audioXpress Magazine      July 2025

  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.

Mixed Senses And Audio Vocabulary
The law of diminishing returns.
Editorial By J. Martins
Writing about Music is like Dancing about Architecture, someone once said. I did use the sentence a few times, particularly in the years when I was the editor of a music publication and we had to convey in words how a performance or recording made us feel. At the time, I really had to master that art—after all, you want to do justice to artists and their music, and you need to keep readers engaged and wanting to buy the record. When I'm in a position to judge how things sound and I have to write about it, I am fully conscious that I am describing purely subjective impressions that are frequently ephemeral and subject to shift under different conditions, or at another time. Is Writing about Audio Like Painting about Philosophy? Yes, the process of picking words to describe emotions and general sensory perception is a bit like philosophy. It can be systematic, reflect critical thinking, and employ logical analysis, conceptual clarification, and argumentation. Robert Harley (of Absolute Sound fame) uses words such as tone color, and liquidity, to describe sounds, and I get it.
---> Mixed Senses And Audio Vocabulary.

5 Supporting Companies

Features
18 Illusonic IAP 8 Advanced Audio Processor And Preamplifier
By Philipp Paul Klose
The Illusonic IAP 8 is an advanced multichannel
audio processor and preamplifier with HDMI. It does
a whole lot more, but for this review, we focused on
the DSP and understanding the possibilities of the
work by Christof Faller and the deep expertise of his
supplier network based in Switzerland.

26 Burkhard Vogel Extends Valuable Knowledge On Op-Amps
By Jan Didden
Burkhard Vogel surprises with an extensively revised
second edition of his book Slopes and Levels, Spice
Models to Simulate Vintage Op-Amp Noise, with
10 additional new chapters on the noise-relevant
handling of input bias-current-compensated
operational amplifiers.

32 Beat Tracking Explained
By Estefanía Cano
For years, music technologists have designed
innumerable methods to automatically extract beats
from music tracks. The early attempts to create
automatic beat trackers in the 1980s have now
evolved into sophisticated AI-based algorithms we
find in many products today.

38 Linearizing Microphones CORE+ By DPA
By Eddy Bøgh Brixen and Toni Torras Rosell
CORE+ by DPA is a powerful technology at the heart
of DPA miniature microphones. It aims to provide
consistent, high-quality audio at all sound levels—
from a whisper to a scream.

46 A Microacoustics Modeling Primer Part 1
Analytical Implementation Methods
By René Christensen
This two-part article is a deep dive on the topic
of modeling acoustic losses in small or narrow
geometries, discussing various thermoviscous loss
models, and categorizing these models into analytical
and numerical approaches, highlighting the respective
implementation methods and computational
requirements.

54 Audio Amplifier Power Measurement
Using Arduino Technology
By David B. Soffer
This article details a practical project using Arduino
technology that provides instantaneous power output
readings, converting measured Volts to Watts with a
specific load resistance as the output of the amplifier
is changing.

Show Report
8 AXPONA 2025
The Best Show Yet
By Oliver A. Masciarotte
AXPONA 2025 was a great show. With 10,910 attendees,
more than 700 manufacturers, retailers, distributors,
brands from all over the world, thousands of products, and
more exhibition booths than ever. Oliver Masciarotte and
photographer Kurt Close flew through the more than 200
listening rooms on 12 floors to prepare this survey of
what’s new and notable.

Columns
Sound Control
27 Low Frequency, Very Low Frequency, And Infrasonic Annoyance
By Richard Honeycutt
This article highlights the problems and potential causes
of low frequency sounds and its potential effects over
some individuals, causing significant annoyance and discomfort.

Hollow-State Electronics
62 Instrument Amplifier Effects Loops
By Richard Honeycutt
Learn a bit about distortion and its evolution in amplifiers
over time. Also, discover why some effect devices are
better when used in front of the amp or in the effects loop.

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