The January 2022 edition of audioXpress leads off with an eye-opening Market Update report on Speaker Technology. Mike Klasco and J. Martins explore new materials and engineering approaches for loudspeakers, where there's a lot happening. With drivers and transducers constantly evolving, innovations are happening not only in design, construction, and materials but also in the engineering approach. This expanded report throws light on key areas of innovation for speaker technologies, from new magnetic materials to acoustic metamaterials and advanced processes, anticipating the next five years (at least) for the loudspeaker industry.Following up on the topic of Speakers, audioXpress is honored to publish an article by Charlie Hughes (Principal Engineer, Electroacoustics at Biamp) sharing "Best Practices for Loudspeaker Equalization and Tuning." Charlie Hughes has been involved in pro audio for more than 30 years, received the CTA Technology Achievement Award for his standards work, holds multiple patents relating to loudspeaker design, and knows a thing or two about directivity control and how a loudspeaker system should sound good and measure accordingly. This article offers basic recommended guidelines that will not only help to develop good equalization and tuning practices, but also will go a long way in improving the overall sound quality, regardless of the application.
audioXpress readers always appreciate a good book review in any topic related with audio, and that's precisely what Scott Dorsey brings us in this issue. Dan Alexander Audio: A Vintage Odyssey is a compilation of memories and notes from the experienced musician, producer, and audio equipment collector and trader who coined the phrase “vintage recording equipment,” as an extension of his activities as a “vintage” guitar dealer. Dan Alexander began buying and selling used guitars in 1967 at the age of 17, built and bought recording studios, sold hundreds of Neve mixing consoles and thousands of tube microphones. As Scott Dorsey says, "...plenty of other people out there (...) were also responsible for a big part of the vintage gear craze, but they didn’t write books about it and Dan Alexander did."
From speakers and microspeakers, to in-ear drivers, this edition includes a great review article by Brent Butterworth, about the Olive Pro Hearing and Bluetooth Earbuds that were recently brought to market by Olive Union. These are 2-in-1 true wireless earbuds and smart (FDA-Registered class II) hearing aids, featuring a modern design that was intentionally conceived to look like futuristic Bluetooth earbuds to combat the social and economic barriers of hearing loss. Approaching the concept with a similar procedure to his previous product reviews of advanced hearing assistance products, Brent Butterworth was confronted with the announcement that the company had temporarily paused its sales efforts in the US. Having tested the product and understanding the approach, he then talked with the company to find out what happened and their plans to adjust and return to market. The result is an even more engaging story for audioXpress readers interested in over-the-counter (OTC) hearing-aids and this promising application field.
And related to the development of in-ear designs, this issue also features an article by Raj Senguttuvan (Knowles Corp.) discussing design differentiation for True Wireless Stereo (TWS) earbuds development. The article details the opportunities for manufacturers to differentiate by leveraging the possibilities of the latest Knowles development kit centered on the capabilities of its AISonic family of audio edge-AI processors, expanded by key partnerships in voice and audio processing algorithms for TWS products. The Knowles development kit for TWS earbuds combines the company's microphone arrays, balanced armatures, bone conduction sensors, and AISonic processors, paired with a codec that provides integrated hybrid noise cancelling, AFE, ADC, DAC, and filters, and a premium Bluetooth Audio System-on-Chip (SoC).
Diving further into audio electronics, this issue includes the second part of an article by Frans de Wit, "Thinking about DC Power Supplies." This is a great read for anyone interested in high-quality audio circuits and in need of a high-quality low-power "power source." Following an introduction to multiple circuit types suitable for high-quality audio designs in the first part of the article, the author now offers considerations on seven circuits for electronic DC power supplies. And those interested can explore further by downloading the LTspice files available in the Supplementary Materials section of the audioXpress website.
In this month's Sound Control column, Richard Honeycutt discusses the problems that both acousticians and sound engineers face with intelligibility perception and related complaints of “I can’t hear what they’re saying!” In a personal testimony of countless situations of this type, Richard Honeycutt shares how to interpret what users complain about with the associated real causes and solutions. A great introduction to real and perceived issues, before exploring measuring methods for quantifying them.
And for those readers who have been curious about the resurgence of vinyl, Mike Harkins, an experienced professional with a career devoted to quality, reliability, and manufacturability of products, proposes an interesting project. Being a music aficionado long devoted to vinyl, he wanted to learn how good are today's audiophile vinyl records, particularly those expensive vinyl 180-gram or 200-gram pressings and limited editions. In "An Experience with High Quality Vinyl" Mike Harkins sampled a mix of very high-quality pressings of albums he ordered online, and even a Limited Edition direct-to-disc recording, in an effort to learn if these are "as good as has ever been pressed." Read the article to see the statistics and conclusions.
For our readers looking for an interesting DIY project, our veteran speaker builder Ken Bird ventured into omnidirectional territory with a twist. He proposes a floorstanding speaker design that relies on its four sides, based on a concept devised by the late David B. Weems, using eight drivers. The OMNI Tower VII project features two piezo tweeters, four midrange drivers - one per side of the enclosure - plus two woofers on a separate chamber. A great-looking project that is certain to generate an impression.audioXpress is published 12 times per year, and available in print and online. Subscribing to the digital online version allows immediate access and is available here: www.audioxpress.com/page/audioXpress-Subscription-Services.html
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