Beyond High-Resolution

An Inside Look at Meridian’s Master Quality Authenticated (MQA)

Blog
Categories:
Digital-to-analog converters,
Music servers and computer audio,
Rock,
Jazz,
Classical
Beyond High-Resolution

Imagine a digital-audio encoding and decoding system that delivers far better sound quality than that of any previous analog or digital technology, including 192kHz/24-bit and quad-rate DSD. Now imagine that this system’s bit rate is between 0.8 and 1.5Mbps, down to one-tenth that of conventional “hi-res,” allowing it to be streamed or downloaded in standard FLAC or Apple Lossless file formats. Finally, consider the possibility that this system would be based on a single file format that is backward compatible with existing delivery systems and playback devices, from smartphone streaming to downloads that feed the highest of high-end home DACs.

Sound like an impossible dream? Read on, and I’ll show you how Meridian’s Master Quality Authenticated (MQA) pulls off this remarkable feat.

MQA in Practice
Before getting into the technical aspects of MQA, let’s review the basics. Master Quality Authenticated is an innovative and sophisticated new method of encoding digital audio that simultaneously improves fidelity and lowers the bit rate. It’s a suite of technologies that addresses the limitations of conventional digital audio by rethinking the entire chain, from acoustic source to playback device. It was developed by Meridian Audio co-founder Bob Stuart and longtime collaborator Peter Craven of Algol Applications.

In practice, MQA is delivered to listeners as a conventional lossless file, such as FLAC or Apple Lossless at 44kHz or 48kHz at 24 bits. If you play the file though a DAC without an MQA decoder, you’ll hear better-than-CD sound quality. If you play the file through a DAC with MQA decoding, you’ll hear the sound in the studio’s original bit rate, which could be anything from 44.1kHz to 384kHz (or higher), provided that your DAC can handle the studio’s sample frequency. This single-file hierarchical aspect of MQA has important implications for the technology’s adoption by record companies and content distributors.

The decoder can be implemented in many ways—partly integrated into a DAC chip, or as a bit of software in a phone, for examples. Every decoder will indicate to the listener when an MQA file is playing. Here’s where the “Authenticated” part of Master Quality Authenticated comes in; the MQA light or icon assures that what the listener is hearing on playback is exactly what the engineers heard in the studio. How does this happen? MQA ties the studio’s analog-to-digital converter and the listener’s digital-to-analog converter into what is effectively a single system. In addition, MQA’s rich metadata carries information about the particular analog-to-digital converter and encapsulation used to make the recording or transfer so that the decoder can play it back correctly. And if the decoder knows what DAC it’s driving, it can also optimize its sound. This is why MQA can claim to authenticate the studio experience for the listener.

As of this writing, more than fifty companies—from major players to niche high-end firms—plan to support MQA with compatible playback devices. Meridian has already launched its first MQA-capable DAC, the $299 Explorer2. The lossless streaming service Tidal is behind MQA in a big way; it will begin streaming MQA files in Q2 of this year. MQA allows Tidal to give its customers real high-resolution streams in a format that fits Tidal’s existing distribution infrastructure. In an e-mail exchange, Pål Bråtelund, Strategic Partnership Manager at Tidal, said: “At first, I thought the last thing the industry needed was another codec. But then Bob [Stuart] played some recordings I knew extremely well, and I instantly understood that MQA may be what makes people talk about great recordings and great music rather than about ‘hi-res.’”

For Tidal, and also for the world’s record companies, MQA solves the big problem of multiple inventories for different playback applications. A single MQA file works for every listener on every device. This backward compatibility and single inventory are powerful incentives for record companies and content distributors to adopt MQA—quite apart from the improved sound.

So now let’s address that confounding issue of just why MQA sounds better than any other format extant, and how it can do so at such low bit rates.