I was reading a thought provoking article by Bob Stuat at the AES on what constitutes high resolution audio. Here is my summary of his article.
Firstly he makes a good comment, that in hi res audio we tend to borrow many metaphors and adjectives from the visual world such as focus, transparency and definition, where he maintains hires audio should be natural, resembling real life, and sounds should have clear depth and positioning and seperate readily into perceptual streams, particularly where environmental effects cause multiple arrivals to our ears providing temporal resolution of sound structures which is akin to spatial resolution in vision. I agree with this observation..
Stuart then goes onto define high res audio without falling into the traps of limiting to the narrow definitions of digital audio Nyquist sample frequency and bit depths.. So in the analogue world, assuming high definition equates to natural sounding, then referring to the research by JW Oppenheimer and others that hearing is not bound by pitch perception (approx 18kHz) but our brains appear to exploit population coding, and can approach a temporal resolution of 8 υS. This implies a Gaussian bandwidth of about 44kHz .
Next Stuart introduces encoding and replay systems ... Still all in analogue. He suggests that in a typical recording and replay environment it could be appropriate to consider 8 cascade stages .. Now each stage impacts the bandwidth on the other, so with 8 cascaded interfaces so as to protect the bandwidth of 44 kHz through the cascade, each stage should more likely have a bandwidth of 100 kHz.
Now any of these of stages could be digital and then Nyquist and bit depths comes in to play .. So here we can see at least 96kHz and upto 200 kHz (192kHz) given the cascaded bandwidth issues to fully capture 8uS spatial awareness. But referencing papers by M.S. Lewicki, and Jackson, Capp and Stuart, he states evidence shows with current digital sampling technology and hardware through decimation and interpolation that the results above 96kHz sample rate are very much diminished and that 96kHz would preserve most of the spectral content.
Now Stuart talks about bit depth of sampled audio. The increased bit depth above 16 bit give diminishing returns, and P.B. Fellgett's research into the thermal noise limit of a microphone shows that the fundamental limit of a microphone can be bound by a 17.5bit 192 kHz LPCM channel, therefore there is often little justification for using more than 18 bits.
Therefore to summarise Stuat effectively suggests that Hi Res audio should capture as close as possible the 8uS temporal resolution and offer at least 18 bit LPCM dynamic range. (So with digital audio at least 96kHz sample rate with 18 bit sample length - or more likely the excessive 24 bit)
Stuart then talks about air temperature, air flow and shape of recording and listening rooms, as these will modify the audio .. But that's another story.
So food for thought, and nice to have a view that is more from a science/engineering perspective rather than the marketing room. I recommend this paper to AES members on this forum rather than rely on my paraphrasing 
.. J. Audio Eng Soc Vol 63 No 10 2015 Oct.
Simon
Posted on: 15 January 2016 by Adam Zielinski
You will find that the better the components, the more revealing they become.
Badly produced / masterd albums will sound bad. Well produced albums will sound magnificent.
One must remember that a typical, popular album is mastered to sound OK on cheap stereos, in cars and bars.
Posted on: 15 January 2016 by Innocent Bystander
Seems the focus should be on seeking well-mastered music, resolution notwithstanding.
Turning that around, the focus should be on getting the music industry to produce well-mastered music... I seek music I like, my taste taking precedence over any consideration of mastering - and where, as is often the case, it is only available digitally in one mastered form I have no option but that even if it's less than perfect.
It's different where there may be more than one mastering available, though the challenge then is how to know which is better without buying all, and that can multiply the cost of music considerably. When approaching something new to me, where there are options I have tended to go for the highest resolution available, in the expectation that it should be the best sounding one - but clearly that is not necessarily the case, which is a far from satisfactory situation.
Posted on: 15 January 2016 by Allante93
Seems the focus should be on seeking well-mastered music, resolution notwithstanding. Properly done Redbook does the trick...
Absolutely agree
Yes, that''s the point I was trying to make with Diana Krall, Love Scenes. I just parted with my LP 12 last year, hated to see her leave, but she wasen't getting much playing time, out 300 albums, Maybe 20 good recordings.
Same problem with CDs, find my self playing the same 20 CDs. I agree with Adam "Badly produced / masterd albums will sound bad. Well produced albums will sound magnificent."" I guess if its done properly in Studio, it will sound well on one's System, be it CD's or Records!
I do find, that Stockfisch, does a fine job with CDs.
The Armchair QB!
Posted on: 15 January 2016 by Allante93
...
Where I'm a bit confussed, Hi Res Récords, CDs, and Streaming, when Adam confessed to three formats with récords. Made me think, I have four formats with CDs, HDCD, Xrcd, Xrcd2, Xrcd24.
Xrcd, Xrcd2, Xrcd24 are not CD formats. They are just plain 44.1/16 CD's. It is just the mastering technology that has been done differently.
The end result is just an ordinary RedBook CD.
HDCD is also ordinary RedBook CD (even with some loss compared to non-HDCD, but that is supposed to be unhearable), UNLESS you have a CD-player that is capable of decoding HDCD, only then you will gain 4 extra bits and get a 44.1/20 signal.
My friend and I split a $200 order from exclusive Disk. Compared two versions of Dianna Krall, Miles Davis, and something else, can't recall at the moment, but the end result, not much difference, if any!
For understanding, Please correct me if I'm wrong, playing out of an CD 555, be it Xrcd, Xrcd2, Xrcd24, or Patricia Barbra Hdcd, it will still be Standard 16 bit Redbook!
Even when a little light displays Hdcd on my Cdx2, it will still be Standard 16 /44Hz Redbook, Correct?
Hence, The Article, 24/192 Music Downloads, Don't make sense!
By Stuart.
Hi Resolution Downloads, as it pertains to Naim's Reference NDS/Streamers, not TTs and CDPs!
The Armchair QB!!!
Posted on: 15 January 2016 by Essad Ribic
hdcd will be 20 bit,the rest 16 bit,xrcds and such are mastered on a different equipment,but cd-s are still 16/44.If they sound better,it's because better studio mastering and glass master manufacture in cd print factory(i believe they tightly control all of this).
hdcd is 20 bit only on player with hdcd decoder chip(555 and cdx2 ARE hdcd players),if player doesn't have that decoder,it's down to regular cd res.
Posted on: 15 January 2016 by Sloop John B
Strange I seem to remember a post by Julian saying Naim albums were not released as HDCD as it made no difference to the sound. The only reason Naim CDPs were HDCD was DAC they wanted to use just happened to be a HDCD one.
I know a brickwalled Hi Res file will sound dramatically worse than a CD version with dynamic range. I've yet to be convinced that a well mastered hires file sounds much more that subtly better than the same CD version.
Then again, my hearing is diminishing and this may be the reason that I just don't "get" hires
SJB
Posted on: 15 January 2016 by joerand
A look at the DR database corroborates your point Simon. Decoded HDCDs score slightly higher than the same disc not decoded. Still, decoded HDCDs of a given album typically score lower DRs than earlier CDs from the 1980s or than the original vinyl.
As for the more general hi-res discussion it seems a shame that buyers often don't really know what they are paying for; upscaled redbook or true dedicated remasters. "Sourced from the original analog tapes" is a term often bandied about for remasters from the classic rock era. Well, what else could it be since the original recording was sourced to tape? That term doesn't mean the original tapes were directly used for the remaster. Some tapes are no longer in suitable condition (and then there's the Steely Dan debacle).
Anyhow, I get the sense vinyl users are content to realize the limitations of the medium and enjoy it for what it is. Original pressings are likely not topped. Digital technology offers continuous potential betterments and with it the hope for audiophiles that there is something better to be had. From what I read here, some hi-res is better, but a lot has folks frustrated with what they paid for.
Well recorded/engineered/mastered albums seem to shine on their own merits, regardless of format. It even comes through at the MP3 level. If not done well from the onset then its just the lipstick on a pig analogy, and it becomes more glaring with better gear. I entered the Naim game four years ago with my sights set on a Unity and streaming. After a lot of homework and forum reading I came to the conclusion that I'd best remain a dinosaur and stick with physical media. I've never regretted my choice and don't think I'll ever change. I can live with my current music library even if I never add another album. Streaming has much upside; great for those that enjoy it, but I'm happy not to be a part of that arms race.
Posted on: 11 February 2016 by Simon-in-Suffolk
Thought I'd share:
I was listening to some Ella Fitzgerald 192/24 tape transfers this evening.... and once I got used to the presentation, and shut my eyes, the audio became mostly transparent to any ambient sound in the house.. It was a strange experience and totally captivating... The music was all there.. But there was like a layer of processing that I had removed from my brain to listen to the music.. It genuinely was fascinating...
i then later put on a fine 44.1/16 recording of Django a la Craole by Evan Christopher... a renown live recording.. But by comparison it initially sounded shut it and synthetic... However after a while it seemed to significantly improve as my brain adjusted.. but it's sound was always different from the ambient house sounds...albeit the musical message was there from the start.
Perhaps a fascinating insight into Hidef and how my brain hears sound....? and perhaps a demonstration that the advantage of hidef is low level timing queues rather than tonal frequency bandwidth . I love this hobby.......
Simon
Posted on: 12 February 2016 by Huge
In all cases I will take a good rendition of a piece on Red Book over a less well played rendition in high res.
Once a basic level of recording technology and competence has been employed, then the artistic performance is far more important that the technology.
The same principle applies to sound engineering and mastering (/ re-mastering), if not done well they can destroy the meaning of the performance, and no recording or distribution technology can rescue that.
Posted on: 12 February 2016 by Huge
I would also add another criticism of the xiph.org piece. ALL his tests were done with steady state sine waves. These are the easiest type of signal for equipment to process as it's an electrical analogue of simple harmonic motion (and indeed become such at the loudspeaker!).
Real music isn't so simple and just looking at sine waves completely ignores transient behaviour of the system, including important things like TID and the effect of noise shaping on low level transient information in the signal. For instance, his 1/4 bit 1kHz sine wave can only be extracted from the noise and dither because it's a steady state periodic signal. This missing analysis introduces a significant number of areas of doubt into his conclusions - areas he has completely failed to address.
Posted on: 12 February 2016 by Harty601
In all cases I will take a good rendition of a piece on Red Book over a less well played rendition in high res.
Once a basic level of recording technology and competence has been employed, then the artistic performance is far more important that the technology.
The same principle applies to sound engineering and mastering (/ re-mastering), if not done well they can destroy the meaning of the performance, and no recording or distribution technology can rescue that.
I agree - I have heard some truly awful Hi Res versions of favourite albums - in the same way as I have encountered the same on CD over the years (and Vinyl for that matter).
But when it is done right, on my system and to my cloth ears, Hi Res blows Red Book and Vinyl away.
I also agree that the music itself, and performance there of, is everything. I have some fantastic sounding Hi Res files (in terms of SQ) that are the musical equivalent of self manipulation!! Or soulless performances devoid of passion. No open sound stage / inky blackness / space around performers, or any other terms we try to come up with to explain why we spend our money can make up for that!
Posted on: 12 February 2016 by Darke Bear
Many CDs I have that were mastered between 1980-2000 sound incredible. As I have continued to improve my system I find revelation of more dynamic range, information and musical timing information that keeps appearing from these CDs.
Now after 2000 things seem to gradually get worse and worse. The noise floor is a shadow of what was achieved on these early disks and I suspect the equipment being used to master them has a lot more to do with it than usually suspected. Even leaving aside the pervasive and ubiquitous use of 'a bit of compression to make it sound better', I believe that the music mastered on modern computer-based systems can have a lot higher noise floor that that achieved with the earlier mastering equipment.
For example, take Pink Floyd albums 'Division Bell' and 'Lapse of Reason' and the latter earlier album has vastly better SQ and greater dynamic range than the later one. I like the music on Division Bell, but it is very so-so SQ recording, not the worst about but a big fall from 'Lapse of Reason'.
To get a good rendition of the track High Hopes' I use the live album, which seems to not have suffered the same poor mastering and actually sounds more dynamic than the studio album by a very long way.
Then some of the Mystery of 'what are they doing' came from a throw-away comment by Dave Gilmour that he just takes sound captures from his tablet and adds it to the mix! That will set a noise floor - crazy, but who cares as nobody is going to play it on a HiFi.
...all the above leaves aside the discussion of so-called High Definition - as what I've just said rides a cart and horses and their poop right through what might otherwise be possible.
So I continue to buy CDs from a time when more care was taken. I hope things will improve someday - then when I hear a so-called High Definition track I may go 'wow!' and finally move on from my CD Player.
DB.
Posted on: 12 February 2016 by George F
With classical music the situation has parallels. Some of the very earliest CDs are still superb, and some remasterings have less than stellar quality, but about 1993 EMI set about an approach which has a great deal to commend it for their classic remastering of analogue recording from tape and 78 metal master parts.
They used the higher resolution of 24 bit with 96 K sampling for the initial transfers, and this was subsequently the basis of a Red Book standard master. They had specially made equipment installed for this process, and subsequent CD re-issues of analogue recordings really showed the highest imaginable production standards and quality.
These restorations are still frequently made the basis of subsequent re-issues, and I doubt that much more could be achieved with the old recordings.
I think that new recordings of classical music are astonishingly good. In recent times many companies have moved back to the simpler microphone set-up, resulting in coherent sounding recordings that work well in stereo or mono.
But I do understand from a certain amount of experience of friends who bring popular music recordings here to have a listen on a highly resolving system that in the popular field, new recordings and re-issues are frequently worse than older CD re-issues and first releases of previous decades. Really that is deplorable, but nowadays most popular music is actually designed for iThingies, and the workplace or car radios.
The quality of pop music recordings reflects the market for pop music, and it is hardly a consideration at all, how these recordings do sound on very fine replay.
There is nothing to indicate that this situation is going to change.
ATB from George
Posted on: 12 February 2016 by Allante93
Posted by DB:
""So I continue to buy CDs from a time when more care was taken. I hope things will improve someday - then when I hear a so-called High Definition track I may go 'wow!' and finally move on from my CD Player.
DB.""
Just Curious DB, are you familiar, with Stockfish, and XRCD2 and XRCD24!
I also I'm quite fond of The DMM/SACD Stockfisch. But can only find the one DMM!
Sold my LP 12, needed the funds for my Naim Quest, but it was more of a status thing. Never really played it, and didn't want to invest 8K to bring it up to date.
But I own about 300 CD's, and find myself listening to the same 30 or so, about ten% or so. but only 5% is Top Choice.
Trying to go active, Cdx2>282>HCDR>3 x 250.2>Briks, but in the meantime Would I get more enjoyment out of my CD's with an 2nd hand 555PS on the Cdx2?
The Armchair QB!
Posted on: 13 February 2016 by Darke Bear
I had not explored any esoteric disks much, as I've experienced disappointment with some so-called expert re-mastering disks which I didn't like.
What I do find is that the same issue of a CD is in fact totally different depending on what pressing plant issued it in many cases. Crazy, but I have purchased several CDs of apparently the same identical album, issued the same year and get all sorts of results - with EQ being applied to some to boost HF or remove low bass - yet the disks look identical apart from country of manufacture and some serial numbers pressed onto the disk - and sometimes even identical serial code marked disks are totally different in SQ.
For one of my favorite Albums of an Artist I like I purchased seven disks second-hand from various sources and of these four were similar but all a bit different, two were very different (one from Japan was very clear but seemed too overdone) and one was the 'find' - stonking SQ with full clean dynamic range and subterranean bass which made the others all sound poor, yet they were all supposed to be the same!
This last disk was, I think, a clean transfer whilst the others all had been adjusted.
It does make me wonder what versions people are really listening to sometimes.
All this before we get to consider High Resolution - of what is the question?
DB.
Posted on: 13 February 2016 by Innocent Bystander
I experienced similar - though only with one album and two copies! I was astounded at how different, the only evident difference from the packaging being that one was pressed in Germany and the other UK. That was when I first realised how meaningless comparisons are between different media, such as vinyl and CD.
And I, too, have been less than enamoured with some modern re-mastering efforts, not even thinking of the SQ, but the engineer simply has meddled with the mix compared to the original version I liked. To me, remastering would be best keeping as close to the original mix as possible, but correcting such things as curtailed frequency response where appropriate, and reducing (ideally removing) compression where, for example, that may have been done because the target medium was vinyl. The only reason ever to alter the mix itself, to my mind anyway, would be if the artists themselves hadn't been happy with it at the time and had perhaps bowed to pressure from the record company - but to fix that needs the original artists, not some ellegedly whizzo re-masterer. Any other variations in mix should be released as under a different name, e.g XXX's remix of YYYY, or if done by the original artists, YYYY interpreted for 2015.
Hi def should then be getting whatever mix is available to the listener exactly as it is in the mastering room, and any remastering would be good if it aimed to minimise SQ losses from the master recording.
For me, the jury is out regarding higher resolutions than red book: there are clearly too many variables to allow a listener to attribute a bett sound specifically to the resolution - however, it seems to make sense that if recorded at a higher resolution then distributimg at listeners at the same resolution is likely to be best, if only because it will go through less overall processing and thus any errors/artefacts will be minimised. Meanwhile the sensitivity of the human ear/brain combination, combined with reception of sound through pathways other than the ears, is such that I can believe that more information might be receivable in our heads with resolutions higher than red book, despite the very clear arguments behind the RB standard: so it might well be that higher definitions asvailable as the transport medium could result in improved perceived SQ, even if it is only a nebulous feeling while listening, rather than anything you can put your finger on.
As for the revelation about David Gilmout's apparent lack of concern for SQ, I'm shocked because Pink Floyd were one of the main forces behind trying to improve SQ back in the 70s and 80s.
Posted on: 13 February 2016 by Allante93
........And I, too, have been less than enamoured with some modern re-mastering efforts, not even thinking of the SQ, but the engineer simply has meddled with the mix compared to the original version I liked. To me, remastering would be best keeping as close to the original mix as possible, but correcting such things as curtailed frequency response where appropriate, and reducing (ideally removing) compression where, for example, that may have been done because the target medium was vinyl.........
I get what you are saying, an audiophile friend was gracious enough to split the cost and we A-B'ed some well knowed classic recordings, including Miles Davis!
In short the difference was minimal, to say the least, for better or worst.
However, when Extended Resolution CD (XRCD) Technologies are applied to contempary recordings, where Artist are not taking short cuts, and Record labels, like Stockfisch, pay close attention to details, the results is an improvement over the norm.
If the Music is to your liking, give it a spin!
XRCD2: Jacintha, lush life, 2001
XRCD24/Stockfisch: sara k, HELL OR HIGH WATER 2006
The Stockfisch DMM-CD/SACD Vol.1 2013
Allante93!
Enjoy your Music!
Posted on: 14 February 2016 by Simon-in-Suffolk
Nah John, vinyl is light years from Hidefinition in its true sense.. i.e. matching reality. Vinyl is about sounding pleasing and attractive.
True hi definition audio is really more about virtual reality and less about music.
I would argue the point that musically speaking I feel hidef could be largely irrelevant.
But of course we shouldn't get hung up thinking hidef is associated with 'Sample rate'. That really is a very simplistic proxy that in my experience fails to match true hi definition. Hidef is about accuracy - not how the sound is reproduced, encoded, or conveyed.
I can't help feeling for many people so called 'hidef' is simply a euphemism for recording and mastering quality.
Simon
