All items in category Theory Articles
Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 4
by Andy Lewis

Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 4

In this final article of the four-part series, Andy Lewis expands upon the Back EMF concepts hinted at in the previous three articles in this series. This article explores the Electrical and Newtonian filters and their intersections, observations on reactive parallel filters as pertains to Back EMF and energy losses. The theories can be applied to virtually all areas of loudspeaker design. This article was originally published in audioXpress, November 2018.
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Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 3
by Andy Lewis

Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 3

In the third article of the four-part series, Andy Lewis continues his fascinating exploration of Back EMF Phase Relationships in Moving-Coil Loudspeakers. The author discusses what causes Back EMF to simulate inductor, capacitor, or resistor (LCR) components, and explores the concept of slip, in order to explain how and why it causes the impedance to be inductive, resistive, or capacitive, depending on frequency. This article was originally published in audioXpress, July 2018
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Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 2
by Andy Lewis

Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 2

In this article series, Andy Lewis explores the generation of Back EMF in the region of a loudspeaker’s resonance. In this second article of the four-part series, he performs simple “thought experiments” to make qualitative observations about the activity of a moving-coil driver in the region of its resonance. This article was originally published in audioXpress, June 2018
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Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 1
by Andy Lewis

Back EMF Phase Relationships in Moving-Coil Loudspeakers - Part 1

In this article, Andy Lewis explores the generation of Back EMF in the region of a loudspeaker’s resonance. He also demonstrates a method for calculating the position of the moving assembly (or “cone”) relative to input signal, using complex impedance measurements. This article - part of a four part series - was originally published in audioXpress, May 2018
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Disc Recording Equalization Demystified
by Gary Galo

Disc Recording Equalization Demystified

This article explains the methods of cutting disc records, the characteristics of magnetic phono cartridges, and how their combined response determines the required playback equalization. The article is based on a paper the author presented at the May 1996 conference of the Association for Recorded Sound Collections (ARSC) in Kansas City, and was first published in the Fall 1996 issue of the ARSC Journal. Later, the article was featured as part of "The LP Is Back!" compilation book published in 1999 by The Audio Amateur company.
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Updating the Rules on Amplifier Metrics
by Jens Tybo Jensen

Updating the Rules on Amplifier Metrics

This article shares a new important insight on modern Class-D amplification from the experienced perspective of Jens Tybo Jensen - part of the founding team at Merus Audio, and now head of Class D Audio Marketing and Applications at Infineon. The author states that it may be time to rethink Class D audio design and measurement practices, and he details what multilevel Class D amplification can do for new product designs. This article was originally published in audioXpress, October 2019.
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Loudspeakers for Vented Enclosures: A Backward Approach for Speaker Selection (LoVE BASS)
by Francisco Castells

Loudspeakers for Vented Enclosures: A Backward Approach for Speaker Selection (LoVE BASS)

In this article for Voice Coil, the authors explore the problem of designing vented enclosures, describing a backward concept they call LoVE BASS, which they found to save a substantial amount of engineering hours during the process of speaker box design. As opposed to taking a given driver and designing an enclosure, the authors define the system’s target performance in terms of physical volume, lower cut-off frequency, ripple and maximum achievable SPL, after which they look for candidate drivers that allow for such a design. This article was originally published in Voice Coil, July 2019.
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Electroacoustic Measurements of Headphones
by Christopher J. Struck

Electroacoustic Measurements of Headphones

Christopher J. Struck (CJS Labs) discusses all options available for headphone testing and calibration. The article discusses what should be included in a complete headphone test system, considerations on electrical impedance, considerations on repeatability of the results, free and diffuse field corrected responses, left-right tracking, and the use of two-tone distortion measurements. Reference reading material. This article was originally published in Voice Coil, July 2019.
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Why Doesn’t My Stereo Sound Like a Live Concert?
by Ethan Winer

Why Doesn’t My Stereo Sound Like a Live Concert?

In this article for audioXpress, "Why Doesn’t My Stereo Sound Like a Live Concert?", Ethan Winer explains why acoustics matter and why the fidelity of your audio devices and speakers is not the reason your hi-fi doesn’t make your living room sound like you’re hearing a concert in a concert hall. This article was originally published in audioXpress, August 2019.
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Klippel Controlled Sound (KCS) - Controlled Sound Technology for Nonlinear Compensation of Loudspeakers
by Vance Dickason

Klippel Controlled Sound (KCS) - Controlled Sound Technology for Nonlinear Compensation of Loudspeakers

Following extensive research, Klippel GmbH has announced its new Klippel Controlled Sound (KCS) technology. This is an integrated approach that leverages the company's software and hardware tools for development, measurement and evaluation of new-generation loudspeaker systems, providing mechanical and thermal protection, automatic system alignment, active compensation of transducer nonlinearities and stabilization of the voice coil rest position. In other words, enabling research towards the speakers of the future.
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