All items in category Theory Articles
Measurement Microphones: The Good, Bad, and Ugly
by Mike Klasco

Measurement Microphones: The Good, Bad, and Ugly

Measurement microphones are a special class of microphones, ranging from laboratory precision instruments to products used for fine tuning sound systems in commercial or residential settings. Measurement microphone pricing varies greatly from $10 to 4,000. The quality differs immensely and there are many choices in between. This article was published originally in Voice Coil October 2012.
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Headphone Testing (Part 2): Digital Headphones (USB & Bluetooth) and Noise-Canceling Headphones
by Brian Fallon

Headphone Testing (Part 2): Digital Headphones (USB & Bluetooth) and Noise-Canceling Headphones

Headphones with built-in electronics, such as digital headphones (including Bluetooth and USB), and noise-canceling headphones are harder to test because the electronics and transducers need to be tested together as a complete system. This Part 2 article discusses those tests. Article originally published in Voice Coil April 2012.
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Headphone Testing (Part 1): The Basics
by Steve Temme

Headphone Testing (Part 1): The Basics

In this article, Steve Temme discusses the issues that are common to testing all types of headphones. As more and more loudspeaker engineers find themselves employed in the fast-growing headphone market, it is important that the unique challenges of testing headphone packages are fully understood.
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Phase Response and Receive Delay
by Charlie Hughes

Phase Response and Receive Delay

The question of phase response often arises when measuring loudspeaker systems. In this article, the author reviews setting the receive delay within a measurement system so that the displayed phase response is the “correct” one. This article was originally published in Voice Coil July 2011.
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Acoustic Resistance, Secret Sauce for Speakers
by Mike Klasco and Steve Tatarunis

Acoustic Resistance, Secret Sauce for Speakers

The application of acoustic resistance as a design element in the optimization of transducers and enclosures has been given short shrift in audio engineering. Controlling the acoustic resistance of the driver radiation is a quality factor that is overlooked in most loudspeaker predictive modeling software. This article explores applications of acoustic resistance for audio.
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Measurement and Perception of Irregular Loudspeaker Defects
by Wolfgang Klippel and Robert Werner

Measurement and Perception of Irregular Loudspeaker Defects

Loudspeaker defects caused by manufacturing, aging, overload, or climate impact generate a special kind of irregular distortion commonly known as rub & buzz, which is highly audible and intolerable for the human ear. This article, originally published in Voice Coil, June 2011, discusses how to measure and detect those defects.
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Measurement and Perception of Regular Loudspeaker Distortion
by Wolfgang Klippel and Robert Werner

Measurement and Perception of Regular Loudspeaker Distortion

This article discusses the physical causes of regular loudspeaker distortions, their modeling by using lumped and distributed parameters, the objective assessment using modern measurement techniques, and the perception by the human ear. Article originally published in Voice Coil, May 2011
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Audio Testing With Noise
by Ron Tipton

Audio Testing With Noise

Usually we think of noise as a signal to be eliminated, or at least reduced, in any audio system. However, noise can be a very useful test signal because it is inherently broadband, which is faster and perhaps more accurate than spot or swept frequency testing. Article originally published by Voice Coil, December 2010
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Power Transformers for Audio Equipment
by Pete Millett

Power Transformers for Audio Equipment

In this article, author Pete Millett explores the different types of power transformers, and why you might choose to use each type in audio equipment. The article addresses issues with low-frequency (50–60Hz) line transformers, but many of the same issues apply to audio-frequency transformers as well.
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Using All-Pass Filters
by Charlie Hughes

Using All-Pass Filters

All-pass filters are perhaps one of the most overlooked and misunderstood tools for the general audio practitioner. Much has been written about their use to yield more linear phase response through the majority of a loudspeaker’s passband. They can also be used to optimize the directivity and magnitude response of a loudspeaker system. Perhaps we should first look at exactly what an all-pass filter is.
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