All items in category Magazine Articles
R&D Stories: Developing an Electrostatic Transducer
by Comsol Multiphysics

R&D Stories: Developing an Electrostatic Transducer

This article discusses how Warwick Audio Technologies designed a completely new type of transducer for high-end electrostatic headphones using the latest materials, validated with computer simulation tools from Comsol. The design process for the High-Precision Electrostatic Laminate (HPEL) transducer was first available in the outstanding Sonoma Model One, the world’s first headphones to use HPEL audio transducers, and all subsequent Warwick products, now expanding also to automotive applications. This article was originally published in audioXpress, April 2018.
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Patent Review: Acoustic Resistive Elements for Ported Transducer Enclosure
by James Croft

Patent Review: Acoustic Resistive Elements for Ported Transducer Enclosure

This review highlights a patent granted to Bose Corp, part of an interesting series of bass reflex and tuned pipe enclosure architectures explored by Bose, which James Croft reviews and explains in detail. The patent describes a single chamber, single tuned, bass reflex enclosure system, using a more advanced, single Helmholtz tuned bass reflex design, with a port that is folded and extended. A great patent review with lots of informative details. This article was originally published in Voice Coil, October 2017.
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Patent Review: Simply A Speaker by Harman
by James Croft

Patent Review: Simply A Speaker by Harman

This review looks at a speaker patent, awarded to inventor Shengbo Li from Guangdong, China, on behalf of Harman International. The abstract from that patent details a speaker including one or multiple transducers, an enclosure, and a suspension mounted on the enclosure, wherein the suspension and the enclosure are configured such that the enclosure is capable of vibrating as a result of operation of the transducer so as to produce audible sound. You read it right, the enclosure is also a passive radiator!
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Patent Review: Bass-Reflex Speaker Cabinet Having a Recessed Port
by James Croft

Patent Review: Bass-Reflex Speaker Cabinet Having a Recessed Port

This patent awarded to inventor Matthias Larrieu, on behalf of French company NEXO (owned by Yamaha Corp.) was the topic of this detailed review by James Croft. From the abstract it might be difficult to visualize what exactly differentiates the patented design from a standard bass reflex system. Basically, Larrieu created two V-shaped slices at the opening either centered or with one at each side of the port, helping to reduce amplitude and phase anomalies in the midrange due to port resonances, while improving mid-band directivity.
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Remote Recording in the Rock Era: David Hewitt’s On the Road
by Scott Dorsey

Remote Recording in the Rock Era: David Hewitt’s On the Road

For an enjoyable suggestion, after you finish reading audioXpress, Scott Dorsey reviewed an interesting book written by David Hewitt, one of the many well-known engineers who made history doing live recordings of rock concerts during the 1970s and 1980s - and continued to pioneer this approach to make great recordings of live events. On the Road: Recording the Stars in a Golden Era of Live Music, is an interesting first person testimony of some of the greatest moments in music recording history. This article was originally published in audioXpress, April 2023.
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Practical Test & Measurement: REST for Automated Test and Measurement
by Matt Taylor

Practical Test & Measurement: REST for Automated Test and Measurement

This article is a great introduction to the use of web interfaces, and embracing 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. Written by the founder of Seattle, WA-based QuantAsylum, this contributed piece advocates an open-design philosophy for controlling and querying things via REST, and leveraging the know-how of millions of developers. This article was originally published in audioXpress, March 2022.
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Patent Review: Rotary Transducer with Improved High-Frequency Output
by James Croft

Patent Review: Rotary Transducer with Improved High-Frequency Output

This article examines an important patent filed in 2014 by F. Bruce Thigpen (Tallahassee, FL) and granted in June 2016. Appearing both as the inventor and assignee, Thigpen describes a rotary sound transducer having an improved output at higher frequencies. Thigpen has been working on this type of device for more than a decade and has advanced what was already a very difficult engineering achievement, to a more sophisticated structure that apparently raises the general performance and high frequency limits beyond what was thought possible with this architecture. This article was originally published in Voice Coil, July 2017.
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Practical Test & Measurement: Transitioning Audio Tests from R&D to the Production Line
by Steve Temme

Practical Test & Measurement: Transitioning Audio Tests from R&D to the Production Line

Production line audio testing poses many challenges such as noisy environments, harsh operating conditions, high throughput, relative limits, and more. In this article, Steve Temme, the founder and President of Listen, writes about the essentials of test and measurement applied to manufacturing environments and quality control. Production tests always benefits from proven practices and experience and that's what is shared in this article, outlining the main considerations to ensure a successful operation. This article was originally published in audioXpress, March 2023.
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Practical Test & Measurement: The Proof Is in the Testing
by Adran Lara Moreno and Christian Bellmann

Practical Test & Measurement: The Proof Is in the Testing

The Klippel Near Field Scanner System (NFS) was used for the critical testing and measurement of Holoplot's X1 Matrix Array compensation algorithm capabilities. All our readers who have appreciated the story of the development of the unique Holoplot technology, published in the September 2022 issue of audioXpress, will enjoy reading about how Klippel and Holoplot worked to overcome frequency absorption and gain reduction challenges that resulted from the need to conceal the X1 systems behind an acoustically semi-transparent projection panel.
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Fresh From the Bench: Echo AIO - A Cost-Effective Audio Test System
by Stuart Yaniger

Fresh From the Bench: Echo AIO - A Cost-Effective Audio Test System

Headquartered in Santa Barbara, CA, Echo Test + Measurement is a little company with a big impact on audio test and measurement. As many large consumer electronics companies started using its AudioFire studio sound cards for production line testing, Echo designed a highly cost-effective, modular range of USB-based audio test interface solutions, which Stuart Yaniger had the opportunity to evaluate. He completed a series of tests and shares his experiences with the new Echo AIO modular audio test system.
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