Input-Output Impedance Matching – Or Not

In analog audio, you often must connect a source to a “receiver” unit. Pre-amp to power amp, phono preamp to an active crossover, the crossover to the power amp, that sort of stuff. Each of these units has an input impedance and an output impedance spec. I often get questions like: “My power amp has 20kΩ input impedance, my preamp has 100Ω output impedance, and maximum load is specified as 10kΩ. Will that work together or will I break something?”. Jan Didden explains all about Input-Output Impedance Matching.

Regulator Needed for Stable, Noise- and Ripple-Free DC Relationship. Does your nice circuit get what he needs from the power supply? Jan Didden explores when a regulator is a regulator. ...when it regulates, you’d think. Yet, in many online fora and discussions you see circuits that ‘do something’ but there’s absolutely no regulation taking place.

I tested the Bose Ultra Open Earbuds and I'm Keeping Them. They sound great and allow listening at safe levels while being aware of what other people say. These make a great case for Open Ears and that's the topic of this article where I have inserted my review of the Bose Ultra Open Earbuds and I provide examples of how the industry has been exploring alternative designs that avoid in-ear occlusion, from loose-fit earbud shapes to the recent air conduction craze.

What is like to explore audio technologies in the massive show that is Mobile World Congress. A report from MWC 2024 in Barcelona from an audio product development perspective. Audio for mobile platforms, wireless technologies, wearables and true wireless earbuds and hearables. And lot's of AI! MWC 2024 has nearly returned to pre-pandemic size levels, closing with 101,000 attendees from 205 countries.

The Consumer Electronics Show has become a showcase of products of the future, and this year’s content was stronger than ever. The automotive sector in the West Hall was filled beyond capacity, with Mobility spilling into the North Hall. Roger Shively reports on how hardware-dependent development is shifting to software. How Artificial Intelligence has found a practical role. How it all changes car audio systems.

Back in 2020, Barry Vogel, the director of the Audio & Loudspeaker Technologies International (ALTI) Association called me excitedly about Niron Magnetics and about a new magnet material developed from research at the University of Minnesota. Iron Nitride (FeN) was perhaps the biggest news in magnets in 40 years. Composed of common elements — Iron and Nitrogen - the potential of permanent magnets from Niron could be a breakthrough and a game-changer for the audio industry.

I returned from Barcelona, Spain, after five exhausting days, which were not easy for anyone in the audio industry who was forced to fly from the NAMM Show in Anaheim, CA directly to Europe. I wrote this First Impressions ISE 2024 report in an effort to summarize this extremely well organized and successful event - celebrating the show's 20th anniversary. I discuss what is sustaining this systems integration event that everyone understands as many different things, and what does it means for the audio industry.

CES2024 was the best in a long time. I said that in my First Impressions article, and as we distance ourselves from the whirlwind of those hectic six show days, the stronger that feeling grows. And one of the reasons has to do with the fact that important technologies are already making a difference in the audio products that we will soon see in the market - while many others are about to. And there are clearly companies that left us with very positive, lasting impressions that we can and need to share.

CES 2024 was the best in a long time. audioXpress attended to report about the solutions and technologies that will enable the audio products of tomorrow, exploring the many hospitality and business suites where the audio industry is at during CES. We focused on attending closed demonstrations - about which we can reveal very little at this stage - because that's the only way to truly share the product developers’ experience, and gain a real perspective about the audio technologies that matter for product development and those that will determine the products in 2025 and going forward.

Douglas Self shares real experiments when selecting electrolytic capacitors to achieve the lowest distortion. An experiment inspired by his recent audioXpress article, "Optimizing Variable-Frequency Tone Controls," available online. This short piece is an interesting closer examination on the subject for audio circuit designers. Originally published in The Audio Voice newsletter, #453, January 11, 2024.