Patent Review: Low-Profile Loudspeaker Transducer

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.

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.

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.

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 article, James Croft reviews a generic “Loudspeaker” concept patent, granted to Teppei Yamada, of Tokyo, Japan, on behalf of Zorzo Co., Ltd. and which describes a somewhat surprising concept of a loudspeaker that includes a hermetically sealed enclosure, with a driver outside of an enclosure and a second driver inside, with a pipe communicating between the two drivers. The second driver is configured to output a signal of opposite phase to that of the first driver. This article was originally published in Voice Coil, October 2016.

In this article, James Croft looks at a patent awarded to David Russell (Toronto, CA); and John French (Caledon, East, CA) on behalf of Audera Acoustics, Inc., Schomberg CA. The patent describes a generic acoustic high displacement transducer system, containing a diaphragm position sensing module, a controller with a transmitter, so that the voice coil moves at least partially in response to the control signal.

This article reviews a patent originally granted to inventors Philip R. Clements; (Tempe, AZ), Boaz Shalev; (Needham, MA), and James Joseph Croft, III; (Bellevue, WA), which has now expired. The patent describes a low-frequency transducer system with a multi-compression chamber, where an inverse horn structure is employed in combination with a resonance-distortion filter chamber. This was the third patent granted on Atlantic Technology’s low frequency system known by the trademark name H-PAS (High Pressure Acceleration System). This article was originally published in Voice Coil, September 2016.