Just found this on SBAF:
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Haha, it definitely “brings up” the mids (and bass) if the high treble is rolled off.
I think tube amplifiers have a similar effect, but imagine if you unknowingly combine that with a DAC similar to this. The effect will be doubled and you will start having the misconception that this is the reference sound and everything else sounds “cold” and “lifeless” 
Scary stuff…
Oops, apparently not. Just another myth floating around. Filterless operation is just wrong DAC functioning, allowing aliasing products from the sampling process to be reproduced at the output together with the useful signal (in other words allowing garbage to be added to the signal).
But it might be true that you need much higher sampling frequencies than 44.1 kHz in order to reproduce all the ultra-fast transients that can be detected by human hearing, according to some studies. If it’s true that we can hear transients as fast as 5 microseconds, perfect reproduction would require the presence of 200 kHz signals, which can only be achieved with 400 kHz sampling rates. I guess this might be the legitimate reason 386 kHz hi-res formats exist. The question then is how much music actually contains such fast transients and how much audible benefit could be obtained by the listener, considering also the frequency reproduction limits of the transducers we have on the market today (I’m not sure even TotL planars these days can actually reproduce 200 kHz transients; maybe electrostatics are the only ones that get close).
And how that study defines “detection” of such frequencies by human hearing? Because you certainly don’t have the hair cells inside the inner-ear for that. We don’t even have them anymore for up to 20 kHz, I don’t even need to think about 200 kHz.
Pay attention: we don’t detect frequencies, i.e. continuous sine waves, past 20-24 kHz, we can detect fast transients that are made possible by the presence of ultrasonic frequencies. Transients are one-off/sporadic phenomena, not periodic like a sine wave. We are much better at discriminating one-off events than constant/fast-repeating phenomena (presumably because of the requirements of survivability and how environmental threats usually produce one-off warning signals rather than continuous sine waves).
You can find the studies starting with reference [56] in this AES paper: http://www.aes.org/e-lib/download.cfm/17501.pdf?ID=17501
For example: http://boson.physics.sc.edu/~kunchur/papers/Auditory-mechanisms-that-can-resolve-ultrasonic-time-scales.pdf
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Donno, in those papers there is no definite proof I am looking for, it’s just the submitted result of some independent research. I bet that for every one of those there is another 3 papers saying the opposite. On top of that, they question the viability of higher sample rate formats, but they themselves admit that most of those problems are taken care of by over-sampling, a process that all but the cheapest DACs today should implement.
There needs to be a much higher scale experiment and actual full-proof findings widely accepted by most experts in the field before I replace my ~115 GB music collection with a “hi-res” one of ~450 GB. This reminds me of that research on the “hypersonic effect”, to which they didn’t found any proof some time later. It’s a lot like the subject of those papers and it’s not considered “controversial” for nothing.
There is even a video on the pitfalls of independent research with a small pool of test-subjects.
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Independent from what? He’s a university professor, he’s independent from exactly what he should be independent from: the audio equipment industry. 
And those are not just submitted, I can see 2 papers reviewed by other experts, accepted and published in scientific journals here, among his other presentations at various conferences and such: Information for prospective students
But it’s true that 2 studies by the same main author are far from enough to establish a new bulletproof theory. This will need to be independently replicated several times by different research teams, of course.
On that I have to admit I have a lower standard of evidence: if I can find some examples of 24/96 music that I can reliably distinguish from their 16/44.1 versions in a blind/ABX test, I will already seriously consider buying all my future music in 24/96 and looking for 24/96 versions of stuff I already own. 
But I probably won’t have much success, as hi-res these days is only applied to pretentious classical/jazz “audiophile music” that I don’t really listen to.
That’s an awfully low standard, considering that human hearing is incredibly prone to placebo from all sources. Your emotions or even your tiredness can drastically affect the sound of a music file you listened to 1000 times before. Also, this is from my own post a bit above:
Even reputable sources have an incredible amount of hoaxes and fake hi-res that contain nothing but noise in those upper frequencies. But since most people just believe their ears and don’t question spectograms like I do, it just works, since no one can ever hear the recording noise at those frequencies.
I think I found more “hi-res” files that had just noise or absolutely nothing at those frequencies, compared to those that actually had something that could be passed as music, to a creature that can actually hear it.
They’re going to get sued soon, then.
By the way, I got one new pair of headphones and one new pair of earphones this month, and I didn’t knew 320kbps mp3s could sound this good (Hearing the differences between mp3s and wav files is easier now, too).
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Mp3s are a subject I stood away from since I know they are controversial for most people, but I know the intricacies and engineering behind them and I consider them very good. I appied the same technique I used to see the absolute bit-by-bit difference between a hq 320 kbps mp3 and a standard lossless and the difference was mostly in unintelligible static noise. I repeated the test with other files and the findings were similar.
Conclusion: Just because a lossless file is a container 2-4x times larger, it doesn’t mean it holds 2-4x times as much audio information. It’s just a less efficient container.
And the mp3 compression algorithm doesn’t get rid of audio information indiscriminately. It’s based on a full-scale research completed not too long ago that indicates which sounds humans hear when they listen to a lot of them at the same time. A HQ mp3 will only target the inaudible parts of the music.
And for this reason, if you were to take a lossless file, convert it to mp3, then back to lossless multiple times, no extra information would be lost after the first time. Proof that the algorithm is not indiscriminate.
Overall, 320 kbps mp3 is a format that I trust. I will grab any music in lossless if I can, but if mp3 is the only option available to me, I won’t mind getting those as well.
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That’s why I said ABX.
Not sure that’s terribly relevant. In a fast-switching ABX test being tired would probably make me fail to spot tiny differences even if they were there, so I would end up leaning toward the cheaper option - sticking with CD-res. 
Oh I know, I just read one of Archimago’s articles that talks about that - I would have to check all that of course, I’m not going to pay HD prices just to get larger files padded with noise.
But right now I’m still sorting out the theoretical part - some people seem to think they have technical arguments for why Kunchur is wrong about the 5-us limit, and I have yet to see any substance to that claim. The debate continues.
You can’t just trust the files they provide. In order to check for sure, make a 44.1 kHz file from a provided hi-res. Then test the two and the differences between them are exactly like in my first post: the area bellow 22.1 kHz is completely identical.
For me it’s not an argument. I know fully the engineering behind the digital audio. I won’t be convinced by “feelings” and “it just sounds better” at this point. Right now I am just spreading knowledge to people that still believe in “stair-steps” and other similar non-sense. Of course if someone won’t understand the logic after all of that, then it’s impossible to convince them. But spreading some awareness should help a bit.
“Inaudible” for most people and most “consumer-grade” equipment. Not for most of us in this forum talking about the differences between DACs and amps, and searching for details, and knowing the meaning of “plankton”.
Also, everything is “unintelligible static noise” if you remove, uh, all the music from the data. Take an original track versus the remaster you love, remove the original track, and “unintelligible static noise” is all you’ll get anyway… This is useless.
I am just telling you the results of my research, it’s not like I am telling you to force your ears to listen to mp3. I also don’t like to romanticize digital audio, it’s just about numbers in the end.
Besides, the difference I talk about is quite absolute. If the files differ just by more than a tiny bit, then combining the inverted tracks to find the difference will just result in both of them playing at the same time, since there are almost no absolutely identical parts to cancel each-other out.
I presented the method in my fist post, you can make one when in doubt at any time using just free software.
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I’m absolutely still buying CDs, whatever anyone says. 
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Yep, he’s wrong, or rather his study was not designed well enough to demonstrate ultrasonic hearing: when eliminating the possibility that the discrimination was made on loudness rather than ultrasonics he used an outdated and overly generous threshold of loudness detection, i.e. 0.7 dB at 7 kHz, which newer experiments show to be much lower. So it’s not clear his subjects detected ultrasonic differences rather than loudness differences, his hypothesis remains unproven, and with it the supposed benefits of filterless NOS DACs.
In unrelated news, here’s another myth going around a lot: “you should keep your digital volume at max for best quality”. Nope, there are bad things that sometimes happen during the reconstruction of the True Peaks from compressed audio, which can lead to clipping if you’re always at max. Better to stay around 80-90% digital volume. From a long and boring article on Archimago’s Musings: Archimago's Musings: GUEST POST: Why We Should Use Software Volume Control / Management by Bennet Ng. (Plus discussions on resampling options, true peaks, etc...)
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This is interesting too:
As a “mere mortal”, just how many dB’s of dynamic range do we think we “need” anyway to experience the pleasures of “high fidelity” audio? Mitch Barnett (aka mitchco on Computer Audiophile / Audiophile Style ) published an experiment on himself back in 2013 where he demonstrated his audibility threshold at around -70dB using some dynamic rock tracks. I tried a similar test awhile back and I scored about the same. I highly recommend all “golden ears” to try the experiment themselves. You might be humbled at just how many “bits” of resolution you really can appreciate.
The funny thing about all of this is that it absolutely doesn’t matter. Music listening is about the experience. And if someone’s experience changes - be it through snake oil, rhino-horn or measurable improvements - for the better, who are you, we or anyone to tell them they are idiots for enjoying themselves.
I’m here because I love music. I love nice gear as well but it’s a tool for getting a better experience. As this is inherently subjective I buy what subjectively sounds ‘better’ to me. If you want to be as objective as possible that’s absolutely fine too. I hope everyone just enjoys their stuff and has fun in this hobby.
Atb
C
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Yup. “if it sounds good, it’s good”.
Still, there’s something special about knowing some dacs/amps/speakers/headphones are clean, neutral, and “measure” well. You know there’s not much of a difference between what you hear, and what was heard in the studio.
While I mostly agree, I think there is still a place for spreading truth to a lot of misinformation that gets around. Putting an argument out there for spending wisely where it counts is worthwhile (e.g. don’t blow half your budget on fancy cables), and if others still go for it then so be it. As you say, as long as they are happy.
The best advice I received was from my father over 30 years ago. “Any system is only going to sound as good as the weakest component.”.