{"product_id":"professional-series-ported-8-enclosure-dayton-audio-ultimax-ii-umii8","title":"Dayton Audio Ultimax II UMII8 Box: Ported 8\" 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 8\" Ported\u003c\/h2\u003e\n  \u003cp\u003eOne Ultimax II UMII8 in a front-firing Professional box, vented at 34.0 Hz on a three-layer flush-mount baffle\u003c\/p\u003e\n  \u003cdiv class=\"df-badges\"\u003e\n    \u003cspan class=\"df-badge\"\u003e1.16 cu ft net\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eTuned 34.0 Hz\u003c\/span\u003e\n    \u003cspan class=\"df-badge\"\u003eF3 28.5 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 UMII8\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\"\u003e1.16\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\"\u003e34.0\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\"\u003e28.5\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\"\u003e18.8\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 34.0 Hz\u003c\/h3\u003e\n  \u003cp\u003eThe UMII8 is the 8 inch from Dayton's long-throw Ultimax II line: 46 Hz, a Qts of 0.75, 8.4 litres of Vas and 18 mm of excursion, rated 400 W RMS. This cabinet gives it 1.16 cubic feet net behind a 2.25 inch three-layer baffle, vented at 34.0 Hz through an 18.8 square inch slot beside the woofer, for an anechoic F3 of 28.5 Hz in a 30 by 14 by 11.5 inch front-firing box.\u003c\/p\u003e\n  \u003cp\u003eThe slot is gated at 480 W: the channel runs 19.6 m\/s and the mouth 10.9, and the cone peaks at 12.1 of its 18 mm with the subsonic filter in place. Passband ripple is 1.7 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 7.874 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 480 W\u003c\/h4\u003e\n\u003cp\u003eThe 18.8 square inch slot beside the woofer is sized so the\n    channel runs 19.6 metres per second and the mouth 10.9 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 6.25 inches along its wall and turns once along the back wall for another 18.50 inches, which is why a 34.0 Hz tuning fits an 11.50 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 UMII8 also builds in the Performance Optimized ported down-fire, 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 480 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 2.80 cubic feet outside. Delivery to the 48 states is inside the price; it ships as a 48 lb parcel and checkout adds nothing.\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\u003e30.00\" W x 14.00\" H x 11.50\" 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 8, 30 inches wide, 14 tall and 11.5 deep. 8.425 inch frame, flush in the outer baffle layer, 7.311 inch cutout, 5.67 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 UMII8-22 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; 0.059 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 27 Hz subsonic filter, 24 dB per octave. Below tuning the vent stops loading the cone; with the filter in\n  place the cone reaches 12.1 mm of its 18.0 mm at 480 W.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Proline X","offers":[{"title":"Default Title","offer_id":47424823689305,"sku":"Pro 8-P UMII8","price":395.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0689\/1389\/files\/Pro_8-P_UMII8_Front.jpg?v=1791685202","url":"https:\/\/audiointensity.com\/products\/professional-series-ported-8-enclosure-dayton-audio-ultimax-ii-umii8","provider":"Audio Intensity","version":"1.0","type":"link"}