On my digital side I have an Aurender W20 server with a Metrum pavane level III DAC.    When I stream music I am using the HiFi TIDAL. The Metrum has an option of purchasing a card that I would install to add MQA capabilities. From what I have read there is some controversy as to whether MQA is a positive or negative to the sound of digital. I was interested in thoughts on whether I should add the module. 
IMO all depends on quality level of rest of your system. 

Speaking from experience with full mqa across 3 systems, it is only my main system where I can appreciate the sonic difference of mqa. But the difference on that system is substantial and well worth price of admission for me. I gravitate to mqa albums there because noticeably improved quality. 

But it on my second and third music systems (roughly $3k and $1k total each) I can’t necessarily hear the mqa difference. 

That’s not to say results would be same for all systems in those price ranges, but just my experience with my stuff. 
 Thank you for the input. The system I am looking at installing the MQA module in is a very high-end system. It is very transparent. 
aside from various MQA controversies, some like the sound and some do not.  I would think you could get the card with return privileges. You will not get any agreement here as to whether it's any good, and thats irrelevant anyway...
@rbodner I can’t imagine you would hear much of a difference at all since you are working with their top of the line DAC. I run the Onyx with the Ambre and do think MQA sounds better on some albums compared to the normal 16/44.

I thought about adding the card, but Anjo @ Metrum told me not to waste my time and let the Ambre take care of the unfolding even if it’s no the "full" unfold.
I can’t imagine you would hear much of a difference at all since you are working with their top of the line DAC.

Can you explain? Thanks. I think this explains it fairly well.

"The second unfold corrects the impulse of the digital to analog converter as well as extracting the fine temporal detail of the original recording. This process is tailored because every single DAC has its own behavior. This is most beneficial for oversampling DACs that use steep filtering. The DAC’s oversampling filters are always applied just “above” the music and have a negative impact on the impulse behavior. To solve this, one can use their own up-sampling technology to push the DAC’s steep filtering up to higher frequencies. As a result the DAC’s filter is being detached from the music and causes less disturbance to the music. Gentle up-sampling can also create artefacts, but these are generally considered less annoying than steep filtering.

"Now let’s talk Non Oversampling. Per definition a Non Oversampling digital to analog converter does NOT use any filtering and is entirely focused at the perception of the human ear. As NON Oversampling DAC do not use any filters, in combination with MQA Core Decoder (first unfold), a NON Oversampling output will only benefit, and this is the case with every single DAC in the Metrum Acoustics range."  

I read that as the 2nd/3rd unfold for MQA is more beneficial to OS DAC’s.
@justjames72 Does the 2nd unfold happen prior to NOS/OS? In other words, does the DAC conduct the 2nd unfold and use that information as "native" and then apply oversampling, if selected? Thanks.
Unfortunately I'm not that well versed to be able to answer that without just guessing. 
Thanks. It would be good to know if the second unfold is presented as 'native' and oversampling (if applied) occurs after this 2nd unfold.
I have a system that’s very resolving and detailed. MQA is noticeably different from my digital through my Yggdrasil. To me MQA is a different flavor that’s very enjoyable. In my setup I find MQA to be a bit laid back, a bit more spacious (kinder, gentler). Doesn’t rock like digital through the Yggdrasil which I also really enjoy. It’s a very enjoyable addition to my listening options. I was not sold on MQA until I had it for a few weeks. Now I would miss it if I didn’t have it. I read about all the unfolding stages etc. it really just came down to listening to it for a while. Hope this helps.
Rbodner, since you have a high level system, I am sure you will be able to hear an improvement with MQA. I only have an Aurender N10 streaming into a Berkeley Ref 2 MQA Dac with Tidal MQA and I prefer MQA over CD quality every time.
Qobuz has hi res, that doesn't need MQA, I have both and on many similar albums, I prefer the Qobus over Tidal with MQA. But that starts the argument about library size and ease of interface, etc. But I also feel that MQA is worth the price of admission, moderate improvement over standard Tidal streaming on a very resolving system.
I can’t imagine you would hear much of a difference at all since you are working with their top of the line DAC.

Can you explain? Thanks.
I'm totally baffled by this too...Not saying I know MQA is good, bad or indifferent but i just don't follow the logic.
Hans likes MQA and I trust him.  But there's so little MQA out there, and the self selection bias on MQA releases distorts most opinion.... wish i could say more aside from "listed and decide if it makes you happy"G
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@itsjustme baffled by what? Maybe, I can help clarify my understanding even if it's not as robust as some. 
Well, i don’t even know what to ask. So I’ll ramble.
Let’s put aside the real discussion which is the basic merits of MQA, and accept it for what it claims to be; an improvement in digital coding ("better HD"). Not playback mind you, coding. Bob’s a smart guy, I do presume that there is something to MQA, but that's my opinion.

We will assume that HD differences, if they are audible, will be audible on better systems.

Yo note the OP has a top flight DAC. So that seems to be a good foundation for a appreciating HD coding, and specifically MQA. Again, MQA may be total BS or music’s savior - it doesn’t matter for now.  But how on earth does having a good system make good source material less relevant?
Heck, I’d argue that all this talk about equipment misses the point -- the big differences are in recordings, masterings and pressings. And in rock, the state of the art has been low.
I should add that I have not heard MQA in my system or any system i know and trust, nor in a well controlled comparison (any offers in the Morristown-Summit corridor?). All 4 of my DACs do not support MQA. One's 20 years old (and still excellent BTW), two are Franken-DACs either of my own design or vastly different than originally built, and one is the new Denefrips which i have not yet heard (or seen).  So MQA is not on my near-term radar.  Honestly wish it were, out of curiosity if nothing else.
@itsjustme so maybe you didn’t read my further comments, but I’m a fan of MQA and also have a Metrum DAC (Onyx) <no MQA card>. My point is that the 2nd/3rd unfold of a MQA DAC maybe less relevant with high level DAC’s especially NOS(non MQA) ones.

He’s getting the first unfold of MQA with Tidal HIFI. My argument is that he may not hear any difference at all if he was to get the MQA card for the Pavane.

I spoke with the CEO of Metrum and he said not to bother with getting the MQA card for my DAC (Onyx), so I would assume he would suggest the same for the Pavane.

The whole MQA thing is very confusing to begin with and sometimes I feel its that way on purpose, but I listen with my ears, not my eyes and MQA on many songs sound great in my system....Roon >Metrum Ambre- Onyx> McIntosh MA6600
I do understand why you might think that logic doesn’t make sense, but I’m thinking the final unfolds in MQA are more effective with lower tier DAC’s. The higher tier esp NOS don’t have filters, so a lot less "noise" to remove.

That’s how i understand it at least and I could be wrong.

I suppose I should also state this. My previous setup was Bluesound Node 2i with a Rotel 1572. The Rotel’s DAC is not MQA compliant, but the MQA tracks playing through Bluesound to the Rotel DAC sounded better to me and I know i’m not the only one who has done this comparison.

We are talking about different DAC’s of course AKM vs Bur Brown and that could just be my taste, but I’ve read other people’s comments on the internet that said the same thing. You would think the bluesound node with a MQA DAC would sound superior to a non mqa DAC, but that wasn’t the case in my setup at least.

Hope that helps to clarify, but I may have confused you even more ;)
Data points are always good.
The unfolding however, is reputed to be much more than filtering.  Its proprietary so we cannot say for sure, but they claim that additional resolution and time coherency are restored. This is why i used the terms "coding vs playback". Its vague, but so is Bob on this point. It's his secret sauce.

(specifically i wrote: Let’s put aside the real discussion which is the basic merits of MQA, and accept it for what it claims to be; an improvement in digital coding ("better HD"). Not playback mind you, coding.)
And no, i did not read your later comments at the time, never got that far, and thanks for the pointer.

Here is a 'How It Works' Overview from MQA:

A Steve Guttenberg interview with a Tidal Representative on MQA:

An early 'primer' from Michael Lavorgna:

I was first respondent here and mentioned I could hear major mqa positive difference on my reference system but not on my two secondary systems.

For context, those systems are:

Reference: Teac NT-505 (AK4493) -> MIT matrix 6 XLR balanced IC -> Audio Research DSI200 integrated amp ->MIT matrix 12 speaker cable -> Spendor D7, REL S5; Audio Art power cables. Here, MAJOR sonic MQA improvement streaming Tidal vs regular flac Tidal stream over cat7 Ethernet.

Second: Integra DTM-7 (AK4438) -> MIT Terminator 4 speaker cable -> Spendor SA1, Sunfire SDS8; WAudio power cables. Here, extremely marginal if any noticeable sonic improvement steaming mqa Tidal vs flac Tidal over WiFi.

Third: Bluesound Powernode 2 (Burr Brown 5122) -> AmazonBasics speaker cable -> NHT C-1. WAudio power cable. Here, extremely marginal if any noticeable sonic improvement steaming mqa Tidal vs flac Tidal over cat7 Ethernet cable.

So that gives hopefully some context to my “rest of system” comment. My two secondary setups are pretty modest but the source for each fully supports mqa so I can make the comparisons.
@kren0006 curious if you had the TEAC before the firmware update for MQA? Did network player have the software for MQA already and the firmware just updated the DAC?

It would be interesting if say, only the streaming side of things was MQA complaint but your DAC wasn’t if there would be a difference in sound quality. That's the point of debate right now.

However, that seems like a really nice DAC.
Hey, sorry I don’t know answer to that question re Teac dac.

i got mine and ran it awhile without the firmware update but wasn’t really focused on the question at hand, more really was just fumbling trying to get the fw updated (doing so not as easy with most modern hardware). But yeah, I really like it. 
MQA is a marketing ploy. No one needs it, but since it generates lots of profit it won’t die. There is no issue streaming hi rez files anymore. That’s the problem MQA is supposed to solve. So to continue the ploy they tell you that compressing the data and then decompressing it with their special technique somehow enhances the sound quality. It’s now better than the original. They can’t prove it, but people somehow believe it. And billions will be pocketed by the people behind MQA. Yes, I’m jealous I didn’t think of it first. 
MQA just adds distortion. The original full resolution version of any digital file (same master) always sounds better because they are lossless. MQA claims are entirely false.
@vinylfan62 my favorite is the people like you...Are you really that bored in your mom's basement that you feel that need to chime into a discussion you have no part in?? You're lucky I'm giving you the time of day....dork....what else do you have to say???
@shadorne do you guys both share a room together? 
I confess I have no idea whether MQA itself is good or bad, but my only music source on all of my systems is Tidal streaming, and so therefore the only way I can hear music above FLAC quality is via Tidal Masters which necessarily involves MQA. 

So I guess technically I should amend my comments in this thread that what really sounds good to me on my reference system is Tidal Masters via MQA, whether or not the MQA itself plays a positive or negative role in the music rendering.  Either way, definitely better than straight up Tidal 16/44 flac for me on my main system.

You can’t dismiss the facts by attacking the messenger. MQA adds distortion. This is a fact. Only the original lossless file has the full bit depth and correct phase preserved. MQA is both lossy and adds phase distortion (high frequencies delayed with respect to lower frequency content). These are facts.

If you prefer MQA over lossless files then so be it. There is no accounting for preference - it is entirely a subjective evaluation.
David Ten- I've seen all those and heard Bob speak on it.
None of those have technical details nor methods. They have concepts.  I'm OK with the concepts, but cannot honestly say i truly know exactly what is being done in the final unfold. That's why its burned in silicon and licensed.
Just sayin.
You can’t dismiss the facts by attacking the messenger. MQA adds distortion. This is a fact. Only the original lossless file has the full bit depth and correct phase preserved.
Be very careful here.  Lossless what?  Most lossless files don't even attempt to capture the extra resolution as does MQA. SO its not a valid comparison in all cases. You don't specify enough to know whether your statement, as you intended it anyway. is correct or not. As written its pretty shaky.
Now, as to phase coherency - this is a huge issue.  Is it correct in a recording after anti-aliasing filters?  I would argue no. The lossless hgih res file (or otherwise) preserves what got through the filters, which may or may not be correct. If betting i would generally bet on "not correct". So lossless then would preserve distortion faithfully.
Einstein quipped that things should be made as simple as possible but no simpler. We have violated his advice here.

@itsjustme  That post was a general and generic one and not directed at you. Agreed on the point you make.

@rbodner  The module lists for $250 with free shipping. Why would you not try it out??? Given the level (and cost) of your front end (Aurender W20 and Metrum Pavane Level 3) I would,.... just to get a feel for it's contributions.

I'm doing the same with a new board for my DAC and it has been an illuminating experience. 
David_ten - thank you for the references on MQA and it’s origin and inner workings. 

Vinylfan 62 and shandorne - OMG - digital music is here going forward. It has been a dramatic improvement over vinyl. Tidal HiFi with MQA has caused me to retire my Thorens turntable with SME tonearm (multiple cartridges). I still use two CD players in my two systems, as I have a large CD collection.  Tidal HiFi withMQA thru my LUMIN D1 has much better detail, lower noise floor, tighter base, etc. 

Progress is hard on people stuck in the 70s. 

In this hobby - your ears are the final judge - it is your money - but calling MQA claims ‘false’is over the top!! In my two systems MQA has given me better sound vs. analog compared to a live performance - IMO.

Happy listening!

@david_ten Thanks for you input. I am definitely leaning towards getting the module.

F/U Question:

Some of the technical aspects are confusing to me.

Do you think playing an MQA file from the server sounds different than a standard HIFI file even if the DAC doesn’t have an MQA converter/module?

There are multiple unfolds of MQA. Again, staying out of the debate on its merits, and adhering to its claims, there are some benefits without an MQA licensed decoder chip.
and @david_ten  - yes, i understand. I was just placing a generic caution that while that is all good reading, no one could build the chip (meaning understand how it really works) form what is published.
That of course is on purpose.
As a professional, credentialed, full time mastering engineer ... MQA has no credibility, no honor, as they have bulk processed thousands of titles to create a market, where audiophiles can get their 2 cents in to vote and to buy or not. MQA adds subtle harmonic distortion, and it’s offensive to a great mastering job, counter to the approved work of the artist and producer. If the mastering is a bit lacking the harmonic content can sound "better" to you, yet you are further from the approved master, not closer.  The issues of PCM if any exist, are not bulk processed, that is just creating other issues.  Common sense.  Very few titles are previewed and worked through the MQA codec as advertised, and you have no idea where these are because the list is a tiny percentage of what they sell. Buying or streaming the native sample rate of the mastering session is the BEST QUALITY. There is no upgrade, ever, full stop. For real, just stop dreaming. All the rest is marketing and lies. PCM was all that was needed said Bob a few years before he ran out of money selling DVD players in a streaming market. The decision here is not about sound quality, it’s about supporting charlatans, or letting them move on to other careers. MQA is running a 50 million GBP debt last I knew so let’s hope the greed dies and common sense prevails. Enjoy your listening !
You might consider enabling MQA, by paying, at the level of Aurender W20. I did it on mine and it works like a charm !
Like adding A-1 sauce to prime grade beef, the chef just rolls his eyes heavily. 
The very fact that almost everyone concedes that some enjoy the MQA difference and some do not effectively designates this technology to a category other than general improvement.

For those that enjoy the difference, perhaps the sonic change they hear was something their system lacked in the first place and could easily be achieved by a rebalancing through non MQA means. 
I’ve only tried a couple of MQA albums and after long listening to both, I am not inclined to buy any more.

Using the same recordings, I can certainly tell the MQA versions are different, but not any more "real" (which I know is subjective unless you were in the room during the actual recording).

In fact, if I had to describe a characteristic of MQA, I think they sound somehow more artificial. I’d be hard pressed to say exactly why I feel that way, but I kept coming back to that description during my listening.

The entire hobby / pursuit falls into that bucket....

The very fact that almost everyone concedes that some enjoy the MQA difference and some do not effectively designates this technology to a category other than general improvement.

Simply remove "MQA" from your statement:

The very fact that almost everyone concedes that some enjoy the difference and some do not effectively designates this technology to a category other than general improvement.

I have enabled MQA on my W 20.    From what I am understanding above even without the  MQA module in my Metrum there Should be a sound difference between MQA files and non-MQA files  I am going to listen to several albums in each format and see if I can hear a difference and which type of file I prefer. It would seem that could possibly help me decide whether I want to have the MQA module in my DAC?
I have a Bluesound Node 2 with full MQA decoding and my experience has been like some others. When I feed the Bluesound into my Marantz Dac it sounds better to me that way than using the Bluesound with the full MQA unfolding.
Who woulda thunk? Reckon I’m kinda lukewarm on MQA. 
@headspace but what about when you listen to the song not in MQA? do you notice a difference when using either DAC? 
Yes. I find I prefer the sound of the Bluesound ran through the Marantz ND-6005 whether it’s a Tidal Master or not. Everything just sounds better to me that way. I even run my Oppo BD-103 through the digital connection into the Node 2 and then through the Marantz when playing CD’s. Everything sounds better. Must be the CS4398 chip and the implementation of the HDAM in the Marantz? It gives it a warmer sound and a deeper soundstage than the burr brown Dac in the Node 2 at least to my ears. I’m certainly no technical expert on any of this stuff but I think I hit on a pretty good combination for my budget. I also get the flexibility of using 2 music streamers in my system. 
@ justjames72 asked:

@itsjustme baffled by what? Maybe, I can help clarify my understanding even if it's not as robust as some.
Baffled by why on would think that MWA, which changes the actual coding, would nto make a difference on a top-line DAC (but, unsaid but implied) *would* on a lesser DAC. Different music, different results. We may like it, may hate it, may think is nothing. But the quality of the DAC should be largely irrelevant - or have the opposite effect -- making it possible to hear subtle differences.
Sorry to comment a million years later, but i just saw this.