All items in category Theory Articles
Voice Coil Lab Notes: Phase, Group Delay, and Impulse Response - A Quick Primer
by Christopher J. Struck

Voice Coil Lab Notes: Phase, Group Delay, and Impulse Response - A Quick Primer

This short article by Chris Struck (CJS Labs) is mainly focused on the definition and interpretation of phase, helping to make sense of complex data. This reference article is an expanded version of a previous Lab Note published by CJS Labs, and is certainly a great summary of essential knowledge in speaker design. This article was originally published in Voice Coil, December 2020.
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Better Microspeakers Utilizing Hiperco Alloys
by Aminul Md Mehedi

Better Microspeakers Utilizing Hiperco Alloys

This Voice Coil Spotlight article by Aminul Md Mehedi (Senior Application Development Engineer at Carpenter Technology Corp.) explains how the Carpenter-developed high-performance Hiperco 50 and Hiperco 27 soft magnetic alloys can contribute to better performing microspeakers and earphone drivers, improving "decibel (dB) density" in miniaturized consumer electronic devices. This article was originally published in Voice Coil, November 2020.
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The Capacitance Multiplier
by Bill Reeve

The Capacitance Multiplier

In this article for audioXpress, Bill Reeve helps us to make sense of a misunderstood circuit. A capacitance multiplier is useful as a power supply low-pass filter. It is commonly said that, like Miller capacitance, the capacitor’s value in this circuit is “multiplied” by the transistor gain (β) to lower the filter’s pole frequency. The transistor-enhanced filter does that and more, as the article explains in detail. This article, an excellent tutorial on analog circuit design, was originally published in audioXpress, August 2012.
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Searching for a Unicorn Part 2: Generating a Good Signal Source
by Brian Lowe

Searching for a Unicorn Part 2: Generating a Good Signal Source

In this second article, Brian Lowe (Belleson LLC) continues his search for the Unicorn of "Measuring Voltage Regulator Ripple Rejection," this time focusing on the test fixtures. Testing a voltage regulator with exceptionally good performance requires an even more exceptional signal source and measurement setup to measure sub-microVolt ripple across a wide frequency range. Complementing the final article, Jan Didden, offers an informative sidebar about super regulators. This article was originally published in audioXpress, June 2019.
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Searching for a Unicorn Part 1: Measuring Voltage Regulator Ripple Rejection
by Brian Lowe

Searching for a Unicorn Part 1: Measuring Voltage Regulator Ripple Rejection

In this article Brian Lowe shares a fascinating journey in his search for a "Unicorn" that is measuring voltage regulator ripple rejection - or power supply rejection ratio (PSRR). Lowe is the founder and principle engineer at Belleson, LLC, and he has devoted a lot of time to this fascinating "quest." This article was originally published in audioXpress, May 2019.
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Practical Test & Measurement: Mastering Wireless Multi-Tone Testing
by Andrew Taylor

Practical Test & Measurement: Mastering Wireless Multi-Tone Testing

This article explains the issues resulting from measuring a wireless audio connection and how wireless multi-tone testing can help us to overcome those obstacles. The article is particularly focused on the needs of manufacturers and designers of modern wireless audio devices and offers valuable insights on multi-tone testing, a technique that has been around for many years, and which Klippel perfected in its own multi-tone measurement module (MTON). This article was originally published in audioXpress, December 2020.
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Practical Test & Measurement: What to Measure for Quality Control of Audio Devices
by Dan Knighten

Practical Test & Measurement: What to Measure for Quality Control of Audio Devices

In this Test & Measurement article from Dan Knighten (Audio Precision), the author focuses on the practical question of manufacturing test strategies and objectives and shares what measurements reveal about the device under test, offers suggestions for specific measurements, and provides techniques for various devices and scenarios. This article was originally published in audioXpress, November 2020.
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Communications: Testing and Optimizing Strategies for Conference Terminal Equipment
by Hans W. Gierlich

Communications: Testing and Optimizing Strategies for Conference Terminal Equipment

Following up on the two Communication articles published in audioXpress October 2020, Hans W. Gierlich, from HEAD acoustics GmbH, a top expert in his field, contributed this great overview article. With most company employees working from home and the trend toward decentralized organizations and remote collaborations, where webinar and conferencing services are the new way of communication, this a timely topic. This article was originally published in audioXpress, November 2020.
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Thin-Film High-Frequency Transducers (Part 2) - The LT2/LT6 Ribbon Transducers
by Igor Levitsky

Thin-Film High-Frequency Transducers (Part 2) - The LT2/LT6 Ribbon Transducers

In its August 2020 edition, Voice Coil featured an article by experienced speaker designer Igor Levitsky on The Advantages of Thin-Film High-Frequency Transducers. In a follow-up Spotlight article the author returns to expand on the development and design aspects of the Radian Audio LT2/LT6 Ribbon Planar transducers - its more recent, commercially available project, in which he continues to be involved. This article was originally published in Voice Coil, September 2020.
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Thin-Film High-Frequency Transducers (Part 1) - The Advantages
by Igor Levitsky

Thin-Film High-Frequency Transducers (Part 1) - The Advantages

In its August 2020 edition, Voice Coil featured an article by experienced speaker designer Igor Levitsky, highly recognized in the industry for developing some of the best planar magnetic speaker and headphone drivers for some of the most reputed brands, focusing precisely on this type of technology. It seems clear that we will see more and more headphones and speakers using thin-film drivers, as the industry is now perfecting the use of different types of diaphragms and materials. The August 2020 edition of Voice Coil includes the first part of this article, completed in the September 2020 edition.
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