MQA

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Jim Austin  |  Jun 06, 2021  |  First Published: Jul 01, 2021  |  128 comments
MQA has once again floated to the surface of the perfectionist-audio pond—not belly-up as some have hoped but forced there by relentless pursuit by anti-MQA predators posing as impartial jellyfish.
John Atkinson  |  Aug 14, 2018  |  47 comments
In a series of recent feature articles for Stereophile, Jim Austin has examined how the controversial MQA codec works: "MQA Tested, Part 1," "MQA Tested Part 2: Into the Fold," "MQA Contextualized," "MQA, DRM, and Other Four-Letter Words," and, most recently, "MQA: Aliasing, B-Splines, Centers of Gravity." I doubt there is a Stereophile reader who is unaware of the fracas associated with MQA, and I have been repeatedly criticized on web forums for describing its underlying concept as "elegant."

But elegant it is, I feel.

Jim Austin  |  May 17, 2018  |  160 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.

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.
John Atkinson  |  Mar 20, 2018  |  30 comments
Radka Toneff & Steve Dobrogosz: Fairytales: Original Master Edition (MQA)
Odin LP03 (original LP, 1982); Odin CD9561 (24-bit/48kHz MQA-encoded FLAC file; Tidal Masters stream; hybrid MQA-CD; original sample rate 192kHz; 2017). Arild Andersen, prod. (1982, 2017); Andreas Risanger Meland, exec. prod. (2017); Tore Skille, Tom Sætre, original engs.; Svein Vatshaug, Rune Sund Nordmark, recorder restoration; Thomas Baårdsen, Geir Iversen, digital transfer of original tapes; Morten Lindberg, Peter Craven, Bob Stuart, digital restoration; Erik Gard Amundsen, technical advisor. DAA (original LP); DDD (MQA). Except: "My Funny Valentine," ADA (LP), ADD (MQA). TT: 40:11
Performance ******
Sonics ******

"See her how she flies . . ." When I first heard that lyric, from Jim Webb's "The Moon Is a Harsh Mistress," sung by a hauntingly fragile woman's voice and supported by a sparse yet lyrical piano accompaniment, at an audio show in 1983, I got chills. Who was this empathetic singer? Back in my cabaret-musician days, more than four decades ago, I backed so many singers with beautiful-sounding pipes but who didn't seem to comprehend the meaning of the words—yet this unknown woman directly communicated the song's emotion.

Jon Iverson  |  Mar 13, 2018  |  271 comments
Enough has been said by now about the technical details of how Master Quality Authenticated (MQA) works to fill several books. But the technical details are only part of the story, and probably not the most interesting part—and they're certainly not what provokes the extreme emotional responses of many to the format. So let's jump into the business and practical aspects of MQA to which so many audiophiles are reacting.
Jim Austin  |  Feb 13, 2018  |  177 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.

John Atkinson  |  Jan 06, 2018  |  72 comments
An economy of information transmitted . . . what was encoded was only what was needed, nothing more. (footnote 1)

As I wrote in the January issue's "As We See It," Master Quality Authenticated (MQA), the encoding/decoding system developed by J. Robert (Bob) Stuart and Peter Craven, has been widely criticized, despite reports in this magazine and others that MQA-encoded files tend to sound better than the PCM originals from which they were derived. Also in last month's issue, Jim Austin investigated the time-domain performance of the MQA reconstruction filter and I examined some of the more general aspects, ending with: "Other criticisms of MQA involve its implications for the recording industry, for manufacturers of audio products, and for consumers. I will examine those in next month's 'As We See It.'"

Jim Austin  |  Jan 06, 2018  |  28 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.

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.
John Atkinson  |  Dec 11, 2017  |  139 comments
"The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point."—Claude Shannon

Since its announcement at the end of 2014, Master Quality Authenticated, the MQA encoding/decoding system, has spawned outspoken criticism. Some of the more thoughtful negative reactions have come from engineers such as Dan Lavry, Bruno Putzeys, and Daniel Weiss. Others have been expressed by manufacturers of digital products: the late Charley Hansen at Ayre Acoustics, for example, along with Jason Stoddard and Mike Moffat at Schiit Audio, John Siau at Benchmark Media Systems, and Jim Collinson at Linn Products. Some have been audio writers: Doug Schneider, at SoundStage!, and Paul Miller and Jim Lesurf, at Hi-Fi News. Most vociferous have been anonymous website posters. As Jim Austin remarks in his examination of MQA's decoding of impulse-response data elsewhere in this issue, "the nastiness online is unprecedented."

John Atkinson, Jason Victor Serinus  |  Jun 11, 2017  |  28 comments
MQA's Bob Stuart comparing PCM and MQA recordings in the Sunny Components room

Despite there now having been many opportunities for audiophiles to compare MQA-encoded recordings with the PCM originals—as well as comparisons at shows and dealer events, the Norwegian 2L record label has offered downloads of MQA/PCM files for quite a long time—there are still members of the press who insist that no-one, other than some reviewers, has been able to perform such comparisons. At the 2017 LAAS, not only were some exhibitors demonstrating MQA—Aurender, Meridian—Covina, CA retailer Sunny Components devoted the show's Saturday afternoon to specific comparisons hosted by MQA's Bob Stuart and Wilson Audio's Peter McGrath.

Jana Dagdagan  |  May 05, 2017  |  91 comments
With any large gathering of people who share a common passion, one is bound to encounter polarizing issues and the fiercely opinionated standing on either side. In the world, it's politics and religion. In our world, it's tubes vs solid-state, whether cables really matter or not, and, most recently . . . Master Quality Authenticated.
John Atkinson  |  Aug 18, 2016  |  67 comments
Last June, Jim Austin briefly discussed the operation of MQA in his review of the Meridian Explorer2 USB DAC, but you can find a more detailed explanation on Stereophile's website here and here. MQA involves two fundamental concepts, discussed in a paper presented to the Audio Engineering Society in October 2014. The first is responsible for a large reduction in the bandwidth required to store and stream high-resolution files, the second for a potential improvement in sound quality. . .
Jim Austin  |  Aug 16, 2016  |  33 comments
Most people who have heard music recordings encoded with Master Quality Authenticated agree that it sounds really goood (footnote 1)—but even they recognize that at least one major challenge remains: ensuring that listeners can actually get, in MQA format, the music they most love. I spoke with Spencer Chrislu, MQA's director of content services, about the company's efforts to meet this challenge.

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