audioXpress Magazine      June 2024

  audioXpress remains the authority on audio and reproduced sound by connecting manufacturers and distributors with developers, buyers and consultants around the globe! It's readers are the audio product designers, consultants, integrators, DIY enthusiasts, opinion leaders and your best customers. All of them agree that the coverage of trending topics, unique in the audio industry, make audioXpress a must read.

Every month, audioXpress combines the best educational articles on topic such audio electronics, speaker and headphone design, amplifiers (from tube to Class D), acoustics, practical test and measurement, audio engineering praxis, and standards. audioXpress provides inside stories on new audio developments, on R&D Stories, the most complete objective reviews of innovative products and software, and selects some of the best DIY audio projects from worldwide experts.

From the Editor's Desk
Different Listening Perspectives
Automotive audio today is designed for immersive experiences.
Editorial By J. Martins
I recently attended a very successful AXPONA (Audio Expo North America) 2024 edition in Chicago, IL, where I was pleasantly surprised with the vibrant showcase of audio systems that filled the largest number of rooms in the history of this show. Hundreds of rooms with lots of innovative speakers to discover (some doing their premiere here, instead of waiting for the High End show in Munich), but also lots of new electronics, including many network audio streamers, which were clearly the most popular audio source, followed in a distant second by vinyl and CD — which are both mandatory as many attendees bring their own physical media to listen to for reference. These high-end streamers are now a core hifi component because they allow an aggregation of streaming services, enabling sessions to freely pick tracks from the Tidal, Qobuz, or Apple Music, all of which now offer lossless streaming options — or local NAS and storage devices for Hi-Res PCM and DSD files.
---> Different Listening Perspectives.

5 Supporting Companies

66 Article Update

Features
36 Using Multiphysics Simulation For An
Electrovibroacoustic Analysis Of A Balanced
Armature Transducer
By Jinlan Huang
This article explains how multiphysics modeling and
simulation can be used to analyze electroacoustic
transducers. Using a balanced armature (BA)
transducer as an example, the analysis combines the
electromagnetic field with structural vibrations and
acoustic radiation using multiphysics couplings.

46 Dimensional Reduction For Vibroacoustical Simulations
By René Christensen
Computational demands can be very high when doing
simulations involving coupled physics, as is often
the case for vibroacoustical transducers. This article
looks at how to reduce the computational demands
and associated costs utilizing symmetry schemes and
dimensional reduction techniques, and the potential
associated issues.

52 Measuring MEMS Microspeakers
By Steve Temme and Michael Ricci
MEMS microspeakers 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.

56 A Low-Feedback Triode Amplifier With Zero Output Impedance
Part 2 — Balanced Input Amplifier Design,
Performance, And Detailed Calculations
By Tim Mellow and Peter Farrow
The first part of this article introduced the Zero
Output Impedance amplifier concept and discussed
the design for a single-ended input version. In this
second part, the design is extended to a balanced
input configuration. Also, performance measurement
figures are discussed, and two Appendices give design
calculations for both configurations.

Columns
Hollow-State Electronics
62 Classic Hollow-State Hi-Fi Before 1950
By Richard Honeycutt
The term high fidelity (later shortened to "hi-fidelity" and 
eventually just "hi-fi") was used as a marketing label in the
1950s to promote the difference in sound reproduction from 
the technologies available in previous decades. Yet, 
high-fidelity was not exactly a new concept in
home music playback systems.

Automotive Audio
8 Moving Audio Into An Era of AI And SDV
By Roger Shively
Automotive audio is shifting from hardware-dependent
development as the industry embraces software-defined
vehicles (SDVs) and Artificial Intelligence (AI) finds a practical
role. How is this changing audio systems in the car, and what
changes in the way audio systems and infotainment are designed?

18 Integrated Audio Development Frameworks
By Philipp Paul Klose
Developers and designers are familiar with a number of 
audio frameworks that enable more time for actual innovation
and less time to write code, debug, and test hardware deployment.
New and existing integrated development environments (IDE)
are essential as automotive audio evolves in tandem
with software-defined vehicles.

26 Harmonizing The Future
Crafting Immersive Driving Experiences For Electric Vehicles
By Jasper de Kruiff, David Speith, and Lukas Joas
Vehicle sound design is essential to ensure that the transition 
from combustion engines to electric power doesn't compromise 
the thrilling essence of driving. For this purpose, Impulse
Audio Lab created EVx, a specialized software suite for 
the creation of dynamic and complex sounds.
Haptic seats developed by Icon Incar add synchronized
tactile feedback and create a compelling synergy of audio and haptics.

32 Car Audio Tuning And Upgrading
The Crucial Question
By Ken Ward
Aftermarket car audio always needs to be built on top of
the audio systems that the manufacturers designed.
This provides an opportunity to understand what works and what
can be improved. A perspective that is always valuable for any designer.

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