behind it\n    carry the mounting hardware and the load.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eSundown Audio logo acrylic\u003c\/h4\u003e\n\u003cp\u003eA glossy black acrylic insert with the Sundown Audio mark sits in the outer\n    layer beside the woofer. It is standard on every Professional cabinet.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eThreaded insert kit ships with this box\u003c\/h4\u003e\n\u003cp\u003eThreaded insert kit included, inserts NOT pre-installed: the manufacturer publishes no mounting hole locations, so the kit ships with the box for installation when the woofer goes in: 8 to 12 inserts sized to the woofer, the correct drill bit, 2.5 inch allen-head screws, allen key and gasket tape.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003ePort gated at 2750 W\u003c\/h4\u003e\n\u003cp\u003eThe 112.1 square inch slot beside the woofer is sized so the\n    channel runs 17.8 metres per second and the mouth 14.4 metres per second at the driver's rated power, under the\n    17 metres per second where a slot starts to chuff. The channel runs 16.50 inches along its wall and turns once along the back wall for another 8.41 inches, which is why a 32.0 Hz tuning fits a 26.00 inch deep box.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhy this is a Professional build\u003c\/h4\u003e\n\u003cp\u003eEvery 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 X-Series XV4 18 does not fit that envelope at all: no tuning, width or depth inside it carries a 15.00 inch deep 18 inch driver at 2750 W. This box is the chassis with the width, depth and port to carry it.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhat the price covers\u003c\/h4\u003e\n\u003cp\u003eThis cabinet is 11.38 cubic feet outside. At 104 lb it ships freight; delivery to the 48 states is inside the price and checkout adds nothing.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhat Sundown Audio recommend\u003c\/h4\u003e\n\u003cp\u003eSundown Audio publish a vented box for the X-Series XV4 18 at 7.00 cubic feet on a basis they do not state, tuned to 32.0 Hz. This cabinet holds 5.99 cubic feet net and tunes to 32.0 Hz. They call for a port area of 112 sq in. The chassis envelope sets the volume here, and the port is sized so the mouth stays under the chuff threshold at the design power rather than to reach their figure.\u003c\/p\u003e\n\u003c\/div\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe cabinet\u003c\/h3\u003e\n  \u003cp\u003e36.00\" W x 21.00\" H x 26.00\" D external. Two windowed braces run front to back either side of the woofer, clearing the cutout by two and a half inches. The box ships dry: polyfill detunes a ported alignment. This is our single-eighteen ported envelope built around the X-Series XV4 18's own frame and motor depth. At this size it ships freight, and the freight is in the price.\u003c\/p\u003e\n  \u003cp\u003eFrame, cutout and mounting depth are Sundown's own published dimensions, and the Qts figure agrees with what its own Qes and Qms predict. Sundown prints the cone area as the nominal disc, so the 1134 square centimetre figure behind this alignment is derived from their Vas and Cms instead. They list 30 mm of Xmax without stating how it was measured, and at rated power the cone uses 12.4 mm of it. The slot mouth runs 14.4 metres per second at 2750 W against the 17 metre per second point where a slot starts to chuff. The page's D2 column does not hold together (a Qts of 0.84 against the 0.48 its own Qes and Qms give, and 17.6 litres of Vas against the D1's 93.7), so this cabinet is solved on the D1 column; the D2 coil shares the same basket and fits the same cabinet. Sundown's page carries two power figures, 3000 W in the title and 2750 W in the spec table; this cabinet is designed against the lower one, which their notice on revised ratings makes the current figure. Sundown Audio does not publish the mounting hole locations for the X-Series XV4 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.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"df-section\"\u003e\n  \u003ch3\u003eThe numbers to respect\u003c\/h3\u003e\n  \n  \u003cp\u003eSet a 25 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in\n  place the cone reaches 12.4 mm of its 30.0 mm at 2750 W.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":44853127315545,"sku":"Pro 18-P XV418","price":1399.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0689\/1389\/files\/Pro_18-P_XV418_Front_d5e54d63-8bf5-4878-9aef-c90918bb8ac8.jpg?v=1794018318","url":"https:\/\/audiointensity.com\/products\/professional-series-ported-18-enclosure-sundown-audio-x-series-xv4-18-rms","provider":"Audio Intensity","version":"1.0","type":"link"}