Electrostatic Loudspeakers and Two Cutting-Edge High-End Tweeters in Voice Coil June 2023

Voice Coil June 2023 features an extensive patent review in James Croft's Acoustic Patents column. The topic is a 2014 patent awarded to Nokia, offering an opportunity to revisit the history of electrostatic loudspeakers, with insights from Tim Mellow, one of the two listed inventors. In Test Bench, Vance Dickason focuses on the D8404-552000 Ellipticor cloth diaphragm dome midrange from Scan-Speak, and characterizes the SB Acoustics TW29BNWG beryllium dome and waveguide from the brand's prestigious Satori line.

This review looks at a speaker patent, awarded to inventor Shengbo Li from Guangdong, China, on behalf of Harman International. The abstract from that patent details a speaker including one or multiple transducers, an enclosure, and a suspension mounted on the enclosure, wherein the suspension and the enclosure are configured such that the enclosure is capable of vibrating as a result of operation of the transducer so as to produce audible sound. You read it right, the enclosure is also a passive radiator!

This article examines an important patent filed in 2014 by F. Bruce Thigpen (Tallahassee, FL) and granted in June 2016. Appearing both as the inventor and assignee, Thigpen describes a rotary sound transducer having an improved output at higher frequencies. Thigpen has been working on this type of device for more than a decade and has advanced what was already a very difficult engineering achievement, to a more sophisticated structure that apparently raises the general performance and high frequency limits beyond what was thought possible with this architecture. This article was originally published in Voice Coil, July 2017.

The April 2023 issue of Voice Coil reveals the genesis of Echo Test + Measurement and its AIO Test System. As scheduled, there's an updated industry directory of Cable and Connector vendors, James Croft reviews a key Polk Audio patent that expands on its Polk SDA loudspeaker prior art now in a more compact enclosure. And on Test Bench, Vance Dickason focus on the characterization of the innovative TW045WA01 dual-diaphragm tweeter from Wavecor.

AntennaWare Ltd, specialists in solving body-blocking problems normally associated with close-range RF designs, has been awarded a European Patent which is expected to have important implications for enabling implantable devices within the human body. The new multi-mode antenna from AntennaWare enables reliable and continuous communications even in next-generation medical applications or from sensors inside obstructed structures.

In this issue of Voice Coil, Mike Klasco shares his experience dealing with sustainability and other noble goals, an article that was greatly inspired by the effort to compile another updated Speaker Enclosure Vendor Directory for 2023. In Acoustic Patents, James Croft explains how Yamaha recently invented a clever way to use a Class-D amplifier to bend the infamous "Hofmann’s Iron Law." And Vance Dickason takes the new 10HX230 10" coaxial professional driver from Faital Pro to his Test Bench.

The brand new generation of Beyma compression drivers originates from an intense R&D effort and two patent-pending innovations. Unveiled at ISE 2013, Beyma's four base designs with 2 throat sizes, 4 voice coil diameters, 3 diaphragm materials and 2 magnet types, allow for a total of 12 new models (for now). Scheduled to be launched progressively during 2023, these new Beyma state-of-the-art high frequency transducers deliver new exciting possibilities for speaker designs.

The patent reviewed here was granted to inventors Robert G. Johnston (Amprior Ontario, CA), and Sanford M.Gross (Owings Mills, MD), respectively the head of engineering of GoldenEar Technology, and one of its co-founders. The patent describes a subwoofer with two drivers on each side plus one passive radiator facing up and one passive radiator facing down. The passive radiator facing down effectively couples acoustic energy at very low frequencies into the floor.

James Croft explores patents granted to Mattias and Timothy Scheek, on behalf of Mayht Holding B.V. Our readers will recognize the name from the April 2022 announcement of the acquisition by Sonos of Mayht Holding BV, for "$100 million in existing cash on hand.” Having followed their work through a number of patent publications, Mayht's technology triggered Croft's curiosity, for its unconventional structural designs, appearing to represent fresh thinking. This article was originally published in Voice Coil, July 2022.

Happy 36th Anniversary Voice Coil! The November 2022 issue of Voice Coil once again celebrates the launch of this periodical as an information resource for the loudspeaker industry. Also, this month, Mike Klasco writes about technologies and solutions to enhance low-frequency performance, and James Croft reviews a recent patent awarded to Panasonic for a loudspeaker arrangement for a Near to the Ear Subwoofer in a car seat. For this month's Test Bench, Vance Dickason characterizes the 6CXN36 coaxial 6.5” pro sound driver from B&C Speakers, and Wavecor’s FR4X-6WA01 compact oval full-range driver. Now available in print, digital and online.