Loudspeaker Manufacturing, Patents, and Driver Characterizations in Voice Coil August 2022

August is traditionally the voice-coil-focused issue of Voice Coil, offering an always-valuable perspective on the state of the loudspeaker industry. In this issue, Mike Klasco discusses Audio Manufacturing in The Philippines, James Croft explores another key Mayht patent, and Vance Dickason measures and characterizes the B&C Speakers DE111-8 1" compression driver, and the MD60N-6 2.5” Dome Midrange from SB Acoustics' Satori line.

This article reviews a patent application submitted in 2010 by to two inventors, on behalf of Jazz Hipster Corp. (Taiwan), regarding an improved structure of a speaker using the surround to reduce the resistance of the diaphragm excursion, which helps to generate a more linear diaphragm movement, with less resistance, and reduced distortion. As James Croft noted, the approach had been used in the past, but its use decreased due to the high-performance achieved with well-designed roll-surrounds, at a lower cost. No surprisingly this patent was subsequently abandoned.

We're off to a great start in 2022. Starting with details about the promise of Iron Nitride (FeN) magnets, followed by an article about Liquid Injection Molding Silicon for Next-Generation Headphone Surrounds. Next up, James Croft reviews a surround speaker patent granted to Klipsch, and Vance Dickason characterizes the Satori MW13TX-4 TPCD-cone woofer from SB Acoustics and the high-power WF275BD01 10.75" woofer from Wavecor. All articles now available to read online, PDF and print.

Martin Audio has extended its list of notable patents with the addition of a United Kingdom Patent for its XE stage monitor waveguide. The patent covers the use of Martin Audio’s differential dispersion coaxial drive units and the continuation of their waveguide shape to form the baffle, as seen in the XE monitors to achieve the desired HF coverage. The geometry of the static HF horn, the LF cone/moving waveguides and the static baffle combine to form a single HF horn.

The October 2021 edition of Voice Coil discusses "The State of Loudspeaker Magnetics," with an annual overview of these critical industry components and materials for loudspeakers, complemented with an updated industry directory focused on Integrated Electronics. James Croft covers a patent awarded to Coastal Source for the variable waveguide speaker control, while Vance Dickason characterizes the powerful 15DS100 professional subwoofer from B&C Speakers, and Eighteen Sound's latest ND2T 1.4” neodymium compression driver. Now available in print, immediate online access or download.

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

Recently, Dinaburg Technology, based in Dallas, TX, was issued their first US patent for an electro-dynamic loudspeaker with an integrated coaxial passive ring radiator. Mikhail Dinaburg, noted physicist and the patent inventor, uncovered some missing elements in previous coax and passive radiator work and set out to prove it. Dinaburg’s patent discloses techniques for higher performance sound reproduction, enabling lower distortion, extended frequency range, higher efficiency, and improved speech intelligibility. The invention has wide applications and scales from a earphone driver to near-field studio monitors, ceiling speakers, under couch subwoofers to the largest concert subwoofers.

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.