MQA

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.

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.

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.

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.

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.

"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."