{"product_id":"professional-series-ported-18-enclosure-dayton-audio-ultimax-ii-umii18","title":"Dayton Audio Ultimax II UMII18 Box: Ported 18\" Professional Series Enclosure","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\u003eOne Ultimax II UMII18 in a front-firing Professional box, vented at 27.0 Hz on a three-layer flush-mount baffle\u003c\/p\u003e\n  \u003cdiv class=\"df-badges\"\u003e\n    \u003cspan class=\"df-badge\"\u003e3.40 cu ft net\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eTuned 27.0 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eF3 32.6 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 Ultimax II UMII18\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\"\u003e3.40\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\"\u003e27.0\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\"\u003e32.6\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\"\u003e39.0\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 27.0 Hz\u003c\/h3\u003e\n  \u003cp\u003eThe UMII18 is the 18 inch from Dayton's long-throw Ultimax II line: 22 Hz, a Qts of 0.53, 248.2 litres of Vas and 28 mm of excursion, rated 1200 W RMS. This cabinet gives it 3.40 cubic feet net behind a 2.25 inch three-layer baffle, vented at 27.0 Hz through a 39.0 square inch slot beside the woofer, for an anechoic F3 of 32.6 Hz in a 36 by 21 by 15 inch front-firing box.\u003c\/p\u003e\n  \u003cp\u003eThe slot is gated at 1440 W: the channel runs 16.3 m\/s and the mouth 10.4, and the cone peaks at 10.0 of its 28 mm with the subsonic filter in place. Passband ripple is 2.6 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\u003eDayton Audio logo acrylic\u003c\/h4\u003e\n\u003cp\u003eA glossy black acrylic insert with the Dayton 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\u003eMounting\u003c\/h4\u003e\n\u003cp\u003eThreaded inserts pressed into the baffle on the published 17.598 inch bolt circle, stainless machine screws included.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003ePort gated at 1440 W\u003c\/h4\u003e\n\u003cp\u003eThe 39.0 square inch slot beside the woofer is sized so the\n    channel runs 16.3 metres per second and the mouth 10.4 metres per second at 1.2 times the driver's rating, under the\n    17 metres per second where a slot starts to chuff. The channel runs 9.25 inches along its wall and turns once along the back wall for another 16.77 inches, which is why a 27.0 Hz tuning fits a 15.00 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\u003eThe Ultimax II UMII18 also builds in the Performance Optimized ported wedge, the smaller and cheaper box. The Professional cabinet is the step up for it: a 2.25 inch three-layer baffle with the woofer flush in the outer layer, and a slot port gated at 1440 W.\u003c\/p\u003e\n\u003c\/div\u003e\n    \u003cdiv class=\"df-card\"\u003e\n\u003ch4\u003eWhat the price covers\u003c\/h4\u003e\n\u003cp\u003eEvery Professional cabinet is priced the same way, by its size: this one is 6.56 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 75 lb parcel and checkout adds nothing. The Performance Optimized 18 inch ported wedge is $569.99. The $70 difference is the larger box and the port this driver needs to run at its rating.\u003c\/p\u003e\n\u003c\/div\u003e\n    \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 15.00\" 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. Inside the Professional envelope for a single 18, 36 inches wide, 21 tall and 15 deep. 18.504 inch frame, flush in the outer baffle layer, 16.839 inch cutout, 9.00 inches of mounting depth. Dayton print the bolt circle, so the threaded inserts are pressed at the shop. It ships as a parcel.\u003c\/p\u003e\n  \u003cp\u003eDayton publish a complete parameter table for the UMII18-22 that holds together on Qts, moving mass and motor strength. The Ultimax II product pages mislabel fitment (their cutout figure is the magnet), so the cutout, frame and depth come from Dayton's spec-sheet drawing. Displacement is not published; 0.181 cubic feet is our estimate. Tuning includes a 1.5 Hz fold loss that is an estimate, not a bench measurement.\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 21 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in\n  place the cone reaches 10.0 mm of its 28.0 mm at 1440 W.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":47424857899097,"sku":"Pro 18-P UMII18","price":639.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0689\/1389\/files\/Pro_18-P_UMII18_Front.jpg?v=1791685369","url":"https:\/\/audiointensity.com\/products\/professional-series-ported-18-enclosure-dayton-audio-ultimax-ii-umii18","provider":"Audio Intensity","version":"1.0","type":"link"}