audioXpress Magazine      November 2022

  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
4 Wireless And DSP Evolution
What will trigger that evolution, we still don't know.
Editorial BY J. Martins

5 Supporting Companies

Features
8 Parts Express 2022 Speaker Design Competition
By Thomas Perazella
After a two-year hiatus, Parts Express sponsored its
annual Speaker Design Competition, and our author
was invited back as one of the three judges. Here, he
describes some of the amazing speakers presented at
this year's design competition.

28 Lundahl Transformers
How High Performance Transformers Are Made
By Scott Dorsey
Scott Dorsey recently fulfilled his dream of visiting
the Lundahl Transformers factory, located in the small
town of Norrtälje, just outside Stockholm, Sweden.
In this article, he shares what he learned about the
manufacturing of these transformers.

40 Solutions for Building Voice User
Interfaces at the Network Edge
By Matthew Mitschang
Voice interfaces require AI and machine learning
processors directly on-device. Learn more about how
the level of computation for voice processing using
edge-AI optimized processors also enables exciting
possibilities for highly sophisticated audio processing
in applications from low-power earbuds to automotive
interfaces.

44 How to Choose The Right Signal Processing Technique
By Dave Betts
Noise is all around us making it difficult to pick out
and clearly hear one voice amid the cacophony.
Electronic devices have the same issue. However, signal
processing techniques can come to the rescue. Learn
which ones to use for which applications — and why.

50 Making a DC Power Supply With Audible Benefits
Part 2 — Real Improvements
By Frans de Wit
In this two-part article, Frans de Wit considered all
the factors and design options for a high-quality
power supply especially targeted toward low power
appliances. In this continuation, he performs
simulations that demonstrate real improvements.

58 Power Transformer Parameters, Selection, And Testing
Part 1 — Transformer Core Materials
By Chuck Hansen
Based on his extensive experience in the design and
specification of current transformers, Chuck Hansen
has a lot to share about power transformers. The
first part of his new article series explores ideal
transformers, magnetic core materials, variations in
properties, and cost factors for magnetic materials.

Market Update — Residential Integration
18 Improving Wireless Audio Part 1 — The Growing Pains
By J. Martins
Wireless audio evolution can still take place and is in
no way constrained by the recognized limitations of current
Bluetooth technology — Classic and LE Audio. This market
update discusses the efforts and the most promising
platforms and technologies for wireless audio.

Columns
Sound Control
34 Updated Smartphone SPL Apps
By Richard Honeycutt
Recently, a colleague asked Richard Honeycutt about
smartphone apps for measuring sound pressure level (SPL).
After conducting some research, he decided to provide
readers with an updated look at what is currently available.

Hollow-State Electronics
62 Voltage Regulator Tubes in Audio Amplifiers
By Richard Honeycutt
Our hollow-state electronics columnist details the history
of voltage regular tubes and discusses some of the merits
of their use in audio amplifiers.

Subscribe To audioXpress Magazine
Click here to subscribe to audioXpress magazine.

Previous Issues

2022
January   February   March   April   May   June   July

August   September  October

2021
January   February   March   April   May   June   July

August   September   October   November   December

2020
July   August   September   October   November   December