All items in category Theory Articles
R&D Stories: Getting Started with Automotive Audio Bus (Part 1)
by Brewster LaMacchia

R&D Stories: Getting Started with Automotive Audio Bus (Part 1)

This is the first article in a four-part series about Analog Devices' A2B or Automotive Audio Bus, a digital audio bus technology originally developed for automotive requirements that is finding interesting design possibilities in other audio applications. This first article discusses the main features of A2B, and its use with I2S and PDM interfaces, before exploring the technical underpinnings of the A2B bus design and creating systems with the development tools available. This article was originally published in audioXpress, October 2020.
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CTA-2010: A Better Way to Measure Subwoofers
by Brent Butterworth

CTA-2010: A Better Way to Measure Subwoofers

Exploring the Standard Method of Measurement for Subwoofers (ANSI/CTA-2010-B R-2020), Brent Butterworth discusses how this might be a better method for avoiding the confusion on measuring bass extension of subwoofers. The article details how CTA-2010 measures usable output at 1/3-octave intervals within the subwoofer’s operational range, instead of measuring frequency response at a low sound pressure level. This article was originally published in Voice Coil, June 2021.
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Automotive Audio Solutions: Vehicle Electrification and Active Noise Cancellation
by Krunal Maniar

Automotive Audio Solutions: Vehicle Electrification and Active Noise Cancellation

As audio systems are expanding to integrate Active Noise Control (ANC), Advanced Driver-Assistance Systems (ADAS), and Acoustic Vehicle Alert Systems (AVAS) for quiet car sound design and autonomous driver alerts, Krunal Maniar (Silicon Labs) writes about Vehicle Electrification and Active Noise Cancellation, which are currently two key driving forces fostering innovation in In-Vehicle Infotainment (IVI) systems. The article also examines new challenges for OEM audio system designs and how they are being met.
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Practical Considerations for Quality Control Testing of Loudspeakers
by Dan Knighten

Practical Considerations for Quality Control Testing of Loudspeakers

Integrating a power amplifier, microphone power supply, and analyzer required for speaker tests, the article details how the Audio Precision APx517B can save time in the overall test process through reduced setup and configuration steps. The authors also explain how this new AP solution meets the need to balance the cost of test including time, test methods, and system cost, against "the cost of failure" that might result from the expense of warranty repairs, or the possible negative impact to brand from product returns. This article was originally published in Voice Coil, April 2021.
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How to Measure Free-Field Speaker Response Without an Anechoic Chamber
by Steve Temme

How to Measure Free-Field Speaker Response Without an Anechoic Chamber

One of the biggest challenges with working from home during the pandemic was not having access to an anechoic chamber. This short tutorial, explains a simple solution for this: a “splice” measurement. The capability for such measurements has been included in SoundCheck since 2001. Despite its long history, this method has not seen widespread use. However, the current pandemic’s working challenges are sparking renewed interest. This article was originally published in Voice Coil, March 2021.
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PEEK High-Performance Film Diaphragms and Cones for Headphones and Speakers
by Mike Klasco

PEEK High-Performance Film Diaphragms and Cones for Headphones and Speakers

This article takes a closer look at Polyetherether Ketone (PEEK) and comparisons with the PEI (polyetherimide) or polyethylene naphthalate (PEN) developments, and even standard PET formulas that dominate most cheap earphone and headphone diaphragm applications. The article also references key product implementation and the latest knowledge directly sourced from vendors and patent holders, such as DuPont, Teijin, and Victrex. This article was originally published in Voice Coil, May 2021.
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Comprehensive Transducer Testing in 24 Minutes
by Andrew Taylor

Comprehensive Transducer Testing in 24 Minutes

This article illustrates how the latest Klippel Multi-Scanning Workbench solution allows measurements across several domains (acoustical, mechanical, electrical, and magnetic) while working from non-anechoic environments. The author uses a practical characterization of balanced mode radiator (BMR) loudspeakers, which require a more complex approach when compared to conventional cone-based woofers or dome-tweeters. This article was originally published in Voice Coil, May 2021.
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Measurements Rate New SMT Low-Voltage JFETs Under Consistent Conditions - An Update Using Modern JFETs
by Dimitri Danyuk

Measurements Rate New SMT Low-Voltage JFETs Under Consistent Conditions - An Update Using Modern JFETs

In 2013, Dimitri Danyuk wrote an article that presented apples-to-apples test results for noise densities for several low-noise discrete, SMT, and n-JFETs. In this follow-up article, Danyuk brings us new measurements, updating his design note with measurements of JFET components that appeared more recently on the market. The tests used the same operating conditions so that designers can make a fair comparison for their applications. This article was originally published in audioXpress, December 2018.
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An All-JFET Amplifier: Exploring Modern JFETs Circuits
by Dimitri Danyuk

An All-JFET Amplifier: Exploring Modern JFETs Circuits

This article describes the design and performance of a high-quality DC-coupled all-JFET amplifier. The circuit was inspired by John Curl and Erno Borbely designs and was built with readily available junction-gate field-effect transistor (JFETs) from Linear Systems. The input stage is the the complementary JFET differential pair, the second stage is symmetrical differential amplifier with two pairs of opposite polarity JFETs, and the output stage is a complementary source follower. The amplifier can drive loads up to 150Ω. This article was originally published in audioXpress, October 2017.
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Contextual Awareness: What Is It, and How Is It Being Used?
by Elia Shenberger

Contextual Awareness: What Is It, and How Is It Being Used?

Context-aware devices, such as the embedded smartphone keyboards, have been around for some time, though in a very limited form. By learning regularly used names, locations and phrases, they seem to know your next move, that is, predictive text. Similarly, but at a higher level, the next generation of smart audio devices will combine user-specific data, such as location, preferences and other device sensor data, including audio, to better serve the user.
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