Introduction to MQA
Publicly launched in 2015, Master Quality Authenticated (MQA) is the creation of Meridian (and now MQA Ltd.) company founder Bob Stuart and long-term collaborator Peter Craven. At its heart, MQA is a lossy compression audio codec intended primarily for the efficient streaming of high-resolution audio.
Much has been said about MQA, and like many aspects of audiophilia, it is a topic fraught with controversy. Much of the strife comes from the seemingly diametrically opposed concepts of the highest fidelity audio experience being delivered by a controlled, lossy format.
We’re so used to the idea of lossy mp3 sound being inferior to lossless formats such as FLAC that it is a struggle to understand how MQA can deliver what it promises.
Adding to the confusion is that MQA uses a unique set of terminology to describe its proprietary music conversion and retrieval process. Additionally, critics of the format are unhappy with the financial incentives and DRM baked into the format.
We’re going to look at both sides of the MQA discussion and investigate the promises and the concerns. Along the way, we will try to simplify the MQA process.
Let’s start with Bob.
Bob Stuart studied Psychoacoustics and Electronic Engineering at Birmingham University and Operations Research at Imperial College, London He co-founded Meridian in 1977 and stayed until 2014 when he founded MQA Ltd.
It is Bob’s background in Psychoacoustics that seems to play heavily into the creation of MQA. MQA claims that the format “opens a clearer window and delivers all the details and nuance of sound, to reach the heart of the music and the soul of the listener.”
These are, of course, subjective claims and challenging to quantify objectively.
MQA states that it uses only the minimal amount of digital data that is necessary, and to do this “we re-imagined digital sampling and playback using key insights from modern auditory science.” They claim that by combining sampling theory and insights gained from human neuroscience, MQA can more effectively convert music from analog to digital and back to analog.
The term ‘high-resolution’ audio is commonly associated with recordings that use higher-than-CD data rates and is typically focused on the size of the digital container that the music is packaged within.
However, resolution speaks to the perception of individual details in the music, which is more closely related to the time domain.
MQA takes the approach that the time-domain performance of anti-alias and reconstruction filters is paramount in music perception. They feel this aspect is the missing key to the design of high-fidelity audio encoding and equipment.
Here we run into the first of MQA’s unique lingo. MQA uses a ‘folding technique’ referred to as ‘Music Origami’ to encapsulate the audio into a smaller container designed to protect, preserve, and confirm distribution.
Furthermore, the container file includes all the original sound (claiming at least 15x more resolution than regular PCM). Yet, it is packaged in a smaller format (saving up to 80%), that can be more efficiently streamed and distributed.
MQA makes some big promises.
MQA’s Claimed Benefits
- MQA is a philosophy more than it is ‘just a codec.’
- It’s inclusive - anyone can play it. MQA will play back on any device to deliver higher than CD quality.
- When paired with an MQA decoder, the MQA file reveals the ‘original master recording.’
- The sound quality is optimized for the current playback device.
- It removes unintended and damaging audio artifacts.
- It gives assurance to the studio community that their work is heard as intended, and the listener knows they have received the approved original.
- It is an end-to-end system that delivers hitherto-unattainable highest quality sound and authenticates the result.
- MP3 files deliver just 10% of the original studio recording, while MQA reveals every detail of the original recording.
MQA encoding ‘folds’ a digital audio file to make it small enough to efficiently stream. The file is then ‘unfolded’ by the playback device for playback. The hardware determines what level of unfolding (and what associated audio quality is possible). MQA decoders automatically unfold as far as the device permits.
An MQA decoder is not required to play back MQA ‘standard’ sound quality. When the hardware is limited to single rate playback (44.1 or 48 kHz), the decoder prepares the signal to give the maximum sound quality from generic digital to analog converters. MQA calls this process ‘Origami B’.
MQA Core Decoder – Unfold 1 – Origami C
The Core Decoder unfolds the MQA file once to recover all the direct music-related information and deliver higher than CD-quality audio. It is included in some products with digital outputs, as well as streaming services such as TIDAL. Media players like Audirvana and Roon have also implemented the Core Decoder.
A laptop, tablet, or smartphone can perform MQA Core decoding in software, even if they are not natively capable of high-sample-rate playback or which have other audio restrictions.
The Core Decoder digital output is limited to 88.2kHz or 96kHz, and the sound quality is higher than from ‘No’ or ‘Authenticating’ decoders but lower than a ‘Full’ decoder.
MQA Render – Unfold 2 and 3
An MQA Renderer can connect to an MQA Core signal and take a bit-accurate signal from a Core Decoder to complete the final unfold and deliver a fully decoded MQA experience.
This type of device is available for mobile applications such as portable USB DACs and headphones. MQA Renderers provide analog output only through their managed D/A conversion.
MQA Full Decoder – Unfold 1, 2, and 3
The Full Decoder provides the highest possible sound quality decoding (all completed in one device), including precise file and platform-specific DAC compensation and management.
A full decoder can indicate MQA provenance and other information such as the original sample rate on its user interface.
I’ve seen MQA described as being “a solution in search of a problem.” MQA positions itself as the most desirable audio streaming format due to sounding ‘better’ than any other option. Inherent within this positioning is the proprietary technology that makes MQA work. But it’s not quite that cut and dried.
One aspect that makes critics uncomfortable is the financial incentives within the MQA business model. Companies such as Schiit Audio, PS Audio, and Linn Products have taken vocal stances against MQA due to the licensing requirements.
MQA collects a royalty payment per commercial MQA-capable playback device sold. Hardware manufacturers sell fewer devices if they do not have the MQA logo and certification.
Similar to a Digital Rights Management (DRM) process, an unpacked MQA signal cannot be digitally output from a device and can only be fed to an internal MQA-compatible DAC or output in analog form. This requirement limits consumer hardware choices. The more music is distributed in this format, the more the MQA company will (financially) benefit.
A smaller file format that is limited and controlled to playback properly only on ‘certified’ devices is beneficial for the companies supporting (and streaming) MQA, but is it advantageous to the end-user?
Only if it is audibly superior. But does MQA really sound better?
De-blurring the Music
Another bit of MQA terminology is the concept of de-blurring the music. They claim their focus on end-to-end delivery provides minimal time ‘blur’ and maximum ‘clarity’ of dynamic range (reducing errors such as modulation noise) in the music. They claim that the MQA combination lossless-lossy (FLAC) container can encapsulate every bit of the music.
MQA states that the traditional methods of evaluating high-resolution audio do not apply to them. Their lossy, lower-bitrate files simply sound better than traditionally encoded hi-res audio due to their time-domain-focused filtering techniques. It’s an applied neuroscience-focused approach.
Critics point out that the MQA minimum phase filter design introduces temporal distortion by creating phase anomalies, especially with higher frequencies. If the MQA filter is the default (or only) filter in a device playing standard PCM, it may well be sonically inferior to standard playback filters.
Artists such as Neil Young have publicly denounced MQA’s conversion of his music.
MQA promises to make music listening better. A lot of claims have been made regarding how MQA achieves these promises. Unfortunately, it isn’t all presented with absolute transparency but with a liberal sprinkling of technical jargon. Is it real or just marketing and empty promises?
MQA is a compromise for consumers, who stand to (perhaps) gain an audible improvement, but likely at the cost of freedom of choice and hardware purchase requirements.
MQA has many proponents and seemingly an equal number of detractors. Whether MQA is a worthwhile investment, or even if it sounds better than other current standards, is, unsurprisingly, something that you are going to have to decide for yourself.
Author Trav Wilson: Audiophile or Audio-Phool? I don’t claim to have golden ears with magical properties, nor any ability to create music. But I do have a deep appreciation for music, founded at a young age, and curated over the years. I’m also unapologetically a gear-head and love lights, buttons, meters, switches, and especially things made from traditional wood, leather, metal, and glass materials. As with everything, take it for what it is: this is just one person’s opinion. Runs noteworthy.audio.