All items in category Magazine Articles
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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Patent Review: Multi-Layer Voice Coil Plate and Flat-Type Speaker Comprising the Same
by James Croft

Patent Review: Multi-Layer Voice Coil Plate and Flat-Type Speaker Comprising the Same

In this patent review, James Croft (Croft Acoustical) looks closely at a new patent of a multilayer voice coil plate and a flat speaker including the same type of multilayer voice coil plate, granted to three inventors from South Korea, on behalf of ICUBES Co., Ltd., Gyeongi-do, Korea. Detailing multiple configurations of this interesting concept, this patent offers an interesting take on the quest for the realization of a high-performance, one way, full-range electrodynamic transducer.
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Patent Review: Acoustic Passive Radiator Rocking Mode Reducing
by James Croft

Patent Review: Acoustic Passive Radiator Rocking Mode Reducing

With the increasing popularity of miniaturized systems, the application of the passive diaphragm radiator, as the acoustic mass component in a bass reflex enclosure, is becoming standard practice in the low-frequency portion of the system. And these systems have a few parameter demands that can exceed the capability of many conventional approaches to passive radiator design. In order to solve those challenges, including rocking modes, Bose proposed an effective design.
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Patent Review: Acoustic Filter for Omnidirectional Loudspeaker
by James Croft

Patent Review: Acoustic Filter for Omnidirectional Loudspeaker

This is an interesting patent awarded to Lakshmikanth Tipparaju, Allan Devantier, William Decanio, and Andri Bezzola, on behalf of Samsung Electronics - effectively the audio research team that Samsung created in Valencia, CA. The industry has attempted to achieve a successful implementation of acoustic radiation closely coupled to a boundary surface for omnidirectional and subwoofer applications - unfortunately, mostly plagued by resonances generated by the waveguide or reflector surface. This new approach appears to be an effective solution.
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Room EQ Wizard (REW) - Looking Back on Audio Measurement Software History
by Philipp Paul Klose

Room EQ Wizard (REW) - Looking Back on Audio Measurement Software History

This article revisits 20 years of Room EQ Wizard (REW), one of the mainstays in the audio measurement tool landscape with a strong user base. What started out as a side project for John Mulcahy, the creator and only developer, evolved to become a very complete and useful suite for both enthusiasts and professionals - a comprehensive set of measurement software tools bundled in a free package. This entertaining history of REW is also a fit way to commemorate the software's 20th anniversary.
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Microphone Array Beamforming with Optical MEMS Microphones
by Michael Tuttle and Jakob Vennerød

Microphone Array Beamforming with Optical MEMS Microphones

This article, written by the experts in optical MEMS microphones from sensiBel expands on the technologies that will undoubtedly contribute to making the next generation of hearables and advanced audio systems. As the Norwegian company enters the market with its first-generation products, the authors explain how 80dB SNR optical MEMS microphones will enhance Microphone Array Beamforming and the different types of beamforming algorithms.
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