Listen, Test, and Measure It! audioXpress March 2020 Now Available.

audioXpress continues its mission to serve the audio engineering and audio development communities with its Test & Measurement Focus edition. For the March 2020 edition, we prepared a special Market Update highlighting the latest solutions that are available to the audio industry, including updates to some of the most established measurement toolkits. All the products and solutions selected for this Test & Measurement Market Update have been introduced in the last 12 months and address specific market requirements for all types of signal and acoustical measurements, research and development, repeatable processes for quality control, high-speed production tests, and troubleshooting at the test bench.

Among this edition's feature articles, Dan Knighten (vice-president of product development for Audio Precision), discusses "Strategies for Optimizing Audio Production Tests." This practical Test & Measurement article focuses on several key challenges found in the production of audio products and shares strategies for optimizing the measurement system to address said challenges. Included in the discussion are test time and device throughput, test process control, and repeatability, cost-of-test, and the use of reference devices (so-called "golden units"). The advantages of a common test platform (across R&D and Manufacturing) are also addressed.

After a decade of widespread use, the Dayton Audio Test System (DATS) has acquired an impressive reputation for fast and accurate testing. Now, Dayton Audio has taken the easy-to-use audio test system and improved it in almost every way when creating the DATS V3 Computer-Based Audio Component Test System. In this edition of audioXpress, David Logvin offers a detailed review of this must-have tool for the speaker builder and a very valuable tool for anyone who regularly works with audio equipment.

In another of this month's features, Luke McCready shares what he learned about the fantastic Audeze Mobius Headphones, a clear departure from the usual mold for the California high-end planar magnetic headphone manufacturer. The Mobius are wireless Bluetooth headphones capable of LDAC high-resolution playback and virtualized surround sound, as well as a sophisticated platform to which Audeze keeps adding a number of surprises. In this extensive review, McCready explores what this headphone can do, the use-cases for its unique features, and the limitations of this boldly conceived product.

In this month's Audio Scope column, Michael Steffes dives further into the intrinsic advantages of using the newest low-power fully differential amplifiers (FDAs) to interface measurement mics to 24-bit delta-sigma ADCs. This month he discusses added operational constraints and some of the error terms to consider once the AC input coupled mic signal is available as a differential DC coupled output to the ADC. He also introduces an alternate filter design.

For this month's Sound Control column, Richard Honeycutt discusses how to better capture choirs with orchestras or an organ. In the February 2019 Sound Control article, Richard addressed the issue of miking choirs for recording, broadcast, and live sound reinforcement. The challenges of obtaining a good pickup of instrumental accompaniment, including piano, organ, and orchestra was not discussed, and is now the topic of this article.

And, this edition concludes with the second article on "Powering Audio Circuits." After reviewing battery power in Part 1, Ed Simon now tackles all aspects in AC power supplies, starting with transformers. As he explains, converting the alternating current (AC) power line into useful lower voltage direct current (DC) is the second most popular method of powering sound equipment, and the easiest method to safely do this is with a transformer-based linear power supply. Read on.

The March 2020 edition of audioXpress is now available online, and on its way to those who subscribe to the print edition. To read this edition now, you will need to subscribe to audioXpress. Print and/or Digital subscriptions are available. Subscribe to the digital online version and get immediate access at: 
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