Speaker Design: Driver-Induced Vibrations

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.

Acoustic reflections in rooms, in the form of reverberation, contribute significantly to the characteristic of sound. In acoustic measurements for quality testing of loudspeakers and microphones, however, these reflections can produce inaccurate results and should therefore be excluded as far as possible. The measurement results must be reproducible and not significantly influenced by the room acoustics. In this article, NTi Audio explains how to remove reverberation from the measurement results.

An article detailing the vast experience in this field by one of the leading designers and manufacturers of measurement microphones, PCB Piezotronics. The article looks at the frequency response of a measurement microphone, general acoustic calibration, and the benefits and challenges of free-field calibration, and pressure calibration, among other approaches. The article was originally published in Voice Coil, September 2017.

This article describes a spreadsheet program for designing low-voltage power supplies using common IC three-terminal regulators. The spreadsheets are in standard Excel format, and should work in just about any spreadsheet program. Each file has two main pages: one for use with common variable-output regulator chips, the other for fixed-output devices. This article was published in audioXpress, March 2010.

Do you know what the crossover filters are doing to the response of the loudspeaker system? Some of you might have measured the frequency response of the loudspeaker system to determine what’s happening through the crossover region. However, most designers only look at the loudspeaker’s on-axis response. It’s equally important, or perhaps more important, to know what’s happening off-axis. Let’s see how loudspeaker modeling can be used to help with this. This article was originally published in Voice Coil, August 2017.

In this article, Dan Knighten (Applications Engineer, Listen) provides valuable perspectives on how to deal with the challenges of measuring devices that connect directly to Apple’s Lightning port or USB-C, or work wirelessly, using Bluetooth. In all cases, these headphones present unique challenges to measurement because they cannot be directly connected to traditional test and measurement systems. This article was originally published in Voice Coil, July 2017.

Is the solid part of a loudspeaker motor just a magnet or is there more to it? Simulation tools have helped to create effective and powerful magnet constructions, which make it easy to build a prototype based on calculations and experience. The next obvious step is measuring and listening to the assembled speaker. However, more conclusions can be drawn by analyzing the individual parts further. This article was originally published in Voice Coil, May 2017.