Patent Review: Dual Coil Electrodynamic Transducer with Channels for Voice Coil Cooling

James Croft reviews a published design submitted on behalf of Harman International Industries on January 2017. The design details an important approach to solving the everlasting problems of heat generation that limits the power handling capacity and the distortion-free acoustic output capability of loudspeakers, as well as their efficiency as electroacoustical transducers. This article was originally published in Voice Coil, September 2018.​​​​​​​

In this Test Bench, I characterized two new 28 mm dome tweeters from Dayton Audio — the RST28A-4 and the RST28F-4 from the Dayton Reference Series. Both are similar tweeters that share pretty much the same platform with the primary difference being the RST28A-4 uses an 30 mm aluminum dome and the RST28F-4 has a 30 mm coated silk dome. This article was originally published in Voice Coil, September 2018.

This Test Bench characterizes the new Dayton Audio Epique E160CF-8 midbass driver, from the company’s new Epique high-end transducer line. This new 5.25” midwoofer is Dayton’s entry into the ultra-high-end driver market. Dayton built it with the intention of competing with the likes of SEAS, Scan-Speak, Eton, Accuton, and Morel. Applications for the E160CF-8 include use as a midrange in a multi-way speaker or as a woofer in a two-way speaker. This article was originally published in Voice Coil, September 2018.

Ward Maas writes about Danish-sensation Merus Audio, the company founded in 2010 by Hans Hasselby-Andersen and Mikkel Hoyerby, and recently acquired by Infineon Technologies. The article recalls how this Copenhagen-based start-up quickly ascended in the audio industry with its new generation of energy-efficient integrated Class-D amplifier solutions. This article was originally published in audioXpress. September 2018.

Voice Coil September 2018 edition is now available and features all the essential information about this year’s CEDIA Expo event. James Croft reviews a Harman patent for a multi-coil transducer approach to improve the cooling structure of loudspeakers, while Vance Dickason characterizes the ambitious new Dayton Audio Epique E160CF-8 midbass driver and two new 28 mm dome tweeters also from Dayton Audio — the RST28A-4 and the RST28F-4. Now available for download or in print.

Once again, audioXpress focuses on loudspeaker building, design, and testing in its September edition. We have three great speaker DIY projects that are certain to inspire our readers, Geoff Hill explains how speaker measurements are evolving under the latest Audio Engineering Society (AES) efforts, and Richard Honeycutt writes about modulation distortion in loudspeakers. We interviewed Crispin Herrod-Taylor, the designer of the amazing SoundBuckets portable speakers, we explain all you need to know about the latest HDMI Enhanced Audio Return Channel (eARC) specification, and Ward Maas tells the story of Infineon's new energy-efficient multi-level amplifiers.