Advanced Test Methods for Improving ANC Headphone Performance

From speaker practice and theory, this article on advanced test methods for improving Active Noise Cancellation (ANC) headphone performance attempts to gain better data to draw stronger conclusions about the ANC performance and is a must-read for product developers and anyone interesting in learning how to evaluate those systems. This article was originally published in audioXpress, October 2018.

With the availability of low-cost, PC-based acoustic data acquisition systems, experienced hobbyists can make highly accurate loudspeaker frequency-response measurements without an anechoic chamber. The power of these systems comes at a price. These systems window the time-domain measurement to eliminate room reflections. This, in turn, limits low-frequency response. This article was originally published in audioXpress, June 2012.

Recently, the very existence of current feedback as opposed to voltage feedback has been called into question. This article analyzes and tests simple versions of voltage and current feedback amplifiers and demonstrates some differences in their characteristics. The article provides an excellent overview of historical terminology and how the more modern terms came about and their dependence on context. These articles were originally published in audioXpress, July and August 2018.

On the cutting-edge of current audio industry trends, this article by Jon Schorah explains what you should know about delivering music to Spotify, Apple Music, TIDAL, and other platforms. Jon Schorah explains how to deal with different audio codecs, the effects of masking, Spectral Band Replication (SBS), Parametric Stereo (PS) and others way these services deal with data rate reduction, as well as loudness normalization. This article was originally published in audioXpress, June 2018.

audioXpress readers are well familiarized with Richard Honeycutt's Hollow State column. In many of his articles, Honeycutt explored distortion in a quest to find the origin of “tube sound.” In this article, he takes a more general view of possible amplifier differences, solid- or hollow-state, focusing on different amplifiers’s differences in sounds, and a correct subjective evaluation process of components and systems. This article was originally published in audioXpress, October 2012.

Because every R&D department in the planet is currently looking at implementing voice, and everyone's looking at audioXpress for guidance on how to design a smart speaker, in this edition Kevin Connor, shares his insider knowledge on the topic. Connor, a Cirrus Logic engineer, explains how to provide audio and voice solutions, and design products that sound great and respond reliably to voice commands, regardless of backend service. This article was originally published in audioXpress, January 2018.

In order to generate a sound, a driver must vibrate. But what happens when one or more drivers are placed on the same baffle? In the exact moment that the cone begins to move, it starts to transmit — through the frame and the screws — vibrations to the cabinet and to the other drivers that are fixed on it. This article discusses multiples approaches to handle the problem, working on material, dimension, thickness, density, rigidity, and damping of the panels to be used. This article was published in audioXpress, February 2008.

In this article Scott Dorsey tells us how to repair Switching Mode power supplies. As he explains, "there are a lot of books and articles out there about how to design a switching supply, but not many on fixing them. As switching supplies become ubiquitous in electronic devices today, it becomes that much more important to understand how they work and just as importantly how they fail." This article was originally published in audioXpress, January 2018.

Where do tubes come from? In this article Richard Honeycutt revisits the history of tube electronics, from its early invention to the widespread adoption in radios and television receivers. And because familiarity simplifies tube selection, the article explains where some of the most common tube types can be applied in todays designs on power amplifiers and pre-amplifiers and tube stages. This article was originally published in audioXpress, April 2013 as part of the Hollow-State Electronics monthly column by Richard Honeycutt.

In this article, Richard Honeycutt provides a brief description of the main tube types used in audio applications, from triodes to tetrodes and pentodes, describing its uses, features and potential benefits. If you are looking for a quick reference reading about tubes that have been used in audio amplification this article is a great start. This article was originally published in audioXpress, May 2013 as part of the Hollow-State Electronics monthly column by Richard Honeycutt.