What is High Resolution Audio?
Posted by: Simon-in-Suffolk on 14 January 2016
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
joerand posted:J.N. posted:I accept that enjoying the sound of vinyl is illogical - it being fraught with the extant and inevitable technical compromises of the medium. Surface noise is never completely absent, so why do so many of us still enjoy it?
With vinyl there is literally physical contact in the replay chain between the music on the LP and the stylus. Humans crave physical contact - it's stimulating. There's no physical contact in digital replay.
Then there's the notion that humans inherently accept or expect imperfection in their everyday lives. The less flawed, more sterile listening environment of digital replay may create some subconscious discomfort - at least for those of us that grew up in the analog era.
While I accept and understand why people like Vinyl from a musical perspective. I would say the physical aspect has nothing to do with the whole replay. It might have to do something with getting you more into the music as you follow a certain ritual in mounting a LP, but that's about it....
I have also of course made the comparisons from a sound perspective and of course I recognize the differences, but that aspect is then purely musical.
Simon-in-Suffolk posted:tonym posted:The big problem in all this is the vast majority of people, even those with a great love of music, couldn't really give a damn about the quality of recordings because most have never picked up the deficiencies using the equipment they're most likely to own.
Really? I think we tend to think in our hifi bubble we are the only sub group that cares about audio quality - in my experience quality is important for many if not most - certainly with the younger generations - however what they consider a quality replay system may sound quite different from what many of us on this forum might consider. Question is who is right? I suspect both groups are.. after all recorded music and replay is a compromise and is subjective...
Absolutely. If your main listening session is a during a commute that includes a lot of backgrnd noise (the subway, traffic, etc.), you aren't going to lay down and accept something that is unlisteneable. But you're idea of high quality is largely going to be measured against the ability of the replay system to be heard over the top of all that. Bring that to the mastering level, and DR compression plays a large role. I've had people tell me that from their point of view everything audiophiles like is generally very low quality because you have to bend over backwards to create an environment to enjoy music in. To some extent the argument is true (even if the statement is BS). After all, a well mastered piece with great dynamic range variation is fairly unlistenable in a normal household with background sounds. Most of it is lost in the ether and the other half is deafening.
The fairly large market for not so cheap noise cancelling headphones and iPods supports this. But the downside is that we are at the mercy of marketing segmentation. We don't like to be pidgeonholed but we are. If people in marketing determine that the enough people who buy a certain album are likely to be contending with certain restrictive listening environments, then DR compression goes way up as a post mastering process. It is not wrong exactly but frustrating for anyone outside of that predicted segment who has more control over their listening environment.
Without a doubt, more can be done to make a recording "hi-res" by good mastering techniques than the format it is presented in - which is saying something because some formats sound consistently crap (mp3). I don't think there is a person on this forum who has not had a change in listening habits as a better system slowly shows up some almbums to be unlistenable on a decent system.
Simon-in-Suffolk posted:tonym posted:The big problem in all this is the vast majority of people, even those with a great love of music, couldn't really give a damn about the quality of recordings because most have never picked up the deficiencies using the equipment they're most likely to own.
Really? I think we tend to think in our hifi bubble we are the only sub group that cares about audio quality - in my experience quality is important for many if not most - certainly with the younger generations - however what they consider a quality replay system may sound quite different from what many of us on this forum might consider. Question is who is right? I suspect both groups are.. after all recorded music and replay is a compromise and is subjective...
In many cases for the younger generation, their view on what they consider "a quality replay system" is coloured by a lack of experience.
For instance, for his 16th birthday I gave my nephew a set of Sure 925s. He was amazed at what he'd been missing out on and that some stuff he previously thought was 'meh', was actually better than some stuff he thought great. He realized (with a 'z' as he's Canadian!) that his previous Apple phones simply weren't good enough to get a good assessment of a lot of tracks. He also (eventually) realised that uncompressed really does sound a lot better than AAC. This is also compounded in that quite a few young people have only really listened to electronically amplified music where the natural timbre of the instruments has, intentionally or unintentionally, been altered by the equipment used. Their lack of frequent exposure to natural acoustic music means that they don't have a stable reference point, and so more easily accept replay characteristics that are less than neutral. My nephew was lucky in that his sister was an exceptional music student, so he was exposed to good quality natural music.
Add to this that many select music to suit their limited systems, and when exposed to better systems they still do the same, but then the music they select then changes to match the new situation. As they regard this as the norm, they don't realist that their previous selection was based on artefacts.
To some extent there is subjectivity in the compromise in music replay, but there are are also objective targets such as a reasonable even and reasonably wide frequency response relative to human hearing capabilities. So taking headphones for instance, a bass boost starting at 250Hz reaching +10dB at 75Hz then falling 12dB / octave may sound subjectively impressive to some youngsters, but objectively it just isn't right. The problem here is that they get used to this and get to think that this distorted frequency response IS correct and unless they actually think about it in depth, they assume that better equipment is actually worse as it doesn't match their (distorted) expectations.
Huge posted:Add to this that many select music to suit their limited systems, and when exposed to better systems they still do the same, but then the music they select then changes to match the new situation. As they regard this as the norm, they don't realist that their previous selection was based on artefacts.
I would suggest that music lovers (maybe in contrast to hifi lovers?) select their music based on the message and attitude of the artist, rather than on the skills of the mastering.
In the end it is more important WHAT the artist tells and what his/her attitude is, them HOW it is told in terms of sound quality.
To quote Morrissey:
hang the blessed dj
because the music that they constantly play
it says nothing to me about my life
I have been listening to music daily for roughly 61 years and I have never heard anything I would describe as unlistenable. I have my personal preferences, but I can listen to and enjoy anything. I presume the artists are presenting their music the way they wish to present it. I listen on equipment I enjoy and am able to afford.
I certainly prefer somethings to others, but I can enjoy anything I listen to or new things I have gleaned from some contributor here. Some of my music gets played several times every year, some several times every week.
According to comments by members on this thread and frequently at other times on this forum, this acceptance of all music and sound quality would be presumed to be because my system would be inadequate to hear how poor something really is.
That kind of approach to music would pretty much tell me everything I would wish to know about any individual here. I enjoy the variety of choices and preferences, I steer clear of the dogma and posturing.
To quote Art Dudley:
"I wish you a satisfying and endlessly thrilling relationship with music. I
wish you the freedom to accomplish this by whatever means seem reasonable,
and even a few that don’t. I wish you enough money that you can buy what you
want at least a little of the time. I wish you enough flexibility so that
you’ll try something totally out of the ordinary from time to time, but not
so much that you’ll abandon the taste and judgment and sense of style that
drew you to your favorite music in the first place. And I presume you’ll
never look down your nose at the people who do things differently. Because
they are no less likely than you to get the same good results."
regards, Jeff A
I also don't think I posess any recording I'd regard as unplayable (OK, maybe a "Best of" The Commodores, now that is a stinker!). The worst for sound quality's a classical piece, Beethoven and Shubert. No dynamic range, lots of background noise, distorted. Cordot, Thibaud, Cassals. Recorded in 1926, and fabulous!
tonym posted:I also don't think I posess any recording I'd regard as unplayable (OK, maybe a "Best of" The Commodores, now that is a stinker!). The worst for sound quality's a classical piece, Beethoven and Shubert. No dynamic range, lots of background noise, distorted. Cordot, Thibaud, Cassals. Recorded in 1926, and fabulous!
Dear Tony,
That would yer Western Electric recording system at work, and yes the early system for recording 78s was not always very good in the earliest days. By 1932 EMI were using a very much better system developed in house by AD Blumlein.
But the performances you mention are still priceless and should not be missed!
ATB from George
Dear George,
IIRC, back in the distant mists of time, it was your recommendation!
Best wishes,
Tony.
Dear Tony,
I spend my efforts in sharing my enthusiasms, and I can only say that it is a great pleasure for me when someone shows that they have enjoyed sharing my enthusiasm. I take some strength from the thought that I am not “always” wrong!
Best wishes from George
Edwin Fischer playing Schubert in 1938 in Abbey Road with Blumlein’s now more or less fully developed moving coil micriphone and moving coil cutting head ...
However, the real point is that this is Schubert in sublime style!
I’d call this “hidef” by any standard even on youtube MP3, and so fine as to be more or less incredible for quality ...
Sometimes a great performance is met with an equally great recording, ... even seven or eight decades on.
https://www.youtube.com/watch?v=EgB4HHuW4JI
Best wishes from George
Impromptus available on Testament CD. Get it! There are seven others, played just as transcendentally ...
Jeff Anderson posted:.According to comments by members on this thread and frequently at other times on this forum, this acceptance of all music and sound quality would be presumed to be because my system would be inadequate to hear how poor something really is
That kind of approach to music would pretty much tell me everything I would wish to know about any individual here.
That's a pretty short yardstick to judge people against.I love music and the better my system the wider my appreciation gets. However, I'm easily distracted, so when things sound 'off' I have a real hard time hearing music and start hearing sounds instead. I think this varies from person to person but I absolutely do not feel less of a music lover simply because I cannot enjoy music below a certain quality threshold. For me the devil is in the details. I don't want to just hear the artist's message and catch the tune. I want to be wrapped in a performance.
And for me, the most distracting of all things is when DR compression is taken a step too far. It can kill my enjoyment of any piece of music to the degree I'd rather have silence. So I definately hit upon the odd album mixed with a very different audience/playback system in mind that is, to me (a music lover) unlistenable.
I don't think there is anything wrong with being discerning, picky, choosy, hard to please, anal (choose whatever you find appropriate). After all, we generally don't think all movies or worth our time; nor all foods worth eating; nor all wines equally worthy. I think it is good to set a quality bar for all things you repeatedly expose youself too. Life is too short not to.
And I'm perfectly happy with what that attitude says about me.
p. posted:.I would suggest that music lovers (maybe in contrast to hifi lovers?) select their music based on the message and attitude of the artist, rather than on the skills of the mastering.
But there are also who like both - especially those that create and produce contemporary music. I was talking to a very dear friend of mine yesterday who is a composer, engineer, and has been an occasional recording engineer. He is also well connected with a few producers still active in the business.. he was illustrating to me how the master engineer can work with the artist(s) to convey the emotions and feel that is required, and was playing me examples of this - it was great
We listened to some fantastically well recorded and mastered albums and compared with more recent remasterings - and the differences were interesting not least because of the better quality ADCs and DACs more recently used. He also showed me using his knowledge of various producers, recording techniques/equipment at the time how, in the mid 80s many recordings became flat and the rise of the bright/edgey master for prominence, and also the influence of Trevor Horn on the industry at that time - it was fascinating listening to changing mastering styles - both through fashion and technology. It was a fascinating evening.
I think sometimes we forget the skill and thought that can go into this area of music production.
Having said that Kate Nash's album "Made of Bricks" took the award yesterday out of the albums we listened to for the most appalling mastered album. Flat, overly compressed and horribly clipped and distorted.
Simon
Simon-in-Suffolk posted:p. posted:.I would suggest that music lovers (maybe in contrast to hifi lovers?) select their music based on the message and attitude of the artist, rather than on the skills of the mastering.
But there are also who like both - especially those that create and produce contemporary music. I was talking to a very dear friend of mine yesterday who is a composer, engineer, and has been an occasional recording engineer. He is also well connected with a few producers still active in the business.. he was illustrating to me how the master engineer can work with the artist(s) to convey the emotions and feel that is required, and was playing me examples of this - it was great
We listened to some fantastically well recorded and mastered albums and compared with more recent remasterings - and the differences were interesting not least because of the better quality ADCs and DACs more recently used. He also showed me using his knowledge of various producers, recording techniques/equipment at the time how, in the mid 80s many recordings became flat and the rise of the bright/edgey master for prominence, and also the influence of Trevor Horn on the industry at that time - it was fascinating listening to changing mastering styles - both through fashion and technology. It was a fascinating evening.
I think sometimes we forget the skill and thought that can go into this area of music production.
Having said that Kate Nash's album "Made of Bricks" took the award yesterday out of the albums we listened to for the most appalling mastered album. Flat, overly compressed and horribly clipped and distorted.
Simon
Sounds a very interesting discussion.
I have often (rightly or wrongly) blamed Sony's ProTools for a lot of the sameness in some modern "popular " recordings (quite apart from obvious brickwalling). Did the ubiquity of ProTools come up in your conversation at all?
SJB
feeling_zen posted:That's a pretty short yardstick to judge people against.I love music and the better my system the wider my appreciation gets. However, I'm easily distracted, so when things sound 'off' I have a real hard time hearing music and start hearing sounds instead. I think this varies from person to person but I absolutely do not feel less of a music lover simply because I cannot enjoy music below a certain quality threshold. For me the devil is in the details. I don't want to just hear the artist's message and catch the tune. I want to be wrapped in a performance.
And for me, the most distracting of all things is when DR compression is taken a step too far. It can kill my enjoyment of any piece of music to the degree I'd rather have silence. So I definately hit upon the odd album mixed with a very different audience/playback system in mind that is, to me (a music lover) unlistenable.
I don't think there is anything wrong with being discerning, picky, choosy, hard to please, anal (choose whatever you find appropriate). After all, we generally don't think all movies or worth our time; nor all foods worth eating; nor all wines equally worthy. I think it is good to set a quality bar for all things you repeatedly expose youself too. Life is too short not to.
And I'm perfectly happy with what that attitude says about me.
Hi FZ,
Unfortunately, you missed my point completely, or I attempted to make my point poorly.
And I agree that if something distracts from your enjoyment it is reasonable to consider listening to it less or perhaps not at all. That is a choice. But that, to me, is not the same as declaring something as "unlistenable" because of technology concerns or level of equipment used, as others on this thread and other threads have proclaimed.
Far too many things here are posted as "absolutes". That is wholly different than preferences and opinions and choices. And please don't interpret my original comment as an "absolute" other than because of my inability to make my point properly. I see that as different than endless posts about single view agendas. Perhaps I am wrong in how I represent myself. I, too, will bear that responsibility.
As far as drinking wine, watching movies, and eating food, your quality choices are your own. But they don't make french fries inedible, MD20-20 undrinkable, Pee Wee Herman unwatchable, or MP3s unlistenable. I know there is at least one individual here who, because of a physical condition, is unable to listen to the artifacts of MP3 (or lossy audio). I don't ever remember him presenting that as lossy is unlistenable, but something he is unable to be exposed to and have any enjoyment (and avoid actual physical distress). That is a subtle difference, but for me it speaks volumes about the individual person and his posts.
I wouldn't choose to use the word attitude, but I expect I will be judged, as well, for my posts on this forum. If you wish to dissect my original post, focus on the Art Dudley quote. Not because he is god, but because he is reasonable. I hope I am too.
Enjoy your music, Jeff A
Sloop John B posted:Sounds a very interesting discussion.
I have often (rightly or wrongly) blamed Sony's ProTools for a lot of the sameness in some modern "popular " recordings (quite apart from obvious brickwalling). Did the ubiquity of ProTools come up in your conversation at all?
Yes it did! - ProTools running on Macs in particular. My buddy felt it was being used less now than in the past - but didn't offer what its being replaced by.
Simon
Simon-in-Suffolk posted:p. posted:.I would suggest that music lovers (maybe in contrast to hifi lovers?) select their music based on the message and attitude of the artist, rather than on the skills of the mastering.
But there are also who like both - especially those that create and produce contemporary music. I was talking to a very dear friend of mine yesterday who is a composer, engineer, and has been an occasional recording engineer. He is also well connected with a few producers still active in the business.. he was illustrating to me how the master engineer can work with the artist(s) to convey the emotions and feel that is required, and was playing me examples of this - it was great
We listened to some fantastically well recorded and mastered albums and compared with more recent remasterings - and the differences were interesting not least because of the better quality ADCs and DACs more recently used. He also showed me using his knowledge of various producers, recording techniques/equipment at the time how, in the mid 80s many recordings became flat and the rise of the bright/edgey master for prominence, and also the influence of Trevor Horn on the industry at that time - it was fascinating listening to changing mastering styles - both through fashion and technology. It was a fascinating evening.
I think sometimes we forget the skill and thought that can go into this area of music production.
Having said that Kate Nash's album "Made of Bricks" took the award yesterday out of the albums we listened to for the most appalling mastered album. Flat, overly compressed and horribly clipped and distorted.
Simon
Agree, my intention was not to underestimate the importance of an engineer / producer in the creative process and the quality of the music.
My point is that boring and uninspired music (my subjective view of course) can not become exciting for me just by a perfect production process.
On the other side I assume it is the final touch of a good producer that makes great music outstanding.
"I would suggest that music lovers (maybe in contrast to hifi lovers?) select their music based on the message and attitude of the artist, rather than on the skills of the mastering." Yes, and no. I was listening to Rainbows Rising last week. Its a great album that I loved when I was young and that I first encountered on rubbish playback hardware. The message and music is still great but the quality of production on the CD is dreadful and it was hard to listen to with the same enjoyment I used to derive from it. My fave group, Rush, have always hit the spot for me in terms of their message and artistry but their CDs have been variable in terms of sound quality - I still listen to them but some less than others although the 24 bit offerings have helped. If I see a painting by a great artist I will enjoy it more if it is applied to a good canvas and using good, durable paints. The same applies with music, a great message and wonderful musicianship can be diluted by a poor recording/medium imo
Just for fun (and a little curiosity), I listened to Kate Nash "Made Of Bricks" and Rainbow "Rising". Didn't like Kate's lyrical content enough to dig too deep into her catalogue, the instrumentals were decent enough. It was nice to revisit Rainbow "Rising", an album and genre I spent a lot of time with back in my younger and vinyl days. I can see going there again once in a while. I guess I don't hear sound. I am okay with that. Good listening, Jeff A
I thought I'd share some research papers from the AES Open Access series - which means anyone should be able to read.
This paper is fascinating and looks about the science behind quality listening tests/auditions on various audio replay hifi / equipment...
http://www.aes.org/tmpFiles/elib/20160221/18105.pdf
and this article - which is perhaps more relevant for the views on varying mastering quality - some analysis undertaken on how people perceive mastering style and quality for popular music
http://www.aes.org/tmpFiles/JA...AES_V64_1_2_PG23.pdf
Simon
Unfortunately, Simon's links above are dead on my PC. Bet I'd have found them interesting.
Based on the premise that hi-res quality is all over the board these days and folks don't really know what they're buying into, I'd offer these recent findings on an old classic rock album ....
| Artist | Album | Year | DR | DR min | DR max | Codec | Source |
|---|---|---|---|---|---|---|---|
| Aerosmith | Greatest Hits i | 1980 | 12 | 11 | 13 | lossless | Unknown |
| Aerosmith | Aerosmith's Greatest Hits i | 1980 | 12 | 11 | 13 | lossless | Unknown |
| Aerosmith | Aerosmith's Greatest Hits [vinyl] i | 1985 | 12 | 11 | 13 | lossless | Unknown |
| Aerosmith | Greatest Hits i | 1986 | 12 | 11 | 13 | lossless | CD |
| Aerosmith | Greatest Hits i | 1986 | 14 | 12 | 16 | lossless | CD |
| Aerosmith | Greatest Hits | 1989 | 12 | 11 | 13 | lossless | CD |
| Aerosmith | Greatest Hits [Acoustic Sounds 24/96] | 2014 | 08 | 07 | 08 | lossless | Download |
Not a good showing for the 24/96 album at least based on the singular, debatable metric of dynamic range. Who knows what this matrix is worth without having heard the hi-res versus the older versions? And it's just one album.
Maybe, as Simon suggests, mastering style and quality on the hi-res can trump absolute DR? Would be nice to get live links to the AES papers.