All items written by James Croft

Patent Review: Virtual Height Filter for Reflected Sound Rendering Using Upward Firing Drivers

February 17, 2022 by James Croft

Patent Review: Virtual Height Filter for Reflected Sound Rendering Using Upward Firing Drivers

This review discusses a patent that applies to speakers designed for new immersive audio formats in home applications and Dolby Atmos, in particular. Not surprisingly, the patent was awarded to Dolby Laboratories Licensing Corp. As the patent was granted, Voice Coil provided an extensive and informative review - recommended reading for anyone considering entering this important home-theater market segment. This article was originally published in Voice Coil, February 2016.

Patent Review: Extended Duct with Damping for Improved Speaker Performance

January 11, 2022 by James Croft

Patent Review: Extended Duct with Damping for Improved Speaker Performance

This article reviews a patent granted to Apple, describing an electronic audio device including an enclosure having an acoustic output opening and a speaker positioned within the enclosure, as implemented in the company’s range of iMac desktop computers. The speaker and the acoustic output opening are acoustically coupled by an acoustic output pathway and damping chamber. Apple’s patent cites the Matsushita patent as prior art, but this is a more developed concept. This article was originally published in Voice Coil, December 2015.

Patent Review: Loudspeaker Having a Passive Radiator US9426548B2

January 3, 2022 by James Croft

Patent Review: Loudspeaker Having a Passive Radiator US9426548B2

This article discusses a very interesting design and patent granted in August 2015 to Gary A. Rayner and James C. Larsen, as the inventors, on behalf of Treefrong Developments, from San Diego, CA. The patent abstract details a loudspeaker using one or more active drivers, with a passive radiator connected to each driver and dedicated processors and amplifier per channel - a slightly different approach to a familiar concept. This article was originally published in Voice Coil, November 2015.

Patent Review: Acoustical Window Assembly for Vehicle and Home Theater Solution

December 29, 2021 by James Croft

Patent Review: Acoustical Window Assembly for Vehicle and Home Theater Solution

James Croft reviews two patents for a new type of subwoofer architecture. The first is intended for use in an automobile and the second, for use in a domestic listening room. The first patent relates to an “Acoustical Window Assembly for Vehicle,” while the second describes a home-theater solution using essentially the same concept, adapted to one or more home windows. Both patents were awarded to Magna International, Inc. This article was originally published in Voice Coil, October 2015.

Patent Review: The Zoltan Bay Loudspeaker Patent

November 3, 2021 by James Croft

Patent Review: The Zoltan Bay Loudspeaker Patent

In this article, James Croft reviews a loudspeaker patent granted in 2015 to Zoltan Bay (Tiszaalpar, Hungary). The invention, which is the foundation for the BRS tweeter used in a remarkable series of Bayz Audio loudspeakers, basically describes a horizontally, omnidirectional transducer, using a multiple set of four to eight rolling, half-cylinder film diaphragms arranged in a circle to form a generally omni-directional radiator. This article was originally published in Voice Coil, September 2015.

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

October 27, 2021 by James Croft

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.

Patent Review: Desktop Audio Monitor System and Method

August 24, 2021 by James Croft

Patent Review: Desktop Audio Monitor System and Method

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.

Patent Review: Definitive Technology Bipolar Speaker with Improved Clarity

July 14, 2021 by James Croft

Patent Review: Definitive Technology Bipolar Speaker with Improved Clarity

An interesting patent review of a Bipolar Speaker assigned to Definitive Technology, the Maryland-based company that is now part of Sound United. The patent describes a forward-focused bipolar loudspeaker design with front-facing and rear facing driver-arrays, adjusted to generate a front-to-back acoustical output balance equal to a 2:1 ratio (about 6dB reduction) in the output of the rear firing transducers relative to the direct forward output. This article was originally published in Voice Coil, June 2015

Patent Review: Bose Transmission Line Loudspeaker

July 7, 2021 by James Croft

Patent Review: Bose Transmission Line Loudspeaker

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

Patent Review: A Circular Shaped Planar Speaker System

April 7, 2021 by James Croft

Patent Review: A Circular Shaped Planar Speaker System

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.

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