Ideas for Speaker Enclosures Now in Voice Coil March 2024

Voice Coil March 2024 focuses on speaker enclosures with a unique directory of innovative material ideas, followed by an always insightful patent review, where James Croft revisits the pivotal Dinaburg invention. For Test Bench, this month Vance Dickason characterizes the SIG180-4 6.5” woofer from Dayton Audio’s Signature Series, and a midbass shallow-profile 6.5” driver, the Stereo Integrity TM65 mkIV.

In the August 2018 issue of Voice Coil, James Croft combined the review of two important independent patents, having in common the fact that they try to address the shortcomings of the work of Dr. Oskar Heil with his Air Motion Transformer (AMT) woofer system. Following a review of a Tymphany patent, Croft reviewed a related patent for an Air Motion Transformer Passive Radiator, invented by and awarded to Eugene Julius Christensen (Aspen, CO).

We looked at the popular articles of 2023 in audioXpress.com (including selected articles from audioXpress and Voice Coil magazines), and we created this Top 11 list of news stories and online articles. As the number of visitors and pageviews registered by audioXpress.com continues to break records every year, visitors from all over the world returned more often to read the many stories available. Which of the topics and stories published online in 2023 were the most popular? Here are the results!

This article reviews an intriguing new patent awarded to Turtle Beach Corp. addressing a new emitter circuit for providing a bias voltage, which is key for the development of electrostatic loudspeakers. Extremely aware of the techniques and historical perspective of the development in this area, Croft provides a complete overview of all the challenges, implications and merits of this patent and prior art. This article was originally published in Voice Coil, July 2018.

From midbass to bass, Voice Coil November 2023 provides the lowdown on some of the loudspeaker industry's most interesting developments. James Croft explores a recently granted "Venturi expander" patent. Mike Klasco explores speaker design and signal processing techniques to achieve more bass, and Vance Dickason characterizes the Wavecor WF152BD09-04 6" midbass driver, and the UF295FAS Ultra Flat Series 10" thin-profile dipole woofer from Neotera.

In this article James Croft reviews a patent claimed by Leeg Hyun Cho (Gyeonggi-do, Korea), Youngil Cho (Chicago, IL), and Christian Femrite (Westminster, CO) on behalf of Resonado. The patent in question will be familiar to many Voice Coil and audioXpress readers who have followed the news about this young company's developments. As an experienced patent reviewer and speaker technology expert, Croft adds valuable context to the awarded patent. This article was originally published in Voice Coil, July 2021

In the October 2023 issue of Voice Coil, James Croft reviews an active noise control enclosure system, and Mike Klasco and Nora Wong provide an updated directory of Integrated Electronics for Loudspeakers. Vance Dickason offers three different driver characterizations, starting with the AMT100H driver from Eighteen Sound. Next up, he tests an updated version of the popular TW030WA23/24 tweeter from Wavecor. And finally, measures the Scan-Speak D2008/2010, the revised version of the classic dome tweeter from the Danish brand.

In this article, James Croft discusses a patent granted to Curtis Graber (Woodburn, IN) that describes a radial acoustic speaker assembly including a transducer and a plurality of segmented spiral horns acoustically coupled to the transducer, each with its acoustical path. This new patent by prolific audio inventor, Curtis Graber, uses a new multi-spiral waveguide structure driven by a single transducer and has clear advantages over prior art. This article was originally published in Voice Coil, May 2018.

This article discusses a patent originally claimed in 2013 on a Double Coil Speaker design, which was granted in 2017 to Friedrich Reining (Vienna, Austria), on behalf of Sound Solutions International. The abstract from the patent details an audio system comprising an electro-acoustic transducer having two stacked voice coils mechanically linked to a membrane. James Croft discusses multiple approaches in similar concepts, and notes that the current state of technology might finally create a way to explore it in commercial products. This article was originally published in Voice Coil, March 2018.

Renowned audio speaker design, David W. Gunness, now with Fulcrum Acoustic, and previously with Electro-Voice and Eastern Acoustic Works, is no stranger to this field of research where he holds numerous patents.This review is a fascinating read, especially given that Fulcrum has already proven the validity of the proposed designs in actual products. It seems clear that Gunness achieved “a very good design that should advance the art in the category of cardioid devices,” as Croft notes.