The July 2021 edition of Voice Coil is now available and we have no doubt that it will be enjoyed by all loudspeaker industry professionals!This edition opens with a great Focus article on Adhesive Joints, Acoustic, and Treatments for Environmental Robustness. In this extensive and highly educational article, veteran industry consultant Mike Klasco (Menlo Scientific), updates his previous explorations into the world of "goo," as he likes to call the glue joints and diaphragm treatments used in speaker design. Because it's always great to learn something new, Klasco shares his latest findings in adhesives, damping, and cone, spider, and diaphragm coatings and binders, as he explains the intricate relationships that need to be considered of the acoustical characteristics of a loudspeaker's many glue joints. Within the article, readers will learn about adhesives and attachment techniques for the magnet structure to the frame, surround to cone and much more, helping us understand the influence of adhesives and resins on sound quality.
And to follow up in the best possible way, Mike Klasco and Nora Wong expand this knowledge with an updated and comprehensive directory of manufacturers and suppliers in this critical area. Covering Adhesives, Coatings, Sealants, Converters, and Dispensers, the 2021 edition of this valuable industry directory includes also new performance enhancing treatments, from resisting UV, hydrophobic (water) and olio-phobic, corrosion, detergents, sweat, and fungus to anti-microbial treatments. This year’s directory also includes additional speaker-centric converters that provide for secondary operations, including slitting, die cutting, coating and lamination, etc. A precious resource to help cut through the more than 1000 vendors of adhesives, coatings, and treatments, including only those that have optimized solutions for the speaker industry.
In this edition's Acoustic Patents columns, James Croft (Croft Acoustical) reviews a Bidirectional Speaker Using Bar Magnets, recently patented by Leeg Hyun Cho (Gyeonggi-do, Korea), Youngil Cho (Chicago, IL), and Christian Femrite (Westminster, CO) on behalf of Resonado Inc. (South Bend, IN). The patent in question will be familiar to many Voice Coil and audioXpress readers who have followed the news about this young company's developments and ambitions, including the January 2021 Voice Coil article, “A New Standard of Low Depth Racetrack Speaker Drivers with Flat Core Speaker Technology,” written by Brian (Youngil) Cho, the CEO of Resonado Labs.
As an experienced patent reviewer and speaker technology expert, Croft adds valuable context to the awarded patent, which apparently fails to mention much of the prior art that supports it. In his text, Croft also helps to better understand the patent's focus and benefits, which are hard to discern from even the published abstract. As he mentions, it is important to understand how a reinvention of an existing technology adds innovation and results of the latest advancements in materials and process science. Or sometimes simply an adaptation of the concept to a different use-model category. Particularly, because this patent mainly opens the doors to a scalable approach that has yet to conquer territory.
When we mentioned that both Voice Coil and audioXpress readers would be pleased with this edition, we were also referring to the fact that Vance Dickason's much-anticipated perspective of the Purifi Audio PTT6.5 Midbass Transducer is included this month. In his Test Bench of this 6.5” Midbass Transducer from Purifi Audio, Dickason highlights some of the new and unique engineering technology achievements, and explores step-by-step everything that makes this product a unique proposition.
The Purifi PTT6.5X04-NFA-01 midbass driver is an over-achiever, and to help understand why, Dickason talks with Lars Risbo about the research and thought process that lead to many of the features found in this woofer. Including the unique cone assembly that consists of a mildly curvilinear paper cone made with a proprietary fiber mix, a 3.13” concave dust cap, and a V-shaped edge reinforcing ring, the NBR surround, and of course the surround, which Dickason calls "probably the most unique surround in the history of Voice Coil’s Test Bench." All the details, exchanges with Lars Risbo, and of course the measurements, are in this edition of Test Bench.
Equally interesting, is a Test Bench characterization of the Beyma 12LEX1300Nd 12" driver from Beyma's New LEX Series. This latest design from Acustica Beyma, the company founded in 1969 and headquartered in Valencia, Spain, features a FEA-optimized neodymium magnet structure and 4" voice coil, and is targeted at two- and three-way PA speakers, being also optimized for band-pass subwoofer designs. The entire woofer is optimized with a rather substantial set of features for very high-performance.
This Test Bench fully explores the design and benefits and fully characterizes all the relevant design parameters of the Beyma 12LEX1300Nd, helping to understand the results obtained from the company's unique Maltcross forced convention cooling system that includes using the aluminum shorting ring as part of the cooling process.
This edition of Voice Coil closes with the traditional serving of Industry Watch articles, with corporate and brand moves, new product introductions, industry appointments, and updates from the Audio & Loudspeaker Technologies International (ALTI) association.The July 2021 edition of Voice Coil is available for download and already in the mail to print subscribers. Subscribers can go to - www.gotomyvcoil.com - to download this issue.
Remember, Voice Coil is available in print and download for all registered subscribers, free for industry professionals. To qualify for a free subscription to Voice Coil, or renew your subscription, go to: audioxpress.com/page/Voice-Coil-Subscriber-Services.html
Access to Digital Subscriptions
The pandemic has affected everyone’s lives, including those who provide our delivery service. With a surge in delivery demands and travel restrictions, we realize some of you may be experiencing significant delays in receiving your magazines. So KCK Media opened up its digital subscription platform to all print subscribers for no additional fee. To access it, just login using your subscriber number and post/zip code as displayed on your mailing label.
