All items in category Magazine Articles
Diagnosing Design Issues Using the Klippel Distortion Analyzer
by Patrick Turnmire

Diagnosing Design Issues Using the Klippel Distortion Analyzer

The founder and principal of Redrock Acoustics, renowned for offering engineering and design services, Patrick Turnmire has tested thousands of driver samples during his career, including countless for Voice Coil's Test Bench. Having recently reopened access to its Klippel testing and transducer analysis services, Turnmire shares his vast experience, advising on how to make sure the tests are robust enough to clearly see the loudspeaker performance.
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Simulation Techniques: Room Gain
by René Christensen

Simulation Techniques: Room Gain

Room Gain is a term not used in acoustics textbooks as such. Room acoustics is naturally often discussed in the hifi community, since the room you put your loudspeakers in will heavily influence the sound that reaches your ears, both at low and high frequencies. In these discussions the term "room gain" sometimes comes up. This article was inspired by Erik Wiederholtz (CTO of Perlisten Audio) and his interest in the topic, and he was kind enough to provide measurements and photos from his own listening room for a sealed subwoofer as well as for a vented subwoofer.
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Simulation Techniques: Acoustic Topology Optimization for Vibroacoustics Applications
by René Christensen

Simulation Techniques: Acoustic Topology Optimization for Vibroacoustics Applications

Acoustic topology optimization is one of the most interesting new technologies in vibroacoustics. These powerful tools enable engineers to find optimal solutions to problems related to their specific applications and this article presents multiple examples in different areas. The article, originally published in audioXpress, April 2023, includes several examples of transducer geometries modified via acoustic topology optimization.
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A Look Inside Douglas Self’s "Small Signal Audio Design" 4th edition
by Jan Didden

A Look Inside Douglas Self’s "Small Signal Audio Design" 4th edition

Whether it is power amplifiers, vinyl reproduction preamplifiers, active crossover filters or, as in this case, small-signal circuits for a very wide range of applications, Douglas Self is one of those authors who consistently has produced reference works about technical audio. You may think that as a fourth edition, it would just be a refinement on the three editions that went before it but Self always adds new material and new insights to make it worthwhile to get this new book.
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Low Frequency in Loudspeakers: It’s All About the Bass!
by Mike Klasco

Low Frequency in Loudspeakers: It’s All About the Bass!

All the speaker design techniques to achieve more bass, challenging Hofmann's Iron Law. The same bass in a smaller enclosure? Deeper or louder bass for the same enclosure back volume? Higher efficiency for a given alignment? A cleaner lower distortion bass? Learn about the companies, products, and technologies that make all this possible. This article was originally published in Voice Coil, November 2023.
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Simulation Techniques: Lumped Element Modeling of Transducers
by René Christensen

Simulation Techniques: Lumped Element Modeling of Transducers

An exploration of the possibilities for product development focusing on modeling of transducers. As many engineering tasks require a common ground from which discussions among those involved in a project can take place in a structured manner, this often involves a so-called model of the concept or product. This article discusses one such model: the lumped element model. This article was originally published in audioXpress, March 2023.
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Voice Coil Patent Review: Controlled Passive Radiator
by James Croft

Voice Coil Patent Review: Controlled Passive Radiator

James Croft has fun reviewing a Controlled Passive Radiator patent awarded to inventor Tony Doy, on behalf of Sonos (Santa Barbara, CA.) The patent details multiple techniques to control a passive radiator, including a device buffering successive samples of audio content and predictive techniques on active designs. With this extensive review, Voice Coil readers will gain a valuable perspective on key possible innovation areas. This article was originally published in Voice Coil, October 2018.
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Bass Reflex Performance Envelope - Part 3: A Practical Example
by Gary Gesellchen

Bass Reflex Performance Envelope - Part 3: A Practical Example

In this article, Gary Gesellchen (Vanatoo) completes his Bass Reflex Performance Envelope exploration. After concluding the main analysis portion of the article determining his novel approach to estimating the performance envelope available from bass reflex loudspeakers, Part 3 shows an example to see how his calculations all work together, and addresses some practical considerations. This article was originally published in audioXpress, September 2023.
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Patent Review: Dual Coil Electrodynamic Transducer with Channels for Voice Coil Cooling
by James Croft

Patent Review: Dual Coil Electrodynamic Transducer with Channels for Voice Coil Cooling

James Croft reviews a published design submitted on behalf of Harman International Industries on January 2017. The design details an important approach to solving the everlasting problems of heat generation that limits the power handling capacity and the distortion-free acoustic output capability of loudspeakers, as well as their efficiency as electroacoustical transducers. This article was originally published in Voice Coil, September 2018.​​​​​​​
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Bass Reflex Performance Envelope - Part 2: System Analysis
by Gary Gesellchen

Bass Reflex Performance Envelope - Part 2: System Analysis

This Bass Reflex Performance Envelope article series describes a novel approach to estimating the performance envelope available from ported loudspeakers. Part 2 expands on the system analysis, showing how driver and port sizes determine how loud and how low a system will play, and how that relates to generally available drivers. This article was originally published in audioXpress, August 2023.
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