All items in category Magazine Articles
For the Love of Music: Loudness Normalization
by Thomas Lund

For the Love of Music: Loudness Normalization

Wild theories about level normalization "destroying sound" continue to reappear, as if decades of loudness normalization efforts have been for nothing. This article hopes to set the facts straight regarding loudness concepts, standards, and implementation. Loudness normalization not only tremendously improves the listening experience for consumers, but it is also an element in control of sound exposure and prevention of hearing loss.
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The Secret Life of Loudspeaker Flex Wire
by Mike Klasco

The Secret Life of Loudspeaker Flex Wire

This valuable tutorial on speaker lead-out flex wire by Mike Klasco revisits the fundamentals, from the trailing ends of the voice coil winding to speaker terminals. How to avoid flex wire whipping, fracturing of lead-out conductors, thermal issues, and corrosion of the solder joints. What types of flex wire and wire gauges are available, what are the advantages of textile fibers and wire testing, are some of the topics addressed. This article was originally published in Voice Coil, April 2024.
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R&D Stories: The Neurochrome Story
by Tom Christiansen

R&D Stories: The Neurochrome Story

A personal account of a professional journey that led to the creation of Neurochrome, a company successfully serving audio enthusiasts all over the world with a complete range of power amplifiers kits and circuits, all well-engineered, thoroughly tested, and well-documented. Neurochrome is a small, highly dedicated audio company, providing inspiration, or perhaps a forewarning, for those wishing to venture into the audio business.
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R&D Stories: Using Multiphysics Simulation for an Electrovibroacoustic Analysis of a Balanced Armature Transducer 
by Jinlan Huang

R&D Stories: Using Multiphysics Simulation for an Electrovibroacoustic Analysis of a Balanced Armature Transducer 

This article explains how multiphysics modeling and simulation can be used to analyze electroacoustic transducers. Using a balanced armature transducer as example, the analysis combines the electromagnetic field with structural vibrations and acoustic radiation using multiphysics coupling features. A moving mesh is also used to model the back Electromotive Force (EMF).
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SPL Graph Data: Let’s Get Back to a Level Playing Field
by Tom James

SPL Graph Data: Let’s Get Back to a Level Playing Field

This excellent thought piece by loudspeaker industry veteran Tom James, addresses the often disregarded topic of speaker measurements and the corresponding variables of SPL Graph Data. In his short essay James explores the impact of ignoring or intentionally manipulating the rules established in the "Scales and Sizes for Plotting Frequency Characteristics and Polar Diagrams," defined in the IEC-602632 standard, originally from 1982 and updated in 2020.
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Practical T&M: Measuring MEMS Microspeakers
by Steve Temme and Michael Ricci

Practical T&M: Measuring MEMS Microspeakers

MEMS microspeakers are a completely new class of product with its unique challenges. MEMS drivers are now commercially available and seeing fast evolution and adoption in true wireless stereo (TWS) earbuds and in-ear monitors (IEM). With the emergence of these small form-factor transducers comes the need to address how to measure its performance and ensure product quality, even before its integration in finished products.
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Simulation Techniques: Dimensional Reduction for Vibroacoustical Simulations
by René Christensen

Simulation Techniques: Dimensional Reduction for Vibroacoustical Simulations

As computational demands can be very high when doing simulations involving coupled physics - such as is often the case for vibroacoustical transducers - this article looks at how to reduce the computational demands and associated cost utilizing symmetry schemes and dimensional reductions techniques, and the potential associated issues. This article was originally published in audioXpress, June 2024.
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Patent Review: Head-Related Transfer Function Equalization and Transducer Aiming of Stereo Dimensional Array (SDA) Loudspeakers
by James Croft

Patent Review: Head-Related Transfer Function Equalization and Transducer Aiming of Stereo Dimensional Array (SDA) Loudspeakers

This patent, awarded to Polk Audio, describes a very specific loudspeaker design that claims to be able to achieve better stereo sound reproduction with “a realistic ambient field and a larger, and more stable acoustic image.” This obviously aims at achieving something that Polk Audio actually patented nearly 40 years ago, with its original Stereo Dimensional Array (SDA) loudspeaker, and for which the new updated patent now provides a new improved version. This article was originally published in Voice Coil, February 2019.
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Unveiling the Impact of Ear Canal Geometry for In-Ear Headphone Testing
by GRAS Sound & Vibration

Unveiling the Impact of Ear Canal Geometry for In-Ear Headphone Testing

Frequency response is not the only important factor in testing in-ear headphones, and instead, the listening experience is largely influenced by how the pressure field is built up in the semi- or fully closed ear simulator, making leak and insertion position overshadowing parameters. This article shares the simulation work to assess the pressure field and its impact on different ear canal geometries, with surprising conclusions, fundamental to ensure consistency and repeatability when characterizing in-ear devices.
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Improving the Transfer Function of Electrodynamic Loudspeakers
by Reinhold Lutz

Improving the Transfer Function of Electrodynamic Loudspeakers

This article compares motion feedback technologies applied to speakers. A recognized expert in this field, Reinhold Lutz explores how to achieve a nearly perfect electro-acoustic transfer function, including a detailed control strategy of different types of sensors. A great exploration of how a closed-loop feedback system is able to improve loudspeaker linearity.
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