DACs mostly don't.
But if you have everything on hand you can do the capture.
The filtering can be done in different stages, mostly it's in the DAC. Some does it in XMOS DSP.
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MQA Deep Dive - I published music on tidal to test MQA
- Thread starter GoldenOne
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But if you have everything on hand you can do the capture.
The filtering can be done in different stages, mostly it's in the DAC. Some does it in XMOS DSP.
KSTR
Major Contributor
No. That would require a huge amount of bandwidth. The digital filter ususally operates at 8x or 16x the input sample rate because that's the whole idea of it ;-)
Here on ASR we do care. We take the claims of manufacturers, measure and test their products, and see if they live up to their claims.
Just enable 384/352.8khz input on XMOS.
This whole thread is quite strange I think, and very infected by strong emotions. I have now read from the beginning (but not all the way to the end) because I wondered how it derailed and who actually said what. An early reaction was that I thought much of the criticism of @amirm was in fact unfair. But after a while it also strikes me that it's probably really about something else. The argument about MQA reflects that there are strong feelings involved in the issue of pros and cons of MQA. As I see it, the argument is on several levels. It's only partly about MQA and sound quality. But at the bottom I think there is a completely different thing that is about who has control over what. The most critical fear that MQA is ACTUALLY about something completely different than sound quality. MQA is considered a form of DRM and revenue generator that is introduced under false pretenses of being something else. It must also be said that MQA themselves have really managed to incite that kind of suspicion with their lousy misleading marketing, their secrecy and their often incomprehensible comments and explanations. Fair criticism or not, I think that's the way many have perceived Bob Stuart and others behind MQA. But if someone says then, we have Blue Ray, Dolby and several other licensed codecs, what's so special about MQA? I think you have to see the issue in its context when it comes to music. There is a rather sad history around DRM and copy protection, where large companies have secretly installed rootkits (eg SONY), when purchased CDs have not always been playable in all CD players due to copy protection, hassle in various ways with making things work. ETC. I think those who have been involved in music and sound reproduction and who have experienced this, sort MQA into the same category. This is why many are outraged at @amirm or others who declare neutrality. Being neutral is not OK when something is perceived as a threat. Hence all invective and personal attacks. Anyway. I think this is a bit simplistic at the bottom of this infected discussion. When it comes to music, unlike film, it has largely been characterized by open formats, or relatively open formats. All attempts to date to lock in music in licensed formats, or non-open formats, have been moderately successful at best. Companies that have chosen locked exclusive formats have, as I have understood it, in fact lost market share. Therefore, I think that MQA can only get really wide acceptance if it is done openly and freely, but maybe not even that helps. I see no direct benefits with MQA, and in the long run consumers are usually uninterested in technology that does not provide an obvious advantage. And the real HiFi nerds are such a small niche that it does not matter so much. Personally, I have no strong idea about the possible advantages or disadvantages of MQA, but I am skeptical. I'm very doubtful if it has any advantages, at the moment it clearly has some disadvantages I think, but it probably has no future, so MQA does not make me very upset. Especially not as I can now opt out of it by subscribing to Qobuz instead of Tidal.
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BrEpBrEpBrEpBrEp
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Honestly, I don't find that too unreasonable overall. If Amir was going to remove himself from the conversation in a new thread, it only makes sense that others should not be allowed to crucify him in absentia, so to speak.
At the very least, this puts paid to the "shilling for MQA" conspiracy theory - he'd be a pretty poor shill offering to drop the subject altogether.
Raindog123
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I have access to and the capability to program a number of modem - FPGA/SoC plus DAC - development boards. At any bandwidth relevant here (and beyond). Mostly Xilinx (eg, large UltraScale+) with Vivado tools (and GHz-class DACs). If I'd get access to a [MQA] decoder SW (FW), I can do pretty much anything with it, very quickly and efficiently.
I have no idea what it might take (or even if it is possible at all) to get the source 'for evaluation & analysis' purposes... But if there is anyone (@mansr ?) out there who sees the point, let me know and we'll discuss...
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What about other forums where you comment about this, which Amir and others have screenshot in this thread?
Have you added update on all other forums, correcting your comments?
LOL this is the best thread. Just got even more entertaining somehow
Good job on taking up this challenge.
None of the tests here on ASR are that rigorous.
Sure. If the source is higher resolution than 16/44.1 (likely scenario), the MQA uses noise-shaping and subtractive dither to produce higher dynamic range. It can use subtractive dither because it is a closed, end-to-end system unlike CD (created by one system, played by countless others). Based on encoding setting, some of the extra spectrum can also be embedded in the 16 bit MQA bit stream. This is all documented in Bob's blog, albeit not in easy to understand package. We would need to design tests to verify how well this works and what the impact of encoding parameters are (likely a trade-off between worse quality unencoded MQA vs better quality decoded MQA and vice versa).
In many cases documented here (including Neil Youngs experience), that is not the case. We don't know how many of the MQA files on Tidal actually are based on better than CD "masters", so "likely scenario"? Don't really know.
No, it is not. If you put too much load in your truck bed, it will break the suspension and that is that. It is your fault for exceeding its spec.
That's exactly what it does. And works if you feed it music with distribution of huge sample of musical clips. Feed it stuff that is not music, and what it does is generate errors and create something. It is your job as an operator to examine what is going on and deal with it. One option would be to not encoded it in MQA. Another would be to change its sample rate. Or filter. That is why they provide a tool to mastering houses.
I don't know what you are talking about. MQA's output is constant bit rate unlike FLAC. It has to generate either 24/48 kHz or 24/44.1 kHz. Unlike Flac that can spit out massive files if it can't compress something, MQA has to fit things in that budget. It can do so for huge library of music. If it can't, then it can't.
Question has nothing to do with Tidal. It was about mastering MQA CDs. Physical media at mandated 16 bits, not the normal 24-bit files MQA produces for online distribution in Tidal.
As to Neil Young, I don't care what he said. He didn't conduct any controlled test to show that his content had degraded, or even changed.
Raindog123
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I hear you... Yet, while not available in commercial digital-audio implementations, this - the huge amount of bandwidth (processing and communication) - can be arranged, see my post above... Let's all think about if/how we can orchestrate this.
So their premise is broken. It cannot be lossless, or better than lossless. Broken.
Are you listening to explanations or just repeating talking points? Whoever is doing the encoding is a mastering engineer with many tools. If the entropy of the file is too high, he can reduce that, so that what is encoded in MQA fits.
If you feed it a full spectrum of random noise to 44 kHz, no, it can't encode that, nor is it broken since their customers are not asking for such an application.
A lot of these discussion are about Tidal and its use of MQA.
He didn't need to. He found out that the MQA files where not masters, and were not "as the artist intended".
Raindog123
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