All items in category Magazine Articles
Development & Design: The Impact of Microphone Specifications on Active Noise Cancellation Performance
by Nikolay Skovorodnikov

Development & Design: The Impact of Microphone Specifications on Active Noise Cancellation Performance

Active noise cancellation (ANC) is a popular feature for consumer electronics headsets, headphones, and earbuds. Designing effective ANC imposes particular specification requirements on audio chain components, including microphones. This article explains how to achieve better true wireless stereo ANC designs, offering valuable insights for this trending application.
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Patent Review: Acoustic Transducer Comprising a Plurality of Coaxially Arranged Diaphragms
by James Croft

Patent Review: Acoustic Transducer Comprising a Plurality of Coaxially Arranged Diaphragms

This is a review of a design patent, submitted on behalf of Tymphany, trying to address the shortcomings of the work of Dr. Oskar Heil with his Air Motion Transformer (AMT) woofer system. The patent describes an acoustic transducer comprising one or more electromagnetic motors that drive one or more sets of multiple diaphragms to provide acoustically efficient loudspeaker systems in compact dimensions.
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R&D Stories: How Optical Technology Enables a Generational Shift in MEMS Microphone Performance
by Jakob Vennerød and Kieran Harney

R&D Stories: How Optical Technology Enables a Generational Shift in MEMS Microphone Performance

The article summarizes the evolution of MEMS microphone technology and describes the benefits of optical microphones over conventional solutions. This is a crucial reading to understand how the first generation of optical MEMS microphones have smashed the limits of SNR and dynamic range of miniature microphones, with 80dBA SNR (14dBA noise floor), 132dB dynamic range, 24-bit digital output and all with ultra-low power consumption.
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R&D Stories: Motion Feedback for Active Desktop Subwoofers
by Zami Schwartzman

R&D Stories: Motion Feedback for Active Desktop Subwoofers

Zami Schwartzman, the founder of Servobass, shares his journey into the application of Motion Feedback (MFB) methods for active subwoofers. He explores passive and active bass enhancement methods and how Servobass arrived at an optimized design using MFB techniques to achieve highly performing active subwoofers in desktop and compact sizes. A solution that is now available to be licensed by the industry. This article was originally published in audioXpress, November 2023.
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Getting to Know Dutch & Dutch
by Jan Didden

Getting to Know Dutch & Dutch

With a visit to Dutch & Dutch, Jan Didden unveils the journey of this innovative speaker manufacturer from The Netherlands. This company, founded in 2014, has so far achieved remarkable success with a single product designed to break the vicious cycle of speakers and room acoustics. The Dutch & Dutch 8c is a no-compromise active speaker designed to work together with the acoustics of the listening room.
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No Zipper, No Pop! How ADC Hybrid Gain Control Can Enable Smooth, Pop-Free Microphone Preamp Gain Changes
by Michael Chandler-Page

No Zipper, No Pop! How ADC Hybrid Gain Control Can Enable Smooth, Pop-Free Microphone Preamp Gain Changes

This article explains the new hybrid gain control (HGC) feature of Cirrus Logic’s latest CS530xP family of Pro Audio ADCs and how these can eliminate noise problems when changing gain on digitally controlled mic preamps. This solution enables fine-resolution mic preamp gain control, with the feel of a traditional potentiometer but without audible pops or zipper noise by integrating control into the ADC, together with zero-cross detection and precisely synchronized digital gain control.
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The AudioChiemgau ModeCompensator: A Quick Basic Test
by Rens Tellers

The AudioChiemgau ModeCompensator: A Quick Basic Test

The principles applied by Dr. Reinhold Lutz's for precise measurement of the sound pressure frequency response in the presence of room modes, are available in its AudioChiemgau Mode-Compensator solution. Jan Didden and Rens Tellers did a basic functional test to find out how well they could make it work and they were pleasantly surprised with the results. This article was originally published in audioXpress, October 2023.
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Measuring Loudspeaker SPL Response and Harmonic Distortion at Low Frequencies
by Reinhold Lutz

Measuring Loudspeaker SPL Response and Harmonic Distortion at Low Frequencies

This article discusses how to measure loudspeaker SPL response and harmonic distortion at low frequencies in a standard environment, full of reflections from acoustically hard boundaries (e.g., walls, floor, and ceiling), room resonances, and even ambient noise reducing the dynamic range and accuracy of the measurements. The method combines near-field measurements with two identical microphones. This article was originally published in audioXpress, October 2023.
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Patent Review: Self-Bias Emitter Circuit
by James Croft

Patent Review: Self-Bias Emitter Circuit

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.
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Patent Review: Smart Bass Reflex Loudspeaker
by James Croft

Patent Review: Smart Bass Reflex Loudspeaker

James Croft (Croft Acoustical) reviews a very curious patent from Amazon Technologies, Inc. (Reno, NV), filed in 2013, and awarded in April 2017. Basically, the patent discusses a new technique to tune a port of a loudspeaker, in this case multiple ports that will be open or selectively closed, in function of an analysis of the frequencies of the signal being played. This article was originally published in Voice Coil, June 2018.
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