audioXpress Magazine February 2025

Home \| High-End Audio Reviews \| Audiophile Show Reports \| Partner Mags \| Hi-Fi / Music News
	High-Performance Audio Reviews Music News, Show Reports, And More! Celebrating 30 Years Of Service To Music Lovers

audioXpress Magazine February 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.

From the Editor's Desk: Love It Or Hate It, 2025 Is About AI
Wireless mics are a critical market segment too.
Editorial By J. Martins
There was so much we had planned to talk about in this issue of audioXpress... But as always, there's only a certain number of pages. We will definitely be coming back to the topic of microphones this year, given that a lot is happening in "conventional" and wireless microphones. And likewise, we will need to cover so much of what is happening in artificial intelligence (AI) and microphone integration for audio processing. Just as we are sending this issue to the printers, pre-CES news in this field continues to flow. In this issue's Market Update, we have discussed developments in the cutting-edge MEMS microphone space that represents a massive amount of business when it comes to capturing sound sources for recording or transmission. But that doesn't mean that the established non-MEMS microphone manufacturers have been sitting still. In 2024, we have seen important new designs and a lot of innovations that challenge established models in use.
---> Love It Or Hate It, 2025 Is About AI.

5 Supporting Companies

Features
22 mh acoustics Eigenmike em64
Sixth-Order Ambisonics Microphone
And Software Suite
By Philipp Paul Klose
mh acoustics' em64 Eigenmike spherical microphone
array contains 64 professional-grade omnidirectional
microphones mounted on a rigid spherical baffle.
The em64 allows for tremendous degrees of freedom
in projects requiring recording soundfields in any
location. From acoustic measurements to 360°
recording and complex soundfield analysis, the
patented design enables multiple use cases explored
in this article.

36 Sony MDR-M1 Closed Monitor Professional Headphones
A New Studio Stalwart
By Brent Butterworth
Sony's MDR-7506 headphones have been a fixture
in recording and radio studios for decades. The new
MDR-M1 promises to improve on the beloved 7506 — at
two and a half times the price. Brent Butterworth
finds out how the new model compares to the classic,
and to a top competitor.

44 Getting Out Of The Ear
The Evolution Of ANC Technology In Hearables
By Alex Bonnet and Eric Benhaim
With the AirPods 4 ANC, Apple recently showed that
active noise cancellation (ANC) is also possible in
loose-fit true wireless earbuds. This article provides
the perspective from a technology provider working on
advancements in ANC technology for open form factors.

50 A New Op-Amp For Phono Preamps
Part 1 — The Design
By Brian Lowe
Brian Lowe designed his first phono preamp more
than 40 years ago. After many more designs
with varying performance, Brian realized that for
maximum performance several often conflicting
factors need to be optimized and fine-tuned. So he
decided to design a ground-up discrete preamp.

56 Modern Op-Amp Distortion Tests
Part 2 — A Few More BJT Types And JFET Devices
By Douglas Self
Douglas Self has been using a tried-and-true palette
of op-amps in his designs. But many new types
have appeared in the last decade, and Douglas
thought it was time to evaluate those for distortion
performance. Here in Part 2, the measurement of BJT
types is concluded, and then JFET types move to the
test bench.

Microphones
8 Market Update
MEMS Microphones In The Age Of AI
By J. Martins
For more than 20 years, MEMS microphones evolved
to become the largest volume technology, despite not
overcoming the technical limitations to compete with
established condenser, dynamic, and other microphone
technologies. That is about to change with new products,
technologies, and new systems designed for the age of
AI audio processing.

18 Unlocking The Future Of Wireless Audio
An In-Depth Look At WMAS
By Nick Wood
Learn more about the work Shure has done to develop
robust and reliable solutions in the new Wireless
Multichannel Audio Systems (WMAS) regulatory framework,
reflecting its dedication to providing professionals with
the creative tools they need.

Columns
Sound Control
30 Sabine, Models, And Measurements
By Richard Honeycutt
From Sabine's equation and efforts with reverberation
time (RT), to calculating impulse responses (IR) and
acoustical modeling software, this article explores how
calculations and predictions compare with computer
model simulations and actual measurements.

Hollow-State Electronics
62 The Legendary Dynaco ST-70 And ST-70 II Tube Power Amps
By Richard Honeycutt
In 1959, Dynaco enticed audiophiles with its now
legendary ST-70 amplifier, also sold as easy-to-assemble
Dynakits. The ST-70 revealed an immense staying power
that lasted until 2016 in its Series III form, already offered
by Radial Engineering