Patent Review: A New Electro Acoustic Drive System With Sensor from Fraunhofer

In this article, James Croft dives in an interesting loudspeaker patent (US20150146910A1), awarded May 28, 2015 to multiple inventors from the Fraunhofer-Gesellschaft Institute in Munich, Germany. The patent describes a diaphragm drive system with a conventional electromagnetic motor and corrective piezoelectric elements that drive the suspension from a sensor that detects the nonlinearity and provides the corrective signal. This article was originally published in Voice Coil, September 2015.

In this patents review, James Croft looks at one of the most interesting concepts for a “Desktop Audio Monitor System and Method.” US Patent 9036837, was granted in 2015 to James Tuomy (Framingham, MA), Barry Michael Kosherick (Hudson, MA), Laurie Wilk (Framingham, MA), and J. Richard Aylward (Ashland, MA). The concept was actually introduced to the market a year earlier, and made its big debut at the NAMM Show 2015, by Phasx Technologies. This article was originally published in Voice Coil, August 2015.

In this Voice Coil Acoustic Patents article, James Croft discusses an interesting Transmission Line Loudspeaker patent assigned to three engineers from Bose regarding an electro-acoustic driver and acoustic waveguide that includes “an enclosure, an acoustic transmission line formed within the enclosure, and a plurality of acoustic transducers contained within the enclosure and disposed along a length of the acoustic transmission line.” As Croft notes, this seems to be an improvement over the Tapped Horn loudspeaker architecture patented by Tom Danley, assigned 10 years ago. This article was originally published in Voice Coil, June 2015

Voice Coil June 2021 explores the CTA-2010 Standard Method of Measurement for Subwoofers, and follows with a scheduled directory of Headphone Test & Measurement Equipment suppliers and solutions. James Croft reviews an interesting patent exploring a combination design with dual-diaphragm compression drivers, and Vance Dickason characterizes the much-anticipated SB Acoustics Satori MW16TX-8 Textreme Cone 6.5" Woofer, and the very original BDNC BGF-46166-18-4-003 Glass-Composite Diaphragm Woofer. Now available in print and digital.

The patent in review was granted in February 2015 to inventor Zhijun Zhao (West Bloomfield, MI) on behalf of Harman International Industries. As James Croft notes, planar magnetic transducers are often preferred for their thin form factor, ideal for shallow mounting spaces where a standard transducer may not fit, such as in-wall systems and automotive applications. The patent in review offers a practical solution for an oval or circular format planar magnetic transducer for such applications. This article was original published in Voice Coil, April 2015.

The April 2021 edition of Voice Coil is now available and combines a wide range of topics for loudspeaker industry professionals. Starting with "Practical Considerations for Quality Control Testing of Loudspeakers," to an overview of innovations in wires and connectors, and a directory of cable and connector vendors. And, Vance Dickason looks at two compression drivers matched with factory-supplied horns - the ND1TP from Eighteen Sound and the CD-11Nd from Acustica Beyma. Now available in print and digital.

Following a recent exchange with loudspeaker designer and inventor John J. Gaudreault, we decided to revisit the very original Planar-Pivot (Planot) Transducer, and make available the two related articles that were published by Voice Coil in its May 2011 edition, and the respective Patent Review by James Croft published in the August edition of that same year. Hoping this will inspire some commercial implementations of this interesting concept, available for licensing.

James Croft reviews two loudspeaker-related patents as a tribute to David John Graebener, who passed away on January 3, 2015. First James Croft reviews the planar-magnetic electro-acoustic transducer he patented together with Graebener, followed by a single-end planar magnetic speaker system, David’s key patent. These were the first and second of the Single-Ended, Neodymium planar magnetic transducer patents David Graebener was granted. This article was originally published in Voice Coil, March 2015.

The February 2021 edition of Voice Coil offers an overview of the Cone Industry in 2021, with an updated directory of loudspeaker cone, diaphragms and suppliers of relevant materials and components. Next up, James Croft reviews an interesting patent for a "Directional Loudspeaker," claimed by Dutch & Dutch BV, and Vance Dickason focuses his measurements on two small-sized drivers, typical of today's most popular consumer products. The first in Test Bench is the Wavecor FR070WA05, a 2.75" aluminum cone full-range driver, and the second is the AUGWL0006-JN01, a new 2.25" woofer from Eastech’s Punktkilde lineup.

This patent review looks at a “Loudspeaker with a Wave Guide” (Patent Number: US20140369543) by inventors Jussi Vaisanen and Ilpo Martikainen from Finish company Genelec. This patent relates to the Genelec 8351 Acoustically Coaxial Smart Active Monitor (SAM) monitor, originally launched in 2016. Later in 2017, Genelec expanded the concept into a complete series of Coaxial Active Monitors, “The Ones”. This article was originally published in Voice Coil, February 2015.