Jim Austin

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MQA: Aliasing, B-Splines, Centers of Gravity

Jim Austin | May 17, 2018 | 141 comments

The right thing at the wrong time is the wrong thing.—Joshua Harris

The sampling theory formulated by Claude Shannon in the late 1940s had a key requirement: The signal to be sampled must be band-limited—that is, it must have an absolute upper-frequency limit. With that single constraint, Shannon's work yields a remarkable result: If you sample at twice that rate—two samples per period for the highest frequency the signal contains—you can reproduce that signal perfectly. Perfectly. That result set the foundation for digital audio, right up to the present. Cue the music.

MQA, DRM, and Other Four-Letter Words

Features, Reference

Jim Austin | Apr 19, 2018 | 47 comments

In an article published in the March 2018 Stereophile, I wrote that critics have been attacking MQA, the audio codec developed by J. Robert Stuart and Peter Craven, by accusing it of being lossy. The critics are right: MQA is, in fact, a lossy codec—that is, not all of the data in the original recording are recovered when played back via MQA—though in a clever and innocuous way. For MQA's critics, though, that's not the point: They use lossy mainly for its negative emotional associations: When audiophiles hear lossy, they think MP3.

MQA Contextualized

Features, Reference

Jim Austin | Feb 13, 2018 | 173 comments

When you come to a fork in the road, take it.—Yogi Berra

Over one busy week in 1986, Karlheinz Brandenburg laid the foundation of a technology that a few years later would upend the record business. Brandenburg, a PhD student in electrical engineering at the Friedrich-Alexander University Erlangen-Nuremberg, was figuring out how to code digital music efficiently enough that it could be delivered over digital telephone lines. A patent examiner had concluded that what the application proposed was impossible, so over a week of late nights, Brandenburg produced the proof of concept and more. It was another decade before the technology—MPEG-2 level III, more commonly known as MP3—would find its true home, the Internet.

MQA Tested Part 2: Into the Fold

Features, Reference

Jim Austin | Jan 06, 2018 | 27 comments

Loss is nothing else but change, and change is Nature's delight.—Marcus Aurelius

Master Quality Authenticated (MQA), the audio codec from industry veterans Bob Stuart and Peter Craven, rests on two pillars: improved time-domain behavior, which is said to improve sound quality and what MQA Ltd. calls "audio origami," which yields reduced file size (for downloads) and data rate (for streaming). Last month I took a first peek at those time-domain issues, examining the impulse response of MQA's "upsampling renderer," the output side of this analog-to-analog system (footnote 1). This month I take a first look at the second pillar: MQA's approach to data-rate reduction. In particular, I'll consider critics' claims that MQA is a "lossy" codec.

Alta Audio Hestia Titanium loudspeaker

Floor Loudspeaker Reviews

Jim Austin | Jan 04, 2018 | 13 comments

Phrases like high fidelity and perfectionist audio suggest a central norm to which all things audio should aspire. Not a bad idea, in some ways, but if you look at the wide variety of loudspeakers out there that people love, from the old-school Auditorium 23s to the high-tech KEFs and Vivids, it can be hard to figure out what they all have in common.

Is High-Rez coming to Apple Music? Probably Not.

News

Jim Austin | Dec 29, 2017 | 53 comments

A recent post on Roon's forums drew my attention to an apparently new category at Apple Music, Apple's streaming service. The post pointed to an Apple Music page listing music curated by the ECM music label. After ECM "Playlists," "New and Noteworthy," and "Recent Releases" is a section labeled "High-Resolution Masters."

MQA Tested, Part 1

Features, Reference

Jim Austin | Dec 12, 2017 | 213 comments

I don't think I've ever seen an audio debate as nasty as the one over Master Quality Authenticated (MQA), the audio-encoding/decoding technology from industry veterans Bob Stuart, formerly of Meridian and now CEO of MQA Ltd., and Peter Craven. Stuart is the company's public face, and that face has been the target of many a mud pie thrown since the technology went public two years ago. Some of MQA's critics are courteous—a few are even well-informed—but the nastiness on-line is unprecedented, in my experience.

Pass Laboratories XA60.8 monoblock power amplifier

Solid State Power Amp Reviews

Jim Austin | Nov 22, 2017 | 29 comments

Years ago, when I was young and foolish (instead of old and foolish, as now), I was hanging out with a friend at a strip-mall strip club in a small southeastern city. A youngish lady approached our table in G-string and pasties and did a tableside dance. My friend's jaw scraped the floor; I, noting her lack of enthusiasm, was unmoved. The stripper noted my impassivity and stated, with irony that at the time I somehow missed, "You're a hard man."

John Atkinson, too, is a hard man, at least when it comes to audio gear. When, in January 2014, he reviewed the Pass Laboratories XA60.5 monoblock amplifier, he concluded, "It is the best-sounding amplifier I have ever used." High praise.

Benchmark DAC3 HGC D/A preamplifier-headphone amplifier

Digital Processor Reviews, Headphone Reviews

Jim Austin | Oct 26, 2017 | 83 comments

Much has been written about the divide in high-end audio between subjectivists, who trust their ears, and objectivists, who believe that anything not scientifically proven is fake news. I respect both sides and am skeptical of both extremes, and I like to think that's how most audiophiles feel. High-end audio is about experiencing music—that's the whole point—but scientific and technological rigor lie behind every real advance, past and future. I regret the cynical snake-oil salesmanship, bad thinking, and clumsy engineering that pervade certain parts of our hobby.

Devialet Diary

Features, Stand Loudspeaker Reviews

Jim Austin | Oct 19, 2017 | 12 comments

It's day five of our planned month-long stay à Paris, late April through most of May. My wife is here for work—for me, it's strictly for pleasure—and we're enjoying Paris's rich, sensual goodness: food, museums, architecture, coffee, people, food. And yet, earlier today, when we were out for a walk—we've been walking close to 10 miles each day, exploring the city—I realized that my life here has been missing something important.

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