Not long ago, we made up a late explanatory article on mqa encoding technology [doc]link=00007886[/doc], recalling that mqa is an abbreviation for master quality authenticated. Music files in mqa format are available in a pcm file size of about 1/16 cd specification, which can be authorized to finally achieve 24bit/352.8khz playback quality. Today, through matrix audio's flagship decoder, x-sabre pro, we can see how the mqa sound quality is under such a large scale compression.
Technical review and musical origami theory
First of all, I want to thank Matrix Audio for sending the x-sabre pro decoder that has just been done to us to experience MQA, they have just got the MQA official certification, and it is also after the last mqa release, we talked to Matrix audio about this matter, did not expect them to be very efficient, so quickly completed the final debugging. MQA certification needs to apply to the official, in the product firmware needs to have the relevant software design, and finally can pass the certification. X-sabre pro should not have forgotten, right? Before soomal wrote a review, it does have the strength of a million-dollar decoder, and the appearance of the workmanship is a must, you can review the dismantling and evaluation at that time. [doc]link=00007215[/doc][doc]link=00007232[/doc]
Before the experience begins, let's briefly review the characteristics of mqa and roughly explain what mqa is used to say about music origami. First, let's take a look at a picture of the bitrate of various common formats that we made at that time, of course, this seems to be not very intuitive, and then look at a 2l record label free download track file size. Isn't it clearer?
Bitrate comparison under different specifications of common audio formats - compare the size of mqa encoding
Norwegian 2l Records Free Audition Download - Visual comparison of file specification sizes
MQA files can play music in 24bit/352.8khz or 384khz on certified decoding hardware devices, but its file size is slightly 10% smaller than the 16bit/44.1khz files used for CDs. MQA is encapsulated using flac files, and its musical origami theory explains its low-to-high compatibility well. First, the mqa file can be a normal flac, which can be restored under any software that supports ordinary flac, if the software music player does not support mqa, then at this time it is a normal 24bit/44.1khz or 48khz file. This is the A-level unfolding in origami.
mqa Music Origami Theory - Level A Unfolding - No Licensed Hardware and Software
mqa Music Origami Theory-b-level unfolding mqa core - Unlicensed hardware with licensed playback software
MQA Musical Origami Theory - C-Level Unfolding - Full Decoded State
Second, mqa core, that is, the content of part b shown in the figure is decoded, at this time there is still no need for hardware part authentication, but a software player that supports mqa is required. For example, in the autorvana plus 3.0 version under macos, the mqa file will be decoded as a 24-bit 88.2khz or 96khz file for playback, of course, the hardware DAC part is also required to support this specification.
Third, full decoder, that is, the abc in the figure is fully expanded. At this time, the second type of player support is required, and external hardware devices are also required to pass the certification of MQA, and the devices that currently support MQA have Anqiao's dp-x1 player, Sony Zx300, a45 player, ifi's idsd bl sound card, of course, their sound quality is definitely far worse than today's moment sound x-sabre pro.
Finally, mqa also has a renderer, renderer and the above three-step decoding opposite, should also be considered encoder, but after all mqa is not a strict sense of the encoding, so called renderer, the official English instructions are more vague, probably means that the digital channel for old equipment can not support the transmission of more than 96khz, the higher specifications of the original file rendered for mqa, so that it is convenient for the back-end mqa at all levels of decoding.
We think that mqa's official set of music origami theory explains its compatibility graphically and conceptually well, and the software and hardware adaptation and licensing that need to be done in three stages. However, there is no logical correspondence between this origami and the display picture of a, b, and c information and the principle of real implementation, and how to achieve lossy compression mqa will not be discussed, which is the core technology to achieve file size. The logic that really achieves good sound quality is not to play out information above 20khz, 40khz or even 80khz, what is important is that it retains the sample rate when the dxd studio mastering state is unchanged. It is especially important for delta-sigma type adc and dac, which can be referred to our previous article.
Subjective hearing: mqa vs. lossless dxd and dsd, etc
<b>Test environment preparation</b>
Let's move on to the Subjective Experience section. At present, we want to experience mqa, of course, need to talk about several hardware devices above, of course, only ifi idsd bl and x-sabre pro is usb dac, the above Sony and Anqiao player although support usb mode, but in the usb dac mode is not supported mqa, only in the player mode support mqa. If you want to experience the mqa effect brought by the external decoder, the windows playback software does not know, macos can use the latest version of audirvana plus, this software seems to be priced at $49.
Matrix audio x-sabre pro external decoder
Apple MacBook Pro 13 [2016 Edition] laptop
Music program content, MQA is actually quite small, almost only Norway's 2l company strongly supported. There is some MQA content on Tidal streaming, and Sony Hi-Res also has MQA content purchased in China's sales channels, but it is almost all 2L company works. 2l.no official website also provides a number of free downloads of full-format auditions, including mqa, including 384khz or 352.8khz without mqa, as well as dsd/64/128/256. 2l official website download speed is touching, sometimes only less than 20kb per second, the best way is to use Baidu network disk offline download, because these free content as early as the network disk has a cache, so it can be completed in seconds.
The full decoded status of mqa under audirvana - the right side indicates the file specifications, and the left side indicates the running state
Decoding status of mqa core under audirvana - the right side indicates the file specifications, and the left side indicates the running state
As shown here, we bought a few mqa songs at Sony's hi-res music store and downloaded a few sets of free comparison music on 2l. For comparison formats, we will choose 16bit/44.1khz, 24bit/352.8khz [no mqa], dsd various specifications, 24bit/96khz and mqa for comparison. From the perspective of identifying whether mqa can challenge dsd or lossless 352.8khz dxd, we use the headphone set of stax sr009 and our high-end atmospheric earth cannon with the new Dirk a600 amplifier as a reference to avoid the impact of airpulse a100 digital amplifier a/d, of course, we also use a100 to listen. From the perspective of identifying whether mqa is too good for ordinary devices to hear the difference, we directly use the headphone output of the Macbook Pro and the external small earbuds to audition. We can play flac directly with the macos system, which is the lowest sample rate. We can also play it with audirvana, which is the second level of unfolded mqa, since the Macbook Pro does not support an 88.2khz sample rate, the software will play at 96khz. In addition, this situation also occurs on airpulse a300, a100. Let's move on to the subjective experience.
The mqa audition is screenshotted on the audirvana phone remote control
Audition song screenshot on audirvana phone remote control - note - 352.8khz original dxd specifications, non-mqa
You should know that 2l has produced a Blu-ray HD music record of "the nordic sound", which uses blu-ray as a storage carrier, and the built-in music is 24bit/96khz flac, which is a collection of 2l's earlier albums, bringing together the selected tracks in more than 2l records of the year, note, it is a collection. We chose Mozart's sonata for 2 pianos in dmajor, an excerpt from a double piano record in mozrt/grieg vol.ii: dena piano duo. Why do we say it so clearly? Because we specifically purchased the mqa version of this album. Since we want to compare, we need to ensure that the provenance is consistent. Neither this track nor this album is free. In addition, the 15th song in the collection, Haydn's string quartet "String Quartet in D Major No.5", was also used, fortunately this song is a 2l free audition, and can be downloaded to various specifications of dsd as well as dxd and mqa versions.
Audition song screenshot on audirvana phone remote control - note - cd specifications
Also free is arnesen: magnificat 4. et misericordia (cd-resolution), frank bridge variations: 4. romance, and we purchased the quiet winter night - an acoustic jazz project. 2l of sound recordings, especially the specifications are very complete, the highest specifications of dxd recordings, there is almost no large compilation of very dynamic works. So we see that most of the audition classical music is dominated by string quartets, piano violin sonatas, etc., while the rest are some new jazz, light music, local folk music, and very powerful choral recordings in the Nordic style of Norway.
<b>MQA full decoding compares dxd and dsd</b>
First of all, we have to verify whether the mqa technology is as good as it says, taking the 24bit/352.8khz flac corresponding to mqa as an example, its file size is 7-8 times that of mqa! This is in contrast to flac, which has been compressed by more than 50%. Compared with the original dxd pcm file, the size of mqa is only about 1/16 of the original, and its sound quality can not be up to standard?
From the subjective sense of hearing, some are more strange, and each piece of music is actually not necessarily the same. For example, the Mozart double pianos that appear in the featured collection are quite different from the mqa version. After comparing several other auditions, we wonder if 2l has done it again later? Or is the mqa full decoding state really much better for pianos, medium frequency thick, dynamic music, and 24bit/96khz flac? Indeed it is. Under this music, the performance dynamics of MQA are significantly better, the sound is solid and stable, and it is obviously more powerful. Sound distinctions are easy to distinguish.
However, several other songs such as string quartet, jazz light music "Quiet Winter Night", and bel canto female vocals are certainly not as obvious as the piano.
<b>Compared to CD sound quality:</b> We know that the recording quality of 2l and post-processing are quite high-quality, so even if you hear the most common 16-bit/44.1khz 2-liter audition, it is much higher than the level of popular music and even some audiophile discs you usually hear. While mqa is in the fully decoded state, it is easier to achieve better sound quality than cd specifications, and the main identification method is to listen to the transparency of the sound and the cleanliness of the level. But for some people who can't hear flac better than advanced mp3s, I speculate that the ability to appreciate mqa or even dsd is estimated to be worse. Therefore, there is no guarantee that 100% of people will appreciate it. But overall, we think this difference is easy to identify.
<b>Compared to lossless dxd sound quality:</b> mqa is a lossy 352.8khz, and dxd is the original lossless 352.8khz, this contrast is the time to really verify the color of mqa. Happily, after a very careful comparison, we think that this difference is negligible, to what extent? It should be much smaller than changing the AC input line. Of course, if there is a dsd as a reference, you will find that mqa and raw lossless dxd will be weaker when the dynamics of medium and high frequencies are relatively large. For example, the dynamics of the Violin of the Haydn String Quartet are not strong enough. However, for the bel canto female voice to sing softly, the difference in performance such as a clean and light violin is really very small. And in the low-frequency part, no difference was heard.
<b>Compared to the sound quality of dsd:</b> what do we mean when we say to use dsd references? If we think that the state of this music dsd is the best, it should have such a level of large dynamics and sound density, then lossless dxd is better than mqa. Because dsd is under x-sabre pro, no matter what type of setting the digital filter does, its sound is better dynamic than under pcm, high frequency density is better, resolution is better, and the sound is relatively hard. This is a big difference, how big is it? It's so big that it's extremely easy to distinguish. But from the perspective of enjoying music, we think that the performance of x-sabre pro under dsd is not necessarily better than that of dxd or mqa under pcm, and the sound under dsd is still slightly harder. But what about the difference between dsd and mqa caused by this hardware system? Or should dsd itself be so different from pcm and mqa? It is really difficult to judge, and it is impossible to verify the ideal state.
<b>MQA non-authorized low-end environment compared</b> to the above part We use the best possible hardware, as well as hardware that supports mqa full decoding to verify that the sound quality of mqa is not good enough. And now in this part, we are using the lowest configuration to verify how much mqa can be restricted in the case of not very good hardware, or even in the case of software and hardware that does not support mqa.
<b>No mqa feature comparison:</b> that is, the mqa file is played in the system using software that does not support mqa, but at this time it is also a 24-bit sampling accuracy flac, although the sampling rate is 44.1khz or 48khz. In contrast to it is the original cd specification, which is a 16bit/44.1khz file. It can be clearly heard that the level of mqa is still better.
<b>Expand the core level mqa:</b> with the audirvana player, with a decoder that supports 88.2khz or 96khz, and a sound card, you can achieve mqa core level decoding, and this hardware does not need to pass the official certification of mqa. From the actual listening point of view, if you only use the macbook pro built-in sound card playback, you can also reach 96khz, the sense of hearing compared to no support system playback, the improvement is more limited, especially with the notebook sound card direct output, the difference is even smaller. However, you can listen to other decoders such as Music State Mono 09, and you can still feel that the sound level and transparency have been strengthened. However, it is estimated that it is difficult to distinguish this difference between fungus, which is generally not interested.
Of course, there is no mqa full decoding in the introductory link today. However, in the sony a45 player review in a few days, we tried to find a way to make a comparison [a45 mqa playback does not seem to have any screen indication, so the review may not be successful].
<b>Summary of sound quality comparison:</b> Here is a summary of the sound quality aspects of mqa. First, mqa, with a file size of about 1/16, can almost achieve the sound quality of the original 24bit/352.8khz file, with only a very slight difference. Second, fully decoded mqa still has a relatively obvious advantage over 24bit/96khz in large dynamic performance. Third, mqa is about 10% smaller than the cd specification file can achieve significantly better sound quality than cd, even in the absence of decoding, core decoding of half mqa without additional certification can also be achieved. Therefore, mqa's performance in the full decoded state is truly outstanding, and even some exceed expectations.
<b>summary</b>
MQA was proposed by the British meridian audio in 2014, in fact, it was also proposed by their engineer Bob Stuart, it compares the unique file compression concept and the final effect is very useful for reducing the size of high-precision audio files, but we believe that this concept is related to the existing DAC/ADC working mode, and is not suitable for video or other fields. The compatibility of the three-level decoding actually provides better sound quality than the original non-compressed format in the case of non-certification, but compared with ape and flac, the mqa file is still twice as large as flac in the ordinary decoding mode. But as long as the software side supports mqa core decoding, its file size advantage and sound quality advantage are reflected. As for the hardware certification that can achieve full decoding, the sound quality performance and file size are technically quite amazing, but the popularity is still too weak.
The key points of mqa focus on two aspects: file size and authorization. MQA was originally designed to cater to the global streaming of digital music, the file size is smaller for Internet dissemination and portable device playback, and if it is mqa certified, the sound quality level is indeed very high. But so far, in addition to the sony Andy bridge players in total, there are lg v30+ and the essential phone support of the father of Android, which has been yellow, with minimal influence and quite unfavorable promotion.
The issue of authorization is even more troublesome. If this is a set of free technology, dare not say that it is with the streaming music market, but quickly kill ape among enthusiasts, flac becomes the most popular format should be achievable soon. However, due to the need for authorization from the music content itself, mqa's music content is very small, and the music that supports mqa in the vast music market is almost equivalent to zero. Even if it is the second level of core decoding, the software player licensing promotion is not favorable, and the market share is close to zero. As for the ultimate full decoding, there can be a flagship like x-sabre pro to join, to help show that mqa does have strength, at this stage than what mobile phone support is more effective. But in the future, MQA will definitely target the streaming music market.
From a technical point of view, MQA has done well enough, and from the perspective of application and content, it is still limited by the authorization system, making it difficult to have a breakthrough opportunity for technical advantages. According to the popular saying, MQA technology has no problem, what is more needed is to change its own pattern?