Patent Review: Passive Radiator Structure

This article analyzes a patent awarded in March 2017 to Yeh-Feng Chou (Taiwan), on behalf of Meiloon Industrial Co., Ltd., of a new Passive Radiator Structure, which adds some desirable attributes and improved performance. As the abstract details, the passive radiator structure includes a surround suspension, a frame, and a web-like spider having a plurality of suspension arms integrally extended to between the diaphragm and the frame, which together minimize sound distortion, increase compliance and upgrade efficiency.

This review looks at a patent awarded in October 2016 to George Bullimore, on behalf of Tymphany. Considering the number of patents on shallow drivers, and the fact that the inventor also previously developed transducers for Harman International and holds other key patents, this is no doubt an interesting document to analyze in depth. This article was originally published in Voice Coil, May 2017.

This review looks at a patent of parametric loudspeaker awarded in November 2016 to Luke Batchelder (Somers, NY), and J. Samuel Batchelder (Somers, NY) on behalf of Convey Technology, Inc. (Somers, NY). As James Croft (Croft Acoustical) comments in this patent review: "The parametric loudspeaker is one of those technologies that get rediscovered and “invented” about every 10 years." This article was originally published in Voice Coil, February 2017.

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.

Having reviewed previously one of the early Mayht Holding B.V. patents covering their general bipolar, interleaved multiple motor structure architecture, James Croft reviews the most recent US publication (2022). This one addresses the most dramatic claim for the Mayht transducer technology of the ability to provide a greater-than 10x reduction in enclosure volume, while maintaining the same efficiency and bandwidth as compared to the current state of the art. This article was originally published in Voice Coil, August 2022

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.

James Croft reviews another patent of a concept ignoring abundant prior art, which apparently wasn’t scrutinized by industry experts - as it should. The patent "Dynamic Acoustic Waveguide," was awarded to William Eugene Wheeler (High Ridge, MO) as inventor and assignee, and describes a “loudspeaker and a method of operation that allow for the production and emphasis of extremely low bass tones.

Sometimes James Croft reviews patents that are hard to understand how could they possibly have materialized. This patent describes a “System and Method for Improved Audio Perception” and was granted to Yair Raz (inventor) on behalf of Innovo IP, LLC (Aventura, FL). The “invention” describes “methods of Audio Signal Personalized Enhancement for optimal listening to music using a combination of hearing test, audio signal compensation, and signal processing algorithms. A description that could easily be applied to dozens of currently available products. This article was originally published in Voice Coil, November 2016.

In this edition of Voice Coil, Mike Klasco writes about Dr. Kurt Müller's 100-Year Anniversary, Mike Klasco and Nora Wong compiled an updated Integrated Electronics for Loudspeakers directory, and James Croft reviews an intriguing patent of a Vertically and Horizontally Balanced Subwoofer. For this issue's Test Bench, Vance Dickason focused his full attention on another innovative driver from Purifi Audio, this time the PTT5.25X04-NFA-01 5.25” Midbass Woofer.