Unfolding MQA: how to play MQA
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Does MQA work with Roon and my DAC? Will my Tidal app offer me full MQA quality? If Tidal sends me a 48 kHz file, does the
MQA decoding do upsampling? Just a number of questions I get asked a lot. Time for some answers. MQA uses new insights in how we hear music
to reduce the amount of data needed for high resolution audio. Weren’t we told the same by Dolby: Dolby
Digital – which uses lossy compression – should sound just as good as the original PCM signal. And it didn’t, which is easily proven by
the fact that we now have Dolby TrueHD. MP3 and AAC- also lossy compression schemes
– are not identical to the original either. Whether you hear the difference depends on
your equipment, your hearing capabilities and your listening environment. In a car at 130 kph you probably won’t hear
a difference. And then came MQA, again three characters
and again using lossy compression.
So the tech-purists condemned it, even without
listening to it. For when you listen to it over a full MQA
enabled system, you will know it often sounds even better than standard 24 bit 192 kHz PCM. Watch my video “Is MQA lossless” for more
information. Links at the usual places. Time for the questions. You can play MQA files on any device that
can also play normal PCM files like WAV, FLAC, AIF and so on. What you get then is a quality equal to or
better than a normal 44.1 or 48 kHz 16 bit file. The quality can be better since usually the
original master – or a production master closest to the original master – is used for the mastering
of MQA. And MQA uses a filtering that repairs time
smearing in the production equipment to some degree. Furthermore MQA promises to never offer upsampled
files; if a master is at 44.1 kHz, the MQA signal – even when using the full MQA decoding
– is also 44.1 kHz.
If the master is at a higher sampling frequency,
like 96 or 192 kHz, non-MQA equipment will see a 48 kHz file. But when you play it back over software that
can do the core decoding – also called the first unfolding – you will get a signal up
to 96 kHz, if the original master was 96 kHz or higher. That signal can be sent to any non-MQA DAC
for conversion. That DAC will cause time smearing due to the
reconstruction filter it applies.
Like it does with non-MQA files. If you have a DAC that offers MQA rendering
and the master was at a sampling rate higher than 96 kHz, the signal gets reconstructed
to the original sampling frequency, even if it is 384 kHz. There also is a provision that corrects for
the time smearing of that DAC. But since every DAC has its own time smearing
fingerprint, the compensation circuit has to be specific for that type of DAC. Therefore software like Roon and Tidal player
can never perform this last step. If you own a DAC that does both phases, you
can even use normal – non MQA – player software or hardware like JRiver, Volumio, Squeezebox,
yes even Linn players to send a digital MQA file to a DAC that does both the MQA core
decoding and rendering.
You then get the same result as with core
decoding software plus an MQA rendering DAC. Of course with the limitations of the hardware
used. So there are three groups of DAC’s:
1: Non-MQA DAC’s 2: MQA rendering DAC’s that need software
to do the core decoder 3: MQA DAC’s that do the core decoding and
the rendering. Hence there are four possibilities when playing
an MQA file: 1: You have no MQA software or hardware: your
can play MQA files as if they are normal 44.1 or 48 kHz files. Time smearing in the recording is corrected,
the time smearing in the DAC isn’t. 2: You use player software that can do the
MQA core decoding, like Tidal player or Roon, and a non-MQA DAC: you get an audio signal
at the original sampling rate of the master up to 96 kHz.
That can be 44.1 kHz but also 96 kHz, depending
on the original master. Time smearing in the recording is compensated
for but you don’t get the time smearing compensation appropriate for your DAC.
3: You use player software that can do the MQA core decoding, like Tidal player or Roon,
and a DAC that can’t decode but can render MQA signals: both the recording and your DAC
are time compensated for so you get the best quality an MQA file can offer on your equipment. Examples of MQA rendering only DAC’s are
the AudioQuest DragonFly DAC’s. 3: You use a DAC that is able to do both the
MQA core decoding and rendering: Now your source, being a hardware streamer, a cd-player
or music player software on your computer that doesn’t need to be MQA enabled. As long as it can send out a bit perfect digital
signal to the MQA DAC, you will get the full MQA quality up to 384 kHz sampling, provided
the master was 384 kHz.
And both the recording and your DAC are being
time compensated for. Then about the cd-player: there are now MQA
cd’s as well, although I don’t expect this to become very popular. Streamers that are MQA enabled internally
normally have the core decoding done by its processor inside the streamer and then send
it through an MQA module to the DAC chip. That MQA module is then optimised for that
type of DAC chip. This is why the digital output of streamers
often output the core decoded signal, meaning up to 96 kHz sampling. Roon uses this to step approach to offer all
kinds of digital signal processing. Normally Roon sends out a bit perfect signal
to the endpoint. But the user can have the volume between tracks
of albums levelled out automatically. Or have equalisers applied to compensate for
shortcomings in the stereo or acoustics. It can even do sophisticated room connection
using the impulse response of the room to convolute a room corrected audio signal.
Before Roon became MQA compatible, using DSP
techniques would cripple the MQA authentication so you would end up with a 44.1 or 48 kHz
signal. But since version 1.5 Roon can not only do
the core decoding but it can apply all kinds of DSP functions while keeping the MQA authentication. This means that rendering DAC’s will do
the normal MQA level rendering while full MQA DAC’s will recognise it receives an
MQA Core signal and thus will switch to rendering only. So now room correction, cross fading and volume
levelling all became possible. MQA matters have been troubled somewhat by
a loud minority that screamed hell and fury but were very poorly informed. It was rumoured that MQA is copy protected. Wrong, there is NO copy protection in MQA. There never was an there will never be.
I have this in writing from Bob Stuart, one
of the two inventors. If I would mail you an MQA file, you would
perfectly be able to play it back. Only the quality at which it will be played
back depends on your equipment. You can play it back on your phone, on the
old 300 euro Stereo-in-a-Box system in the kitchen that doesn’t support MQA and on
your super duper MQA enabled stereo in your listening room.
Try that with a normal 96 kHz FLAC file. Chances are the latter will only play in your
listening room since the other two sets don’t do 96 kHz. Another argument used agains MQA is that it
is lossy, just like MP3. Incorrect. With MP3 sound quality over the entire audio
band is willingly decreased to achieve smaller file sizes. MQA uses lossless compression up to 45 kHz
bandwidth and uses a different way of storing the information above 45 kHz. Furthermore it uses bits that are not used
for audio to store relevant information in. Pure technically you could say that MQA is
lossy above 45 kHz. But there is no relevant information above
45 kHz, the only reason to use higher sampling rates is to be able to use milder anti-aliasing
and reconstruction filters. See my video “Is MQA lossless”.
There you will learn that when you consider
the entire chain, MQA potentially looses even less quality than normal PCM. Yes, there is a loud minority – mainly in
the computer audiophile community – that don’t like systems other than public domain. But big steps – like MQA offers – can never
be public domain. It took Linux over 40 years to become more
or less usable to the normal consumer.
Vinyl wasn’t public domain, CD wasn’t,
SACD wasn’t and so on. If you are not sure about MQA, just listen
to it. If you don’t hear an improvement, just stick
to the gear you have. And If you do hear an improvement, consider
if it is worth the investment. Inform yourself, decide for yourself and don’t
let the loud minority decide for you. To stay informed, subscribe to this channel,
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at home by telling your friends on the web about this channel. I am Hans Beekhuyzen, thank you for watching
and see you in the next show or on theHBproject.com. And whatever you do, enjoy the music.