As a long-standing tradition and one of our most popular topics, our Test and Measurement issue addresses the latest tools and solutions meeting real-world challenges in audio. audioXpress March 2022 includes an extensive Market Update report, reviewing the audio test and measurement market segment and trends, including recent mergers and acquisitions. The feature article highlights all the new audio test and measurement products and solutions released during the past 12 months. Discover products and solutions from HEAD acoustics, Audio Precision, GRAS Sound & Vibration, NTi Audio, Klippel, Listen, Echo Test + Measurement, Outline, QuantAsylum, ZUMI Systems, and even Bluetooth LE Audio capture and analysis solutions from Ellisys.
Adding a great perspective on the topic of test and measurement, in particular for production lines, our good friend Matt Taylor, wrote an introduction to the use of REST for Automated Test and Measurement. His article makes the case for using web interfaces, and embrace web standards for automated testing of audio equipment, fundamentally exploring the possibilities of REST - which stands for Representational State Transfer, a widely accepted set of guidelines for creating reliable web APIs. Our readers will recognize Matt from his Seattle, WA-based company QuantAsylum, but this contributed piece advocates an open-design philosophy for controlling and querying things via REST, and leveraging the know-how of millions of developers. As Matt says, "Instead of needing an engineer that knows how to write GPIB or LabVIEW - a fairly specialized set of skills - you can use an engineer who knows how to code web apps. And how cool is that!"
Complementing the topic of Audio Test and Measurement, Joe Begin (Audio Precision) wrote an article that addresses the practical approach to test and evaluate multichannel MEMS microphone arrays. The simultaneous acquisition and measurement of signals from a microphone array presents a variety of challenges to developers seeking to evaluate their designs. This article explains the fundamentals to address challenges in smartphones, smart speakers, and all sorts of voice-activated devices, typically using two, and up to seven or more microphones.
Featured on this month's cover is also our extended review of KEF's tiny but giant-sounding KC62 subwoofer. Oliver Masciarotte and Kent Peterson, the fantastic duo who recently reviewed the KEF LS50 Meta speakers for audioXpress, have now extended their analysis with a detailed review of the KC62 compact subwoofer, which combines KEF's force-canceling and Uni-Core technologies in a new approach to allow maximizing bass in a minimum space. Masciarotte did the listening and spoke with Jack Sharkey, Senior Technical Engineer at GP Acoustics, about this fascinating design. For this review, the KEF KC62 subwoofer was measured by Peterson at Warkwyn’s facility using the Klippel measurement system.
For those looking into a practical DIY project, Ben Chen (Sfera Labs) proposes a Sound Level Evaluation solution based on the popular Raspberry Pi 4. His article details the possibilities of using the Sfera Labs' Exo Sense Pi - a compact multi-sensor module with a Raspberry Pi 4 - as a sound meter. The author illustrates the main concepts involved, and possible software applications for sound level evaluation. The Exo Sense Pi combines several environmental sensors and connectivity options, and integrates a digital microphone which can be used to evaluate ambient noise levels or measuring noise sources.
And for his Sound Control article, Richard Honeycutt writes precisely about the topic of Sound Levels - How Loud Is It? As he details, over the years, how our perception of loudness has changed and while sound can be measured in many different ways, we must be sensitive to what is the proper sound level for all concerned, not just what is possible. In his article, he discusses some of the loudest sound sources and what factors influence an audience’s perception of the proper loudness.
Bonus Digital Content!
Extending the March 2022 issue and expanding on topics covered in previous editions, the online edition of audioXpress features a complete Market Update on Voice Capture and Voice Interface Systems - an area of great activity on past months. In this article, audioXpress looks at all the latest voice front-end solutions, from miniature ECMs to MEMS microphones to complete voice front-ends for voice recognition and voice interface applications. A great overview of the latest key technology components that are available for the development of voice solutions in multiple application fields.
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