audioXpress Magazine      October 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
2 Editorial: More Room For Audio
And When I visited the first audio trade shows of 2022…
Editorial BY J. Martins

5 Supporting Companies

Features
18 Sumiko Phono Cartridges And RS78 78 rpm Stylus
By Gary Galo
Gary Galo reviews the Sumiko Olympia and the
Wellfleet phono cartridges, together with the new
RS78 stylus, Sumiko's first 78-rpm solution, designed
to meet the needs of many vintage recording
enthusiasts.

26 The Story Of aptX
An Epic Journey
By Jonny McClintock
From film sound to radio broadcasts, studios, and
finally to Bluetooth and more than 12 billion devices,
the successful story of aptX technology is inextricably
linked to the history of digital audio. Our author
details this remarkable corporate journey.

32 Replacing IEC 60268-5 (Part 2)
The Importance of Measurements
By Geoff Hill
Geoff Hill concludes his discussion about the work
taking place on loudspeaker measurement standards,
and the progress the International Electrotechnical
Commission (IEC) has made with its standards efforts.

42 Triode Common Cathode Stages, The Oracle Equation,
And Theodosian Objections
By Christopher Paul
For those readers interested in tube amplification, this
article proposes a simplified equation of what might
appear to be multiple mathematical factoids into a
single concept, intended to help characterize and
understand triode circuits.

48 Making a DC Power Supply With Audible Benefits (Part 1)
Choosing the Design
By Frans de Wit
Following two previous audioXpress articles that
explored multiple power supply circuits with potential
for high-end audio applications, Frans de Wit details a
high-quality power supply especially targeted toward
preamplifiers, record-players, and other low power
appliances.

54 All American Tower Speakers
By Ken Bird
In this article, our experienced speaker builder takes
us along with him on his quest to build a loudspeaker
made solely from drivers manufactured in the United
States.

Market Update — Residential Integration
Market Update
8 The Home Audio Perspective
By J. Martins
Since the adoption of automation systems and home
networks, residential integration has evolved gradually
to connected systems and is now increasingly associated
with the transition to the Smart Home. Learn more about
the audio companies that are facilitating the transition.

Sound Control
38 Considerations Concerning RT Measurement
By Richard Honeycutt
In this article, our acoustics expert explains the history
behind the reverberation time (RT) measurement and its
importance. He then shares his preferred procedure for
measuring RT.

Hollow-State Electronics
60 Old Timer, Williamson, and Ultralinear Amplifiers
Families of Hollow-State Power Amplifiers
By Richard Honeycutt
The July and September Hollow-State Electronics articles
examined the distortion performance of the three families
of amps. This article recaps those findings and compares
them to the last two families, the Williamson and
ultralinear amps.

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