Product Design | Audio Electronics | Acoustics | DIY | Audio Innovations
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Bang & Olufsen Breaks the Mold on Home Speakers with Future-Proofed Beosound Level |
Bang & Olufsen introduced Beosound Level, a portable wireless home speaker that expands the notion of what is possible with today's technology. Described by the Danish luxury audio brand as a home speaker made to move, the Beosound Level is unique in every aspect. First, it doesn't look like a speaker - but B&O has done that before. Second, it’s portable and able to adjust its sound to compensate for any position or room. Third, it's a connected speaker supporting all the latest technologies, but its connectivity module can be replaced in the future. Read More
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Webinar about Intellectual Property Issues across the Production Chain |
The AES Audio Product Education Institute (APEI), an initiative of the Audio Engineering Society (AES) to focus on promoting methodologies, practices, and technologies involved in developing and bringing audio products to market, will host its fifth online event addressing Supply Chain & Sourcing on Wednesday, February 17 (12:00pm EST). The online event will feature leading experts in IP protection, counterfeiting, and authentication to discuss challenges and strategies in manufacturing audio products. Read More
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Picovoice Announces Voice Interfaces on the Edge With German Language Support and Plans to Go Multilingual |
Picovoice, a young company developing voice AI on the edge with on-device speech recognition and natural language understanding software, announced a new SDK for German language. The company allows developers to create and fully test voice experiences directly on its recently launched Picovoice Console platform, before exporting models that can run on-device with minimal latency. Picovoice also announced plans to release SDKs for French, Spanish, and Japanese . Read More
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UK Loudspeaker Manufacturer PMC Celebrates 30 Years of Loudspeaker Passion |
UK-based PMC is celebrating its 30th anniversary this year, marking three decades of “Best of British” loudspeaker design and manufacture for both the international professional music production and audiophile markets. From a modest start as two men in a garage to 30 years of the biggest movie soundtracks and albums in the world, the Professional Monitor Company Limited, had a remarkable trajectory grounded on a common devotion for transmission line designs and a fundamental belief in fidelity. Read More
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Sound United Uniquely Positioned for Automotive Market Growth with Acquisition of Bowers & Wilkins |
Following the recent Bowers & Wilkins acquisition, Sound United LLC - parent company to Denon, Marantz, Polk Audio, Definitive Technology, Classé, and Boston Acoustics - announced its intent to capitalize on Bowers & Wilkins’ in-depth knowledge of the automotive audio industry to expand its development into the growing automotive market. "Bowers & Wilkins’ heritage of automotive audio excellence empowers Sound United with deep well of knowledge, bettering its position for growth," the company states. Read More
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B&C Releases New FB464 Passive Crossover for DCX464 Coaxial Compression Driver |
Continuing to expand on the innovative breakthroughs made possible by its ME464 1.4-inch horn, designed to extract the full potential of the DCX464 coaxial compression driver, B&C Speakers announced availability of the FB464 passive crossover, making available a unique ready-to-use solution. Notable results from the research work efforts by the Italian professional audio manufacturer will greatly benefit integrators and speaker designers alike . Read More
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Audeze Announces Euclid Closed-Back Planar Magnetic In-Ear |
At first glance, one would be forgiven to think, "Did Audeze just dropped its first true wireless earbuds - and they're planar magnetic?" Well, not exactly - not yet, at least. The new Euclid are not mass produced TWS earbuds with batteries inside, but actually the highest-quality in-ear monitors (IEMs, if you will) handcrafted in California, and they’re proudly the company's first closed-back planar magnetic in-ear design . Read More
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ALTI-Expo 2021 Reschedules to October 24-25 with InfoComm |
With the announcement that AVIXA had decided to reschedule its InfoComm show from June to October 2021, other synchronized events are also forced to reschedule. That is what has happened with the Audio & Loudspeaker Technologies International’s (ALTI) own event, promoted just prior to the opening of the exhibition days of InfoComm at a nearby hotel. ALTI-Expo 2021, which was previously scheduled for June 14-15, has been rescheduled to October 24-25, 2021 . Read More
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Editor's Desk
J. Martins
Editor-in-Chief
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Constant Directivity Loudspeaker Research
Recognition Deserved to Don Keele
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D.B. (Don) Keele, Jr. has devoted his life to researching the characteristics of sound as it leaves its source, and its subsequent behavior while filling the listening environment. His work in the loudspeaker industry is recognized for groundbreaking (and patented) research of Constant Directivity and Bi-Radial high frequency horn concepts while working for several companies including Electro-Voice, JBL, Klipsch, Crown, and Harman International. Don Keele holds multiple patents in constant directivity loudspeaker horns, loudspeaker arrays, and signal processing.
Recently in this space, I highlighted a few important technical, scientific, and engineering awards that recognized with Oscars, Emmys, and Grammys the work of audio industry pioneers, and I even noted that the annual "award season" opened earlier with the CES Innovation Awards and the 36th NAMM Creative and Technical TEC Awards.
When the TEC Awards were confirmed in January during the NAMM Believe in Music Week, without an actual TEC Award ceremony, I (and apparently many other media colleagues) failed to acknowledge the earlier announced 2021 TECnology Hall of Fame Inductees. This is a very important industry recognition confirmed every year to honor and recognize audio products and innovations that have made a significant contribution to the advancement of audio technology. Apparently the awards were previously confirmed in December 2020 without much fanfare (the year was unusual in every way).
This year, there were five entries for the NAMM TECnology Hall of Fame, which is usually a longer list of inductees that our esteemed colleague George Petersen, currently the editor of FOH magazine, started to promote in 2004, becoming now an important contribution for the NAMM's initiative of the Museum of Making Music ( www.museumofmakingmusic.org).
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As a senior designer with Electro-Voice, Don Keele conceived and patented the Constant Directivity (CD) loudspeaker horn in 1975. In 2002, Keele was honored with a Scientific and Engineering Academy Award from the Academy of Motion Picture Arts and Sciences for work on Constant Directivity loudspeakers for cinema applications. |
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I am mentioning this important initiative to highlight the fact that this year the TECnology Hall of Fame expert panel confirmed the induction of a dear industry friend and audioXpress author, Don Keele, for his work in the design of constant directivity loudspeaker horns. Keele was the primary designer of the now recognized Electro-Voice "HR" series of constant directivity horns on which he also holds the patent. Other inductees to the 2021 TECnology Hall of Fame included Western Electric’s 639A ribbon/dynamic microphone; RCA’s 1957 Mark II Sound Synthesizer (the first programmable music synth); 3M’s 1968 M56 16 track recorder; and Ed Long for the Near-Field studio monitor concept in 1977. You can see all the details here.
While working as a senior designer with Electro-Voice in Buchanan, MI, Don Keele worked on the before mentioned high-frequency horns, but also in low-frequency vented-box loudspeaker systems - you can read something about his work on that specific area in an article published recently in audioXpress.
His work on constant directivity horns was highlighted by Charlie Hughes in an article originally published by Voice Coil in November 2010, "Understanding Horn Directivity Control". In that article, Hughes writes: “In 1975 Don Keele presented a paper at the 51st Convention of the Audio Engineering Society that introduced the modern Constant Directivity horn. This new horn design (new at that time) combined an exponential throat section, to provide good loading at lower frequencies, with a conical or straight wall section that provided a more uniform coverage pattern in the higher frequency region than a pure exponential horn.”
Later while working for Klipsch, JBL and Harman/Becker, Keele addressed the issue of beamwidth varying at different frequencies, undertaking a long and extensive research, extended for more than 45 years. His research work, with numerous patents granted, was recognized with the Richard C. Heyser Award for contributions to loudspeaker measurements in 2001, and a Scientific and Technical Academy Award from the Academy of Motion Picture Arts and Sciences in 2002.
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Following his extensive work with JBL and Harman on Constant Beamwidth Technology arrays, Don Keele designed a product for high end audio, available as the Dayton Audio Epique CBT24 Line Array Speaker - seen here on the left, side by side with an image of its patent from 2010, granted on behalf of Harman International, and an actual application of a CBT array used for sound reinforcement in a church in Raleigh, NC. |
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Particularly since 2008, when he resumed his own consultancy firm, specializing in loudspeaker horn design and loudspeaker array design work, Don Keele has been focusing his attention on column speakers and Constant Beamwidth Transducers (CBT) arrays. Keele is an ardent advocate and evangelist for the CBT arrays, which he believes have been demonstrated numerous times to vastly improve the sound field uniformity of existing line arrays and loudspeaker systems.
In a recent exchange I had with Don Keele, regarding the recent TECnology Hall of Fame announcement, he highlighted this same enthusiasm for the concept, which he sees as a natural evolution of that original Constant Directivity work that was now inducted. "For the last 20 years, my current research topic is CBT technology, which I pioneered (along with the US military in underwater sound in the late 1970s). I have written over 17 papers on the topic and given many presentations. This topic far out shadows my work on horns from 50 years ago (I’m 80 now!)."
More importantly, Keele regrets that, like so many important loudspeaker innovations, that work remains to be explored to its full potential. "I believe, my CBT work on constant directivity/coverage loudspeaker line arrays is truly revolutionary and it’s too bad that not many manufacturers haven’t picked up on the topic! It’s a shame that it hasn’t taken hold in the industry!"
I also believe there is a lot to consider in Keele's frustration. Because over the years I have seen no lack of similar statements from many senior design engineers who have contributed important advancements in loudspeakers - some of which originated actual working products - and remain forgotten or largely ignored, while intense research continues, fundamentally to address the very same problems that had already been addressed.
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D. B. (Don) Keele, Jr. is now principal consultant and owner of DBK Associates and Labs. Seen here with a CBT loudspeaker, a design which Siegfried Linquitz or Floyd Toole praised very highly. |
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Vanderveen Trans-SE10 Tube Amplifier Kit Secrets
By Menno van der Veen
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In this article for audioXpress, renowned tube expert Menno van der Veen explains everything about the Vanderveen Trans-SE10 amplifier, which is available as a DIY kit manufactured by Tentlabs. This letter-sized stereo amplifier is a single-ended design with an output power of 10W per channel, but there's a lot "under the hood" (and the glass) to understand. “Trans” indicates a method to minimize magnetic distortions in the output transformers and voltage distortions in the power tubes. The technique is based on local feedback with voltage-controlled current sources. The net result is remarkably detailed sound reproduction where the tubes’ second harmonic and output transformer magnetic distortions are minimized. In this article, Menno van der Veen explains the “why and how” of the unusual Vanderveen Trans-SE10 design. This article was originally published in audioXpress, January 2021. Read the Full Article Now Available Here
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The SDx10 Home Audio Woofer from CSS Audio
By Vance Dickason
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The driver under test in this Test bench is the SDx10 home audio woofer from Creative Sound Solutions (CSS) Audio, a company that was introduced to Voice Coil readers, with the LD25X tweeter, featured in the July 2020 issue. Now, CSS sent the 10" SDx10, using the same XBL^2 dual gap motor technology licensed from inventor Dan Wiggins. The CSS SDx10 also has a well-appointed feature set that includes a proprietary cast 12-spoke (6 twin spokes) cast-aluminum frame, a very stiff coated black paper/carbon fiber blended composite cone with a convex black hard paper dust cap, NBR surround, and semi-progressive cloth spider. All this is driven by a 2.4” diameter six-layer voice coil wound with round copper wire on a non-conducting former, with two 12mm thick ferrite magnets sandwiched between a thick XBL-configured front plate and black-plated thick T-yoke. The braided voice coil lead wires terminate to a plastic terminal block that incorporates two color-coded chrome binding posts. This article was originally published in Voice Coil, November 2020. Read the Full Article Now Available Here
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Advancing the Evolution
of Audio Technology
audioXpress features great articles, projects, tips, and techniques for the best in quality audio. It connects manufacturers and distributors with audio engineers and enthusiasts eager for innovative solutions in sound, acoustic, and electronics.
Voice Coil, the periodical for the loudspeaker industry, delivers product reviews, company profiles, industry news, and design tips straight to professional audio engineers and manufacturers who have the authority to make powerful purchasing decisions.
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