Can digital audio playback be improved by resolutions greater than 16/44.1?

Apologies in advance if I don't respond to many other queries.

why have you not requested a retraction?
Short answer is that I do request corrections when anything I publish contains errors. But I wasn't the author of this, it was just a press release, 'important advantage' sounds to me like opinion rather than a factual claim, I can see how it could be used as a layman's phrasing of 'statistically significant', and scouring the internet would be impossible.


“I have [yet] to come across even one for hi res that does a decent job of doing level matched blind AB, leave alone a full protocol ABX… may I be pointed to even one ABX done in line with well established principle” – see the paper.
I have seen the paper. But is there any way to see a fully documented test itself? A link to one perhaps - that is the only way to it for most of us.
Unless I read the documented test, I can't conclude to how good it is. I may still not be able to do that, but it will be more than anything I have been able to find till now. By good, I mean how well single variable ABX protocols have been complied with.
Thank you in advance.

Most of the studies analysed in the paper were published by the Audio Engineering Society. They are all available from http://www.aes.org/e-lib/ , and can be downloaded freely by AES members.
One non-AES paper that can be downloaded by anyone is at https://www2.ia-engineers.org/iciae/index.php/icisip/icisip2013/paper/viewFile/160/146 . I don't by any means claim that this is the best, and it used an AB style paired comparison rather than ABX, but it should give you an idea of what a lot of the studies were like.

Apologies in advance if I don't respond to many other queries.
Short answer is that I do request corrections when anything I publish contains errors. But I wasn't the author of this, it was just a press release, 'important advantage' sounds to me like opinion rather than a factual claim, I can see how it could be used as a layman's phrasing of 'statistically significant', and scouring the internet would be impossible.


I'm sorry, but this is stretching the bounds of reality. No matter how many semantic arguments you wish to put forth, not even a layman would equate 'statistically significant' with 'important advantage'. I stand by my point; stating this study showed a 'important advantage' isn't justifiable marketing spin, or a translation to layman's terms; it is a flat out lie.

And If I were quoted as such when my results said nothing of the sort (in fact they say quite the opposite), I personally would request a retraction. I don't care it it was presented as an opinion, a fact, or an edict from God. I've seen no retraction, so I am left to think that you agree with the "layman's phrasing" which even to a layman, is a gross misrepresentation of the facts. This is pure marketing BS, and you seem to be a willing participant in that BS.

In short, it is astonishing that you would blame a mere misunderstanding, a marketing speak translation, or a dumbing down for laymen for what is in reality a lie, attributed directly to you. I'm left to wonder if AES's apparent support of all things Hi-Res has any bearing on your agreement with this "layman's phrasing".

It really is necessary to come as close to a 100% elimination of bias to have a dependable result... tester bias cannot be ruled out.
Good point and I fully agree.

I don't see that it is a double blind one.
Another hi-res evaluation paper by some of the same authors stated 'an operator was in a blind area outside the vehicle. It was not a double-blind experiment, but the subject and the operator could not communicate each other.'
I spoke with one of the authors for clarification on other aspects, and they used similar methodologies in both papers. So its likely only single blind, but with significant effort to reduce tester influence.

I haven't been able to get enough clarity on the outcome that approx 57% prefer HR to CD ah, that's the nature of these sorts of perceptual evaluation tests. They are actually well established throughout psychophysics (and applied to things like taste tests, perfume preference testing etc.), but its not your typical experimental and control groups as in evidence-based medicine. Think of the control as what would happen if participants were guessing. Then the outcome would be 50%. Note that a 50% result in a preference test with lots of trials does not necessarily imply that those participants can't discriminate, since it could be, for instance, that everyone can perceive the difference but half the participants prefer A and half preferred B. But a 100% result in those circumstances would be extremely unlikely to occur by chance.

For this experiment, standard error of the mean slightly overlapped 50%, so not considered significant. But it had a small number of participants and trials.

My understanding of human memory of sound quality is that it degrades in seconds and becomes unreliable - yes, and that would weaken any ability to discriminate. On the other hand, there is also the effect of auditory sensory memory. Studies suggest that it actually persists for quite some time. If the higher resolution content is played first, then one might retain the perception of that content if the lower resolution is played after (assuming that there's anything there to be perceived). And since we are looking at the limits of perception, long samples might be needed for listeners to identify differences. I grouped studies into those with short samples / quick changeovers vs long samples / long changeovers and the latter had much stronger results. But I wouldn't read too much into this since other differences between studies might have been the cause of this.


I haven't seen any test that adequately rules out bias and takes into account human auditory issues including memory duration, and proves a preference for HR. Even if people can hear a difference and even if that difference is due to higher quality, I doubt you'll find rigorous and general proof of preference. Such is the nature of subjective testing at the limits of perception and dealing with real world conditions. I'll give a couple of examples. In one study, participants were asked which audio format was best quality, and the live feed was the one most often ranked worst, suggesting that perhaps people didn't associate quality with purity. And a classic 1956 study suggested that those who have grown up listening to low quality reproductions may develop a preference for it.

if as you say a lot of the studies were like this, I am afraid that any meta analysis of these is just as flawed in its conclusions.
This is the big challenge with any meta-analysis, but luckily there is a lot of good advice from meta-analysis experts on how to deal with it. When I first started looking into this, it became clear that potential issues in the studies was a problem. One option would have been to just give up, but then I'd be adding no rigour to a discussion because I felt it wasn't rigourous enough. And its the same as not publishing because you don't get a significant result, only now on a meta scale. So I set some ground rules. I committed to publishing all results, regardless of outcome. I included all possible studies, even if I thought they were problematic (but discuss in detail potential biases). I decided that any choices regarding analysis or transformation of data would be made a priori, regardless of the result of that choice. And I did sensitivity analysis looking at alternative choices (like whether to exclude studies or analyse them differently).
One interesting thing that I found, which I did not at all expect, was that most of the potential biases would introduce false negatives. That is, most of the issues were things like not using high res stimuli, or having a filter in the playback chain that removed all high frequency content, or using test methodologies that made it difficult for people to answer correctly even when they heard differences.

Hi everyone, and @joshr thanks for joining us! This is a great discussion, and I'd just like to remind everyone to respect the rules of the community and withhold from personal attacks or letting the heat of the discussion make you forget that this is a welcoming place where everyone is entitled to their opinion. Let's keep it friendly!

Thanks!

... which made the effect of other factors like duration seem weak at best.

As for 2, you would clearly be comparing something very different if you look at commercial HD and CD quality recordings, if anything else was done in mastering besides just sample rate and bit depth conversion. But this argument works both ways of course. If the HD version is just an upsample of CD quality content, then its highly unlikely that there would be significant perceivable differences. Luckily, almost all studies avoided anything like this, and potential biases were noted and discussed when any such issues could have occurred.

If the HD version is just an upsample of CD quality content, then its highly unlikely that there would be significant perceivable differences. Luckily, almost all studies avoided anything like this, and potential biases were noted and discussed when any such issues could have occurred.
I agree that in the study I was able to read about, this issue isn't a factor; but in the real world HR audio is almost aways sold after remastering the recording used for the original CD. Because - I suggest - this is the only way for it to sound audibly different in the real world of normal homes and listening environments, to make people that already have the original CD, to buy it again. And so that those that do not, buy it at a higher price than the original CD that is still on sale.

I doubt that there is anyone successfully selling HR music closely allied to the kind you refer to - where both the HR and the CD are being sold at different prices, but are recorded at the same levels from the same master, and just down sampled for the CD version.

IMO and to my mind this has been a good discussion that has reinforced for me the philosophy that real world improvement in sound quality can be obtained - if required for the enjoyment of music - only via paying attention to who is doing the mastering and to speaker quality and placement/room acoustics/room response DSP. That is where there are real improvements to be found.

Of course, when the day comes that the good masterings are only available in HR format, it will be a different matter. But as of now there are no trends that indicate that this sorry state of affairs will come to pass!

Unable to navigate to page 3 of this thread. InSided, lol. Maybe this post will fix...

I simply have to say thank you to @joshr for joining in on this conversation! It is fantastic to have someone with your familiarity of this topic and depth of research connect with such a community!

As I'm sure you have noticed, many of the most active participants of this forum have built fairly strong views on this topic (and other topics :P) and as a result, may be perceived as being somewhat .... aggressive... in their response. 🙂 In my experience everyone on here does mean well and has a deep honest interest in the discussion, and you have added significantly to that conversation.

Incidentally, Having read much (with a lot yet to read) while I appreciate what people *may* be able to do in a testing environment, I stand by my original view that in a consumer market, higher resolution does not improve audio playback in any way that makes any meaningful difference to actual listening in a real world. I go back to the discussion referenced in the What Hi-Fi article : That people don't really note differences in their regular listening between mp3s and lossless such that they are not moving away from mp3s... I currently don't see the broader population demanding moving to higher-res as I don't perceive the typical individual truly discerning material differences in a real-world application. (And this is ignoring the potential communication bandwidth challenges that I perceive make product release/updates extremely problematic at this point in time.)

And training seemed to be such a strong variable that it appeared to override everything else. Essentially (and I'm being loose with the language here), every study where participants were carefully trained in the task showed a strong ability to discriminate, every study where participants were untrained did not.

The issue of training is very interesting. Years ago a friend and colleague proudly showed me the stereo he bought as an undergraduate at Harvard in the late 1960s. Despite their perished surrounds and yellowing paper cones, he loved the sound. Having just moved overseas, I bought a new stereo, including some excellent Canadian Mirage speakers. I took them around to his place to compare the sound, and he still preferred his speakers! I left the speakers with him for a week, and when I picked them up he had new B&W speakers. It took a while for his ears to make the decision.

So the question is, to train or not to train and stay in ignorance? Which brings greater happiness? I don't have a clear answer, but I tend to prefer knowledge over ignorance. And I know my friend now enjoys orchestral music more because he can hear and discriminate all the instruments more clearly.

I currently don't see the broader population demanding moving to higher-res as I don't perceive the typical individual truly discerning material differences in a real-world application.
Even if it could discern some differences, the broader population is far more interested in things like voice control, use of native apps, youtube video, home automation integration and the like. Even at the sacrifice of a little sound quality.

And who is to say it is wrong. For one thing, as the WHF interview says, stable streaming is more relevant to music enjoyment than marginal improvement in sound quality - music disruption can destroy the experience.

Secondly, the brain can effortlessly fill in for any little audible gaps that may exist - if they even do - between CD quality and Hi Res. But it cannot do so for things like voice control and all the other things that the broader population is now being offered. Sonos would be making a blunder if they did not take these trends and realities into account - and by all accounts, that is exactly what they are prioritising. They simply aren't interested in the market that cares less for these and more for hi res.

I still think it is a gimmick. But I haven't used it, and ten years ago, I may have said the same thing about Sonos. In fact, I stayed away from wireless/internet audio for few years because I thought the loss of sound quality would be unacceptable to my discerning tastes in music!

So I will reserve a final judgement on voice until it matures fully and I have had a chance to test it. I believe that your question of talking over the music - as one example - has been addressed to quite a degree via the mic tech in use, and it will only get better in the right direction in future.

Trueplay and even better versions of it are the future of sound quality improvements. But are you sure that it is Trueplay that is pulling of this trick - easy to determine by toggling it on/off. I suspect that the made for 5.1 master may be the one to assign most of the credit to.

And don't equate hi res with genuine mixed for surround sound audio. That isn't apples and oranges; surround sound mixes have a lot more audible content in the first place compared to 2 channel hi res. Somehow it never took off; perhaps because it can't be heard on the move?

Based on what you found till now then, it would appear that Sonos is focusing on just the right places for improving your listening experiences!