Dayton UltiMax 15" 'Home Theater' DIY subwoofer - AVS Forum
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post #1 of 2 Old 01-31-2013, 11:44 AM - Thread Starter
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Dayton Audio has introduced new 15" subwoofer - aimed squarely at the DIY subwoofer crowd: the Dayton UltiMax 15". Priced just under $200, it is a feature-packed contender for anyone interested in building their own 15" subwoofer. Moving more air = more bass and there are only two ways to move more air - a larger cone or a higher xmax (more excursion). DIY subwoofer builders are drawn to drivers that have plenty of both - 15" and 18" subs are standard issue for DIY. This new Dayton has 3/4" xmax, which is quite good at this price. That's not surprising, Dayton Audio is a value-oriented manufacturer of both DIY components and finished audio-related products - for example their $39.95/pair bookshelf speakers were well reviewed by Stereophile magazine and enjoy good ratings on Amazon.

With the UltiMax 15", Dayton is now fielding a subwoofer with features that translate into better performance, including copper shorting rings, dual spiders and a 'tall boy' surround, all of which help the sub achieve it's 19mm rated xmax. Home Theater is much more demanding than (most) music when it comes to the deepest bass, which is why subwoofers like this are becoming more popular.
Product Highlights
• Dual 2 ohm, 2-layer copper voice coils
• Large vented pole piece and under-spider venting
• Black anodized aluminum former and black pole improves heat dissipation
• Thick, one-piece Nomex honeycomb covered with woven heavy-duty glass-fiber
• Tall-boy rubber surround for extra-long linear excursion without reducing cone surface area
• Dual linear stiffness spiders limit distortion and rocking modes
• Copper shorting rings and cap reduce distortion


The subwoofer handles 800 watts RMS, features 19mm of XMAX and is a 2-ohm, dual voice coil design. Remarkably specific instructions are given for minimum and maximum enclosure sizes as well as potential tuning:
Cabinet recommendations:
• Sealed 3.1 cubic ft. (net internal) with 1 lbs. of Acousta-Stuf polyfill, f3 of 35 Hz with a 0.707 Qtc alignment
• Vented 6.0 cubic ft. (net internal, not including driver or port volume) with 6 lbs. of Acousta-Stuf tuned to 18 Hz with two 4" diameter by 26" long flared ports for an f3 of 22 Hz. Larger cabinets and lower tuning frequencies are possible. The largest recommended cabinet is 10.5 cubic feet tuned to 16 Hz using two 4" diameter ports that are 21" long for an f3 of 19 Hz.

There is an AVS forum thread for this new driver

I intend to 'model' this new driver in software to explore some build possibilities, and I'm guessing others will as well.

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post #2 of 2 Old 02-01-2013, 01:01 PM
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Well, for new guys, it takes all the guess work out of deciding on an enclosure. IMO it's a pretty good idea to have specific instructions. How the driver preforms in those boxes is another matter.

Blasting brown notes for 10 years and counting!

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