Some Big Questions About MQA

Gordon Brockhouse


Published: 11/20/2016 09:02:39 AM EST in Sound

Some Big Questions About MQA

The MQA format, which promises to alleviate many of the undesirable effects of digital recording, and deliver high-resolution music in a CD-resolution footprint, was one of the biggest stories of CES 2016. As the clock ticks down toward CES 2017, there are still some big questions about the format, the most pressing being, "Where's the content?"

Developed by Meridian Audio and later spun off into a separate company, MQA has drawn support from a few small audiophile labels and download services. But in May, MQA announced a licensing deal with Warner Music Group. Then in mid-October at Rocky Mountain Audio Fest in Denver, CO, MQA announced that it was in the process of encoding the entire Warner catalog in MQA format.

Following RMAF, Spencer Chrislu, Director of Content Services for MQA Limited, said that MQA had already encoded "hundreds of titles, if not thousands" of Warner titles. He also confirmed that MQA is talking with the two other major labels (Sony Music Entertainment and Universal Music Group) as well as Merlin Network, a digital rights agency that represents independent labels.

"Hundreds, if not thousands" sounds impressive, but that's just a tiny part of the Warner catalog. The actual encoding process is automated, Chrislu explained. What takes time is having the finished product approved by the studio and artist, as well as the up-front work of confirming that the content provided by the label is truly high-res rather than upsampled Red Book. In other words, the real bottleneck is doing due diligence on provenance.

What about TIDAL, which is said to be planning to offer streamed MQA content? "We're doing the work needed to make it a compelling offering when it goes live," Chrislu told me. But he wouldn't say when this might happen, or whether TIDAL would have a separate tier for MQA.

THE PLAYBACK CHAIN

When we spoke at CES 2016, Chrislu was insistent that users will need an MQA-enabled DAC to decode MQA content played from a PC or Mac, although they can play MQA content at CD resolution on a conventional DAC. At least that was my clear understanding until I connected a Bluesound Vault 2 to my system.

vault

Lenbrook's Bluesound brand is an MQA licensee, and I fully expected the Vault 2 to output MQA content through its analog output. This it did, with very satisfying results. Just out of curiosity, I decided to see what would happen when I played MQA files through Vault 2's optical digital output to the built-in (non-MQA) DAC on my amplifier. I expected that the Vault 2 would send a non-decoded 44.1 or 48kHz stream to the DAC. Much to my surprise, it sent high-res audio, 96kHz in the case of a Rickie Lee Jones track ("Last Chance Texaco"), 88.2kHz with a Dave Brubeck track ("Take Five"). The Vault 2 was apparently decoding the MQA files in software, then sending high-res to the DAC.

The results were illuminating. I compared sound of these two MQA tracks playing through the analog and optical inputs of my Neo 340i amplifier; and they were almost identical. The benefits of MQA processing were clearly present in both the analog and digital outputs from the Vault 2.

rickThe MQA versions were a marked improvement over standard CD-resolution files. Compared to a CD-resolution stream from TIDAL, the MQA file of "Take Five" was smoother, with more tactile and impactful bass and drums, and less digital glare. Compared to a CD rip in ALAC format, the MQA file of "Last Chance Texaco" was also smoother and less jangly, with less digital edge around the voice and guitar. Of course, some of these differences might also be due to differences in the provenance of the files.

This experience surprised me, as I thought MQA decoding without an MQA-certified DAC was either not allowed or not possible. In fact, it is allowed, says Greg Stidsen, Director of Technology and Product Planning for Lenbrook International, at least for content providers. "There are two ‘curated' streams by the studio," Stidsen responded to my query, "the encoded 16/44.1 stream, and the decoded 24/96 stream. DACs with higher than 96kHz sampling can perform further post processing to optimize for the local DAC. It is my opinion that most of the modern high sampling rate DACs have highly optimized reconstruction filtering and don't benefit as much from the MQA post processing. But they need to be fed a high sampling rate signal (like 88.2 or 96). The bigger gains come from compensating for the ADC in the MQA decoder."

According to the official MQA position, which Stidsen passed onto me via e-mail, "When MQA is previewed and approved in the studio, a ‘digital out decoder' is one of [the] preview options. This preview process ensures all applications of MQA playback are fully approved and authenticated. ... This MQA Decoder ‘knows' its playback environment and unfolds the stream to the ability of the playback device. When decoding for a digital output, the stream is optimized for a generic 96kHz-capable DAC."

All this raises some very interesting questions. Essentially, the Vault 2 is a dedicated music computer. If it can decode MQA content in software and output high-res audio via the digital output to a non-MQA DAC, can the same be done on a PC or Mac with MQA-enabled playback software? If studios can play decoded MQA files through a standard (non-MQA) high-resolution DAC, why can't consumers?

I asked Chrislu about that during our interview and followed up by e-mail with MQA's PR agency. A month later, I still haven't heard back. But right now, it appears that if a special MQA-capable DAC is required to play MQA content from a PC or Mac in high resolution, the reasons will have more to do with MQA's business model than the underlying technology.





Article Tags:  MQA, Lenbrook, Bluesound, DAC, Chrislu, Stidsen, content, studio, label, Warner, Universal, Sony, Merlin

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Some Big Questions About MQA








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