Patent Review: Vertically and Horizontally Balanced Subwoofer

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.

In its Standards Review article series, audioXpress published a two-part feature about the SuperSpeed USB 10 Gbps (USB 3.1 Gen 2) specification, the new USB Type-C interface, and Thunderbolt 3 technology. The second part examines how these technologies have evolved, how they work together, and the implications of USB Audio Device Class 3.0 specification, which standardized audio over USB Type-C. These two articles were originally published in audioXpress, December 2016 and January 2017.

This month’s Test Bench samples came from US OEM, Dayton Audio. I received a home audio 6.5” woofer, the DSA175, from the brand’s popular Designer Series of aluminum cone woofers. Each product in this line incorporates proprietary stamped steel frame with a thin mounting lip that enables front mounting without insetting the driver (surface mounted), high relative XMAX, with paper cones for the DS series and aluminum cones for the DSA series. This article was originally published in Voice Coil, December 2016.

This month’s Test Bench measures Eighteen Sound’s ND3ST 1.4” compression driver in combination with the Eighteen Sound XT1464 60° × 50° horn. The ND3ST 1.4 inch exit Natural Sound neodymium high frequency compression driver has been designed to fulfil very high quality sound reinforcement applications. This article was originally published in Voice Coil, December 2016.

Since 2009, Vesper has built a broad and deep patent portfolio around its proprietary MEMS piezoelectric technology, which works quite differently from conventional capacitive MEMS microphones. As Matt Crowley, CEO of Vesper, says during an interview with Voice Coil, “We are just beginning to realize the potential of piezoelectric MEMS microphones.” This article was originally published in Voice Coil, December 2016.

Stuart Yaniger reviews a complete series of professional-grade measurement microphones from PCB Piezotronics, specifically, the 378A04 free-field microphone, the 378B02 free-field microphone, the 378A21 diffuse-field microphone, and the 130E20 array microphone. This article was originally published in audioXpress, December 2016.

Voice Coil December 2016 features a Spotlight article on Vesper’s new and revolutionary proprietary MEMS piezoelectric transducer architecture, a comprehensive Directory of Measurement Microphones and related solutions, and the always indispensable Acoustic Patents article, which discusses an interesting new subwoofer design. Vance Dickason characterizes a new compression driver from Eighteen Sound and a mid-bass woofer from Dayton Audio and remembers the notable life and work of industry pioneer Leo Beranek (September 15, 1914 – October 16, 2016). Now available online!

audioXpress December 2016 is now ready to download. Our Standards Review article explains the fundamentals of the USB 3.1, USB Type-C, and Thunderbolt 3 specifications. We review four measurement microphones from PCB Piezotronics, the Mytek Digital Brooklyn DAC, the new miniDSP DDRC-24 processor, and we feature a Retro-Style High-Fidelity Preamplifier for DIY enthusiasts. This is an issue no one will want to miss.