Originally Posted by arnyk
Interestingly enough this paper is neither an AES conference paper or a JAES article." At least I can't find it published that way. It appears to be a rewrite of a 1988 (24 year old!) article in the now-long-departed Audio magazine. It's a corporate white paper that has no standing as an industry standard or recommendation.
The online version of the paper is a revised an updated version of what was presented at AES Conference: http://www.aes.org/e-lib/browse.cfm?elib=7140
[ from 1997 not 1988]"Coding Methods for High Resolution Recording Systems
This paper reviews the recording and reproduction chain from the viewpoints of digital audio engineering and psychoacoustics. It also attempts to define the audio requirements of a transparent digital audio channel. The theory and practice of selecting high sample rates such as 96kHz and word lengths of up to 24 bits are examined. The relative importance of sampling rate and word size at various points in the recording, mastering, transmission, and replay chain is discussed. The paper then examines types of coding that are capable of attaining the target performance, describing the advantages of schemes such as lossless coding, near-lossless coding, and matched noise shaping with pre-emphasis.
Author: Stuart, J. Robert
Affiliation: Meridian Audio Ltd., Stukeley Meadows, Huntingdon, UK"
In contrast, we are discussing an online article by Xiph that has none of credentials you require and has its own built-in biases.
This paper is arguably part of the support for SACD and DVD-A which are now known to be failed technical initiatives that failed to make it in the mainstream consumer marketplace.
Bob Stuart company's solution for lossless compression, MLP, was selected as the mandatory lossless audio compression for that for DVD audio and eventually (optionally) in Blu-ray in the form of Dolby TrueHD. As such, Bob had little love for SACD. If you read the report, or even if you don't and go by the conclusion of what I post, no one who is a die-hard DVD-A fanboi would say that anything above 14-bits dithered and 58 KHz is a wasted of bandwidth. So no, your characterization is almost the opposite of the spirit of the paper.
Bob's position is that of a moderate here that simply says CD is just a bit too low of a spec and he goes on for a whopping 38 pages
making his case, far, far more detail than the article being discussed in this thread.
FYI, I usually cite this paper when someone demands to highest sampling rate, bit depth, not the other way around. It makes for very poor evidence in support of the formats you mention due the conclusions it reaches, especially regarding bit depth.
The paper in question is full of unsupported assertions.
As is your statement Arny
. The paper has 27 references (none of the forum arguments as cited in Xiph article). It has ~17 pages of graphs, simulations and diagrams to back what it describes. You read two reports that more or less agree with each other yet opt to back the one with smaller numbers better. I call that prejudice
Managing those prejudices is a well-known and widely-practiced art (among professionals, particularly those doing R&D) which the paper in question thoroughly ignores.
The paper is a scientific look at the issues. You make it sound like he listened to two tracks and declared high resolution audio the way to go. Look at statements like this from Bob:"Although there is a small lobby that suggests even higher sample rates should be used – like 192kHz– the author disputes this; preferring to point out that when 96kHz channels have been correctly designed in terms of transmission, filtering, etc, that higher rates simply will not offer any benefit.
I realise that by expressing the requirement of transparent audio transmission – I am nailing a flag to the mast and lay myself open to all kinds of attack! However, this analysis has been based on the best understanding to date on this question and we should exceed this requirement only when there is no detrimental cost to doing so."
So as you see and I noted before, his stance is against "biggest numbers are better" and agrees far more with the Xiph article than disagrees.
"There is very little hard evidence to suggest that it is important to reproduce sounds above 25kHz. Instead there tends to be a general impression that a wider bandwidth can give rise to fewer in-band problems."
The above is a mixture of technical truth and opinon stated as fact (OSAF).
As I noted regarding bias, the rest of us also express opinions all the time. So putting aside the authoritative position Bob holds with 30+ years of design and research in digital audio, your attempts to position us us as saints who never post opinions, and folks who have published such papers at AES do is non sequitur. Yes, as with everyone he expresses his opinions at times based on wisdom he has gathered in this field. That alone doesn’t make what he says wrong unless we can demonstrate his science is wrong.
On the topic of opinion, how about this statement from Monty in his Xiph article:“It's true enough that a properly encoded Ogg file (or MP3, or AAC file) will be indistinguishable from the original at a moderate bitrate.”
Indistinguishable at moderate bit rate? What is a moderate bit rate and where is the data to prove that?
The technical truth is that "There is very little hard evidence to suggest that it is important to reproduce sounds above 25kHz." The OSAF is that "Instead there tends to be a general impression that a wider bandwidth can give rise to fewer in-band problems." In fact many careful workers have encountered serious problems with audible artifacts due to excessive bandwidth.
The key sentence above is: "... unnecessary reproduction of ultrasonic content diminishes performance."
Enough said, eh? ;-)
Not at all. Indeed, he didn’t say enough. This was of the most disappointing parts of Xiph article for me. Here is what he says:"The effect is very slight, but listening tests have confirmed that both effects can be audible."
I can't find any reference he provides for that. Maybe there are such tests and if so, I love to read them but for now, you don’t say there are listening tests and not at least mention them by name.
As to the graph above, he assumes the 26.5 Khz ultrasonic tone to have the same amplitude as the music signal at 7 KHz (green and red bars respectively). This can happen with SACD with its noise shaping but probably very rare with naturally recorded PCM music. If it does happen in real music, are we supposed to chop it off as to take it easy on our equipment?
Look at it this way. Are we to believe that we can design audio systems that have inaudible distortion if the frequency response up to 22.5 Khz of CD, but somehow fall flat on our face if we bump that up just 16% to 26.5 KHz? You won't find anecdotal type data points like this in Bob's paper.
Again, let me repeat that Bob's paper is much in support of this article in grand scheme of things rather than the other way around. It is just that if you are going to read something like this, read Bob’s paper which is from someone who has designed such equipment and has far more credentials in this field than Monty. For a web article, Monty's article is very good but let's not be so biased as to put his effort forward as A+, and people whose shoulders he is standing on, much lower, just because they dare setting a more solid standard for audio.
Bottom line is what I said: music product in the studio is not 44.1 Khz/16-bits. If folks are not troubled by the bandwidth and storage costs, let's let them have what is produced there. Folks like yourself can chop it down to the resolution you like. And others can leave them as is. The notion that in this day and age we should stick to the CD spec as if that exact sampling rate was magic, when we don't use that medium anymore in digital distribution, is antiquated in my opinion