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@eltech

 

I really don't know where to start, so I will just say that your post is one of the most lucid, logical and honest, I have read on this forum, so good in fact, that some will probably dislike you for saying it.

I am just glad you did.

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Of  significance to me is the fact that MQA were given plenty of opportunity to respond and have their response published. They declined to do so. If they had any belief or evidence that the article to be published contained false and misleading information or  compelling inaccuracies,  I have little doubt that they would have strongly denied the findings and supplied measurements of their own.  They did not.  Instead, they chose to allow their fan base to come to their defence and avoid having to admit to anything of a factual nature.

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21 hours ago, Sir Sanders Zingmore said:

I'll go first, FLAC.  Your turn (I'll give you a clue, it's got the word "lossless" in it) edit: I'm not sure what real  "issues" the MQA guys faced apart from deciding what colour to make the little light

 

Is flac encoded 44.1 lossless or is flac encoded 192k lossless?  Is a cable direct from the concert to your living room lossless?

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28 minutes ago, bhobba said:

 

Is flac encoded 44.1 lossless or is flac encoded 192k lossless?  Is a cable direct from the concert to your living room lossless?

Flac is encoded whatever it's distributed as... most of my flacs are 88.2/96/176.4 and 192k 24 bit and lossless.

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Guest rmpfyf
4 hours ago, LHC said:

Obviously Archimago believe in the first position, and from that point of view his arguments make a lot of sense. Obviously Bob Stuart believe in the second position, and this forms the reason for 'deblurring' in MQA. There is no argument over how filters and ringing work. The argument is whether the benefit of deblurring is audible, and the compromises of delurring are tolerable. 

 

NO no no no no no no no no.... not again, please. 

 

There is no one that believes the psychoacoustic limit is over 22.05kHz. The Nyquist frequency for this content is 2x this or 44.1khz. We cannot hear anything at the Nyquist frequency. 

 

Deblurring is a b******t word invented by Meridian. Please. This 'blur' is simply spectral leakage in the time domain. All digital filters leak around the impulse. This leak can be made smaller in time with higher sample frequencies and can be changed in time by modification to the filter. That's it. That's all there is to it. Yes, it's audible, not least because it creates a difference in the reconstructed time domain (which is the result exiting the DAC which we ultimately hear). Archimago ran some nice tests on linear vs minimum phase upsampling which had some nice skew towards minimum phase in the results for people using speakers. 'De-blurring' and filtering are not different things, it is just filtering.

 

MQA is a controlled format that allows nicer filters at higher frequency for certain content within an audio stream, and that can stack this effect to have layers of as much (for which they've pilfered the term 'origami') within the one file container. 

 

You would have to be listening to a very resolute system - which some of us have - and very specific content to notice a substantial difference. A scrunching paper demo would be a relevant example. 

 

Beyond that the format can be repurposed for re-mastering with an indirect form of DRM on quality. Re-mastering is audible no matter the format or frequency.

 

MQA does not have a mortgage on whether better, shorter-in-time-domain filters are audible. Hi res (to the point of mastering frequencies) do. 

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Guest rmpfyf
40 minutes ago, Sir Sanders Zingmore said:

Have you read the article? It's filters are not "nice". They are leaky with huge amounts of aliasing 

 

Yeah, I did. Nothing new.

 

As to what the filters are - depends how you apply them... just like any filter. That no filter gives a free ride in amplitude and phase is also not news. The article glosses over the point of MQA with the this:

 

"What this means is that given the same starting time, an 18kHz frequency component of the sound would actually be delayed by about 40µs compared to a 100Hz tone using that MQA filter on a 44.1kHz sample. Sure, we are only talking about microsecond differences, which would be significantly reduced with 88.2/96kHz material, but the point is that this was supposed to be a system that improved time-domain characteristics!"

 

Well, duh. And half the point of MQA is to store higher-frequency content within the same file container for - drum roll for what's been DSP for ooooo decades now - improved time-domain characteristics. Applying a min phase filter with a slow rolloff and comparing to to linear phase with a faster rolloff for material at the same sample frequency is going to reveal leakiness, huge amounts of aliasing, and absolutely nothing new. This is basic DSP, which is why the original takes on Redbook didn't include filters of this type. If you apply the filters at higher frequency, you get better time domain performance. 

 

It's also why some very nice DACs and other hardware giving choices of min phase apodising filters with relatively low passbands do it at ridiculously high frequencies (think 384kHz). Up the frequency, improve the time-domain characteristic. Nothing new. 

 

This notion of 'I can apply my deblurring to any material and it will change group delay in a likely shite way' is also zero surprise. There is really nothing new here. That Meridian is suggesting that there's benefit at the same sample frequencies is an example of the corporate greed p**stake Bob Stuart and others are trying to milk out of the audiophile value chain. 

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6 hours ago, Ittaku said:

Flac is encoded whatever it's distributed as... most of my flacs are 88.2/96/176.4 and 192k 24 bit and lossless.

 

It reproduces what it's fed - but is what it's fed lossless?

 

Thanks

Bill

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6 hours ago, Sir Sanders Zingmore said:

Have you read the article? It's filters are not "nice". They are leaky with huge amounts of aliasing 

It is very leaky - but the leakage is it reflects stuff above 48k to below 48k.   But if it is below 16 bits and they only transmit the first 16 bits it makes no difference.  I have posted the technicalities many times - see:

http://www.aes.org/e-lib/browse.cfm?elib=17501

 

Have a look at figure 10.  This is  the frequency  response of a typical recording after the sampling they use.  It introduces a slight filter that hardly does any ringing damage - have a look at fig 14 to see the large difference between what it does and the usual filters used.

 

Notice - at the frequency where the musical information is below the noise, and reproducing that is of no value, it is less than 16 bits.    This is the case excerpt for a very small number of recordings - MQA say those over 48k is much less than 1% - but they evidently use some secret tricks in that case to not loose the musical information.  Of course as time goes by with better equipment we are likely to see more recordings like this.   It's why I say MQA's true worth lies in the future.   The other thing the sampling used does is act as the leakiest possible filter you can get - its the same as throwing away every so many samples until you get 96k,  this causes those frequencies to be reflected back into the audio band - but since it below 16 bits its leakage is below 16 bits.  So transmit the first 16 bits only and you have transmitted ALL information - except stuff below 16 bits - with no leakage.  You can use a tricky thing called subtractive dither so the 16 bits is equivalent to more like 20 bits - likely more.   But 20 bits is about the thermal limit anyway so going below that is likely not of much value.

 

The question about lossless has a simple answer - no method s lossless - it a choice of the medium what issues you make better at the cost of others.  MQA has made the decision to reduce bit resolution but increase frequencies reproduced and reduce blurring caused by brick wall filters.

 

Now why does MQA polarize?  I don't think anyone knows for sure - but it seems likely its associated with the filters used to that sampling and the methods (called second unfolding) to try and guess those bits chucked away.

 

Thanks

Bill 

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13 minutes ago, bhobba said:

Now why does MQA polarize? 

it polarises because it's a lossy, leaky system that adds no proven sonic improvement and is a cover for DRM and some audiophiles are sick of the sycophantic pandering that's come from most of the hifi press 

Edited by Sir Sanders Zingmore
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Gee, there is a lot of hate for MQA in this thread.
Frankly, I'm not interested in the technical arguments. I just know that, when I am browsing Tidal, using my Bluesound Node 2, I find myself looking for MQA albums because they sound good.

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18 hours ago, LHC said:

 

There are a lot of details in this blog and his CA article. But fundamentally Archimago's premise is not new, and has been debated several times in SNA. There are two opposing positions one could take:

  1. Human cannot hear frequencies beyond the Nyquist limit; and the contributions of frequencies beyond Nyquist to the signal in the time domain are not audible by the human ear.
  2. Human cannot hear frequencies beyond the Nyquist limit; but the contributions of frequencies beyond Nyquist to the signal in the time domain are audible by the human ear.

Obviously Archimago believe in the first position, and from that point of view his arguments make a lot of sense. Obviously Bob Stuart believe in the second position, and this forms the reason for 'deblurring' in MQA. There is no argument over how filters and ringing work. The argument is whether the benefit of deblurring is audible, and the compromises of delurring are tolerable. 

 

I agree entirely!

 

It useful to re-read the assumptions of the axioms/hypotheses that Stuart et al make quite explicit in their patent application (WO2013186561):

Axioms

Most adult listeners are unable to hear isolated sinewaves above 20kHz and it has hitherto often been assumed that this implies that frequency components of a signal above 20kHz are also unimportant. Recent experience indicates that this assumption, though plausible by analogy with linear-system theory, is incorrect. Current understanding of human hearing is very incomplete. In order to make progress we have therefore relied on hypotheses that have been only partially or indirectly verified. The invention will thus be explained on the basis of the following hypotheses: - The ear does not behave as a linear system

- As well as analysing tones in the frequency domain, the ear also analyses transients in the time domain. This may be the dominant mechanism in the ultrasonic region.

- "Ringing" of filters used for antialiassing and reconstruction is undesirable, even if in the high ultrasonic range 40kHz-100kHz.

- Aliassing of frequencies above 48kHz to frequencies below 48kHz is not catastrophic to sound quality, provided the aliased products do not fall within the conventionally audible range 0-20kHz.

- A pre-ring is usually more of a problem than a post-ring, but both are bad.

- It seems best if the temporal extent of the total system impulse response can be minimised.

Regarding the last of these points, the "total system" is intended to include the analogue-to-digital and digital-to-analogue converters, as well as the entire digital chain in between. Ideally, one might include the transducer responses too, but these are considered outside the scope of this document. "

To me MQA lives or dies on these axioms - that decreasing the impulse/transient responses of the digital playback system as a whole improves the sound quality without other overwhelming negative effects.  So far my personal experience with the sound quality has been positive – and one would hope others would at least give it a fair/unprejudiced hearing as Wolster has done.

 

The other arguments against MQA seem to me largely irrelevant/red-herrings - the arguments against its partially-lossy compression because any distortion  (less than -80dB or 0.01%) produced is below the noise floor/distortions of most playback systems. And the DRM arguments because there will always be other choices – and I personally am willing to pay a slightly higher price if leads to higher sound quality. I find it interesting that people seem happy to spend up to $50 for a vinyl copy of a digital recording costing less than $10 – when the vinyl playback system will have distortions of around 1% and a noise floor of around -50dB at best!

 

As I have said many times before there is nothing new in the separate bits of MQA – nothing new in the frequency or filters needed to reduce ringing ie ‘blurring’ of transients that are an integral part of our appreciation of music along with frequency response and other distortion – all of which have to be compromised/balanced.  This lack of novelty was also shown by the International Search Report of their patent applications.  However it is their system as a whole that is new/inventive.  In particular it aims to reduce ringing/blurring in the system as a whole from ADC input to DAC output. 

 

One feature of this that is often forgotten is that it aims to compensate for ringing in the original (historic) ADCs by essentially applying an inverse convolution filter – a bit like DSP does to correct room standing waves by applying the inverse frequency response. This seems to me a very positive aspect - though some think of it as 'remastering' (I don't) and an attempt by the music companies to gouge consumers yet again. But you pays your money and makes your choice!

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A question - why did they aim low with MQA? Given the ever decreasing costs of storage and bandwidth, high res digital is becoming less and less of a burden and will eventually be completely irrelevant. If they're trying to create a future standard for mastering, why not aim to pack 26 bits into 24 or max out all 24 instead of aiming lower? If they're aiming to gain favour with streaming sites, the recording industry and consumers at large, it seems to me they're heavily putting emphasis on the producers rather than the consumers to "get in now". If they're aiming at the client consumers that want the highest quality possible, it's a group that has been steadily aiming/collecting 24 bit audio and now they're being told to accept 18. I don't mean to debate whether the 24 bits matter or not, but that lowering the target will automatically make the consumers wary and less accepting after spending years being convinced by the industry they needed more.

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Guest rmpfyf
17 minutes ago, Ittaku said:

A question - why did they aim low with MQA? Given the ever decreasing costs of storage and bandwidth, high res digital is becoming less and less of a burden and will eventually be completely irrelevant. If they're trying to create a future standard for mastering, why not aim to pack 26 bits into 24 or max out all 24 instead of aiming lower? If they're aiming to gain favour with streaming sites, the recording industry and consumers at large, it seems to me they're heavily putting emphasis on the producers rather than the consumers to "get in now". If they're aiming at the client consumers that want the highest quality possible, it's a group that has been steadily aiming/collecting 24 bit audio and now they're being told to accept 18. I don't mean to debate whether the 24 bits matter or not, but that lowering the target will automatically make the consumers wary and less accepting after spending years being convinced by the industry they needed more.

 

Because you remove bandwidth costs from providers and place an equivalent or greater margin on end consumers for a similar outcome.

 

In short you create a habit that's as hard to kick for consumers as it is for distributors. 

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11 minutes ago, rmpfyf said:

 

Because you remove bandwidth costs from providers and place an equivalent or greater margin on end consumers for a similar outcome.

 

In short you create a habit that's as hard to kick for consumers as it is for distributors. 

I guess in the end my question ended up being rhetorical and you gave a nice exposition for it.

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Guest rmpfyf
1 minute ago, Ittaku said:

I guess in the end my question ended up being rhetorical and you gave a nice exposition for it.

Oh I know it was rhetorical. I'm that unimpressed with MQA's licensing policy I felt a need to give it another kick :P 

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1 minute ago, rmpfyf said:

Oh I know it was rhetorical. I'm that unimpressed with MQA's licensing policy I felt a need to give it another kick :P 

Works for me. In many ways I'm glad the DAC I only bought a few months ago doesn't have MQA and I just keep buying hires digital instead.

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3 hours ago, legend said:

system as a whole from ADC input to DAC output. 

How do they do the ADC bits with existing recordings - almost all of which have digital masters. Are they reassembling the bands in the studios or are they just making that bit up ?

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How do they do the ADC bits with existing recordings - almost all of which have digital masters. Are they reassembling the bands in the studios or are they just making that bit up ?
Very droll, Sir Z.
Out of interest, have you personally had a good listen to MQA?

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Guest rmpfyf
3 hours ago, legend said:

To me MQA lives or dies on these axioms - that decreasing the impulse/transient responses of the digital playback system as a whole improves the sound quality without other overwhelming negative effects.  So far my personal experience with the sound quality has been positive – and one would hope others would at least give it a fair/unprejudiced hearing as Wolster has done.

 

Rod, 

 

This is not new and I don't think that anybody is reasonably suggesting that MQA, properly applied, cannot sound better in a shootout between two files capturing the same content vis-a-vis container sample rate. MQA allows lossy compression of higher-order spectral content allowing for more resolute time-domain responses where required, and some flexibility in filter choice. In lieu of playback distortions or poor mastering MQA played back with the higher-order content will not likely sound better than a master at that same frequency, as MQA is ultimately missing content. 

 

The rest of your post gives me no pleasure to read. Here's an example:

 

3 hours ago, legend said:

One feature of this that is often forgotten is that it aims to compensate for ringing in the original (historic) ADCs by essentially applying an inverse convolution filter – a bit like DSP does to correct room standing waves by applying the inverse frequency response. This seems to me a very positive aspect - though some think of it as 'remastering' (I don't) and an attempt by the music companies to gouge consumers yet again. But you pays your money and makes your choice!

 

This is not new, and it's not remastering either. It's linearisation of a time domain signal using convolution. Simple. It is not completely like what a DSP does by applying inverse frequency response for room correction, because in all likelihood the DSP in question had a person with a microphone taking silly accurate room measurements of the passive filter in question prior to applying it as a correction. MQA makes an assumption about the filter, and any error in this process - any error - will introduce group delay in spades. So will changing from a linear to minimum phase filter at the same frequency. Both of which it seems to do often. If this is a 'feature' it needs debugging. 

 

3 hours ago, legend said:

As I have said many times before there is nothing new in the separate bits of MQA – nothing new in the frequency or filters needed to reduce ringing ie ‘blurring’ of transients that are an integral part of our appreciation of music along with frequency response and other distortion – all of which have to be compromised/balanced.  

 

Filter response is not a compromise in an age of higher sample rate DACs and multiple filter choices. it is an engineering design criteria. You want that response nice and short? Build an upsampling DAC, run your entire chain at DxD rates or greater. There are DSPs that'll do that too, and again this is nothing new - industry is moving to 192kHz for most applications with some using filters with lower passbands at double that. 

 

3 hours ago, legend said:

The other arguments against MQA seem to me largely irrelevant/red-herrings - the arguments against its partially-lossy compression because any distortion  (less than -80dB or 0.01%) produced is below the noise floor/distortions of most playback systems. And the DRM arguments because there will always be other choices – and I personally am willing to pay a slightly higher price if leads to higher sound quality. I find it interesting that people seem happy to spend up to $50 for a vinyl copy of a digital recording costing less than $10 – when the vinyl playback system will have distortions of around 1% and a noise floor of around -50dB at best!

 

Come on. Name another current format that clips the ticket as many times as Meridian does with MQA and you can have that argument. Better yet - I'll agree with you. 

 

I have vinyl too and some of it is frankly a silly excuse for me to have a grand sense of occasion whilst I setup and remove the LP from a rig that'll ultimately drag a rock around a piece of plastic. But you know what? I own that experience. I paid for it. I don't get one experience, and then another one if I flip Bob Stuart and friends another $5, and then a better one yet if I spend a few thousand more on a deck they license too that'll light up blue when I've paid correctly. 

 

The 'other choice' is high res and the difficulty - which you don't seem to appreciate - is @davewantsmoore's point of there being other choices only as long as they're available. The MQA model is very attractive for distributors owing to the cost model it promulgates... namely less cost for distribution. Yes, this could be done in a market-fair and altruistic way but that's not the path Bob and co have chosen, with false claims around linearisation effects 'master quality' branding on what's essentially a light that says 'this is the best we can do, enjoy'... with threats of legal doom for any third-party vendor that tries to give customers back the content they've already paid for. 

 

We lived through 20 years of MP3 with a bunch of Germans getting rich off royalties for their work pre patent expiration without their needing to pretend it was something it wasn't, without needing to clip the ticket so often. No one believes good work doesn't deserve a reward. 

 

Ask yourself how so many other codecs did well in market, brought returns to their inventors and had near-zero hatred in market and why MQA is different. 

 

Clue: it's not technical.

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20 minutes ago, wolster said:

Very droll, Sir Z.
Out of interest, have you personally had a good listen to MQA?
 

The first part was actually a serious question - how do you apply MQA processing at the analog-digital conversion stage when that conversion has already happened ?

 

To your question, I've listened to MQA files streamed via Tidal and can't hear any difference. I don't have an MQA dac though so I'm just listening to the first decompression I guess 

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@rmpfyf

Can you please explain to me why a conventional oversampling filter  as used in most CD player and DACs is getting such negativity thrown at it?

 

My understanding is that the 0.001% ripple is at 22.5khz (inaudible) and it is -90dB relative to 0dB full scale.

This seems very good to me.

 

What is wrong with this, relative to MQAs filter?

 

 

Edited by eltech
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As I’ve already pointed point either here or somewhere else, I only really liked or didn’t mind so to speak, MQA till I got the Brooklyn. I didn’t like it on the Node2. 

So considering that, I’d like to know for sure if when listening to 2L tracks on the node2’s analog out, are you getting 352k like you do when using the Brooklyn. 

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Have been following this thread with interest. It seems that there are 3 groups, Yes, No and NEM.

 

Yes

 Have listened to MQA, believe it has improved AQ and willing to pay the additional costs. Some can argue on the technical merits. The ears have decided.

 

No

Have listened and found that MQA has not improved their listening experience. The ears have decided again. Argue on technical grounds that MQA does not have merit. May include commercial, marketing arguments. Archimago sits in this camp.

 

NEM (Never Experienced MQA)

The majority of people have not experienced MQA, and I fall into this group. 

 

It is unlikely that the Yes and No camp will sway each other; both have made up their minds. It is the NEMs that need convincing because it where the majority of people are and where future revenue come from.

 

Here is one NEM's thoughts. I am befuddled by the technical arguments. I am more worried about the commercial impact on the digital audio chain and how can it be exploited to the detriment of the consumer. While I support fair payment (and have paid for my music),  the music & audio industry is full of stories of greed.

 

I am yet to be convinced to try MQA, let alone open my wallet. Why not try it?  I may yet like it but then would have to fork out for new equipment and MQA encoded music. Not sure I want lock in into a closed expensive ecosystem?  :(

 

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