24/96 releases sometimes just upscaled 16/44? Options

[jamie_P84]

I know many people have developed a special attachment to the CD format - its 16-bits, 44.1kHz sample rate, and its simple interpolation of missing samples to "hide" its read errors represent an almost God-like perfection. This not only brings a great deal of comfort and reassurance to its devotees, but gives the format a unique property or 'essence' which means it can never be bettered.

As one of the deluded and unenlightened heathens who finds himself unsatisfied with CD, I can only beg my superiors to show mercy in shielding me from biased moderation, and from attacks upon my audio equipment, my hearing, my sanity and my brain's ability to adequately perceive not only sound, but the rest of the universe around me.

With that in mind, I have the following quick question:
For test purposes I have acquired a small number of 24-bit 96kHz lossless audio files derived from DVD-A and SACD releases. However, a spectrum analysis of their content always shows a sharp roll-off at either 22050Hz or 24000Hz, suggesting that these releases are nothing more than upscaled versions of previous 16-bit 44.1 or 48kHz releases (complete with the so-called 'loudness war' compression in most cases).

So, is it normal for these high resolution releases to be upscaled?
Which DVD-Audio/SACD releases are known to be genuine 24/96?

Thanks,
jamie.

This post has been edited by db1989: Jun 5 2012, 00:54

Reason for edit: Stop it. Reference: http://hydrogenaudio.org/forums/?showtopic=95366

[uart]

I don't know the answer to your specific tracks. I've heard that it's been done before, releasing "high definition" audio that is just up-sampled from normal CDA.

I'm not sure that you can tell from just the band limiting though. There are two separate issues with 24-96 compared with 16-44.1 CD audio. (1) The lower quantization noise, and (2) the greater bandwidth. They're not completely unrelated though, you can use the extra bandwidth to extend the normal audio content into the ultra-sonic region, or you can use it (via dithering) to increase the effective bit depth. In the latter case, you may well still see sharp roll off at the limits of the audible spectrum, but some additional (dither) noise at much higher frequencies.

All the listening tests I've seen show that 24-48 is pretty much indistinguishable from 16-44.1 at normal listening volumes, but I guess you already knew that.

This post has been edited by uart: Jun 3 2012, 15:13

[Kohlrabi]

So, is it normal for these high resolution releases to be upscaled?

I can see two reasons why this occurs:

1. The mastering engineer in charge knows his stuff and has realized there is no point in reproducing ultrasonics on the consumer end
2. The mastering engineer doesn't know his stuff

From my past experience, either of these two is likely. Though if the masters have "loudness wars" style mastering, 2. is more probable.

This post has been edited by Kohlrabi: Jun 3 2012, 17:04

[jamie_P84]

I'm not sure that you can tell from just the band limiting though. There are two separate issues with 24-96 compared with 16-44.1 CD audio. (1) The lower quantization noise, and (2) the greater bandwidth. They're not completely unrelated though, you can use the extra bandwidth to extend the normal audio content into the ultra-sonic region, or you can use it (via dithering) to increase the effective bit depth. In the latter case, you may well still see sharp roll off at the limits of the audible spectrum, but some additional (dither) noise at much higher frequencies.

Your latter case did occur to me, but if it's a native 24-bit recording, actual bit depth is relatively plentiful to begin with
In addition, one might ask "Why would the engineers just happen to always choose 22.05 or 48 for the intentional roll off point?".

[greynol]

It might be worth considering whether this "problem" was discovered through the auditory senses or the visual senses.

[krabapple]

So, is it normal for these high resolution releases to be upscaled?

Let's say it's not that unusual. But the fact that you have 'always' seen it, every time you look, seems unusual to me. How big is your sample?

Which DVD-Audio/SACD releases are known to be genuine 24/96?

I don't know know that there is a list today of such things. ISTR seeing a website in the heyday of DVDA/SACD that did tabulate 'real' format information for dozens of releases.

I've analysed 2channel rips of some DVD-As in my own collection, and there were certainly some with > 22kHz spectral content, and also >24kHz IIRC. With SACDs it's a bit harder to tell because instead of ripping I have to capture those from analog output and redigitize at a high SR/bit depth to detect trans-Redbook content.

This post has been edited by krabapple: Jun 3 2012, 17:47

[krabapple]

Here's one. From Neil Young's "Harvest ' DVDA, which has nominal 192kHz sample rate (Neil Young is utterly ridiculous when it comes to audio) , 24bits

No real musical content above 20 Hz or so, but the visible 'cutoff' for background noise -- the faint purple/blue speckling going completely to black -- is slightly above 40kHz, suggesting that perhaps the 'effective' SR was 88.2.



This post has been edited by krabapple: Jun 3 2012, 18:01

[uart]

I've analysed 2channel rips of some DVD-As in my own collection, and there were certainly some with > 22kHz spectral content, and also >24kHz IIRC. With SACDs it's a bit harder to tell because instead of ripping I have to capture those from analog output and redigitize at a high SR/bit depth to detect trans-Redbook content.

You must a have a really high end analog set up krabapple. I cant even get true 16 bit SNR from any of my analog captures.

BTW all. I don't see the OP as being condescending, more just a bit defensive.

[jamie_P84]

Let's say [upscaled content] it's not that unusual. But the fact that you have 'always' seen it, every time you look, seems unusual to me. How big is your sample?

Relatively small thus far - I've been hunting around for genuine 24/96 content, having just bought myself an "M-Audio Audiophile 2496" soundcard (it must be good, because it says "audiophile" on the box, right? ).

I don't know know that there is a list today of such things. ISTR seeing a website in the heyday of DVDA/SACD that did tabulate 'real' format information for dozens of releases.

A list would certainly be helpful - confirmation from the record labels would be even more helpful!

[uart]

Here's one. From Neil Young's "Harvest ' DVDA, which has nominal 192kHz sample rate (Neil Young is utterly ridiculous when it comes to audio) , 24bits

No real musical content above 20 Hz or so, but the visible 'cutoff' for background noise -- the faint purple/blue speckling going completely to black -- is slightly above 40kHz, suggesting that perhaps the 'effective' SR was 88.2.

Thanks for posting that. Not having any HD content myself, I was interested to see a spectrograph.

Given that "Harvest" is rather old, what would that have been mastered from krabapple, the original tapes?

BTW. You can just make out a faint line in that spectrum at about 30 kHz, I wonder what that is?

[Nessuno]

I find this obsession for ultrasonic frequencies absurd!

Let's rest on a pure analogic field: what content do you expect to find in music at frequencies higher than what players themselves hear and so are able to intentionally produce, and composers to write in the first place?
Only, if something, higher harmonics of the highest tones they could play, quite low in energy compared with audible content and maybe completely masked before they reach a transducer.

Given the ouverture of the OP's first post, I put it in a philosophical way: I think that brickwalling music at 20kH makes it more faithful to what the composer had in his mind when he wrote it!

This post has been edited by Nessuno: Jun 3 2012, 18:25

[jamie_P84]

Thanks for posting that. Not having any HD content myself, I was interested to see a spectrograph.
Given that "Harvest" is rather old, what would that have been mastered from krabapple, the original tapes?

Thanks from me also - I might purchase a copy of "Harvest".
Original analogue master tapes will certainly contain content above 24kHz, and a level of depth beyond that of 16-bits.

[krabapple]

You must a have a really high end analog set up krabapple. I cant even get true 16 bit SNR from any of my analog captures.

Analog wasn't involved in the spectrogram I showed That file was ripped as digital data directly from the DVD-A, and Audition is just displaying what's in the file...not what comes out of my speakers.

For SACD, the signal is from an Oppo 970 2channel analog out, which I can capture at a variety of sample rates up to 192kHz, at 24 bits with my M-Audio card. I've tried it at the highest SR just because I can, but I can't hear past Redbook, so mostly I stick to 88.2 for 'archiving' the audio. I seem to recall that the Oppo always converts DSD to 88.2 PCM anyway, so capturing at anything higher than that is doubly pointless.

This post has been edited by krabapple: Jun 3 2012, 19:14

[krabapple]

Original analogue master tapes will certainly contain content above 24kHz, and a level of depth beyond that of 16-bits.

Why do you believe that?

[krabapple]

Given that "Harvest" is rather old, what would that have been mastered from krabapple, the original tapes?

Yes. Not because DVDA/SACDs always are from master tapes, but because Neil Young is kind of fanatical about such things.

BTW. You can just make out a faint line in that spectrum at about 30 kHz, I wonder what that is?

IIRC, it's noise from video monitors or TVs that were in the recording studio -- you see that line on a number of old recordings. Either that, or its a tape bias signal, I don't recall which. (I think a bias signal is typically higher than that though)

[krabapple]

Here's another -- Deep Purple Machine Head DVDA. Nominal 96kHz SR, 24 bits





That video noise @ ~29kHz is crazy looking on this one!

[bandpass]

Original analogue master tapes will certainly contain content above 24kHz, and a level of depth beyond that of 16-bits.

ATR Master Tape Specifications: http://www.atrtape.com/technical.php

Frequency Pass Band 20Hz-20Khz
Peak Dynamic Range 86 dB

[Nessuno]

Frequency Pass Band 20Hz-20Khz
Peak Dynamic Range 86 dB

Oh, but wait! Somewere else on their site they state: "The highest digital resolution today offers 4,608,000 bits switching per second. Not bad. Big improvement over the standard Red Book CD but it is not even close to sub-micron particle resolution of ATR Master Tape."

So, where's the truth?

[jamie_P84]

ATR Master Tape Specifications: http://www.atrtape.com/technical.php

Frequency Pass Band 20Hz-20Khz
Peak Dynamic Range 86 dB

Probably means a flat frequency response and linearity from 20Hz-20Khz within pre-defined tolerances. Unlike digital recorders, analogue ones do not require a sharp cut-off in frequency response above their rated maximum.
I have many AAD CDs which show no signs of roll-off at 20kHz, incidentally.
Dynamic range of analogue vs digital cannot be compared so easily either - the former can provide subjectively useable dynamic range which exceeds that of its digital equivalent, because it 'fails gracefully' above its rated maximum range, continuing to capture information which, in the digital domain, would have simply been truncated (resulting in a clipped waveform).

PS. It would be rather unfortunate if this thread were to turn into "yet another analogue vs digital debate", all because my original post insulted certain people's "religion".

[jamie_P84]

BTW. You can just make out a faint line in that spectrum at about 30 kHz, I wonder what that is?

IIRC, it's noise from video monitors or TVs that were in the recording studio -- you see that line on a number of old recordings.

Interesting thought. Noise at the line frequency of the TV signal (eg. 15.625kHz in the case of PAL TV) is commonly found on studio recordings. I've even seen noise at 10.125kHz on some vintage British recordings - the line frequency of the old British 405-line system.

[greynol]

PS. It would be rather unfortunate if this thread were to turn into "yet another analogue vs digital debate", all because my original post insulted certain people's "religion".

Then why are you attempting to do so (albeit poorly)?

Religion?!? I fear you have it the wrong way around. I guess this is another sign of what uart is labeling as being defensive.

If you don't like our rules or what this community has to say, perhaps you can find somewhere else to post.

This post has been edited by greynol: Jun 3 2012, 23:22

[Porcus]

That video noise @ ~29kHz is crazy looking on this one!

If it is video noise (and not bias) then that means it could be recorded? Interesting (but not very relevant).

[jamie_P84]

Your latter case did occur to me, but if it's a native 24-bit recording, actual bit depth is relatively plentiful to begin with
In addition, one might ask "Why would the engineers just happen to always choose 22.05 or 48 for the intentional roll off point?".

Typo - should've read "22.05 or 24 for the intentional roll off point", but I'm sure you all knew that.

[Ron Jones]

The last Nine Inch Nails album, The Slip, had a few 16-bit tracks included as part of the 24/96 release, but the issue was discovered (by a member here), attributed to a mastering error, and the album was quickly re-released with corrected files. Had no one used tools to inspect the files, it's unlikely anyone would have discovered the issue.

Now, if you don't mind, I must pray at the altar of science in shame.

[krabapple]

Probably means a flat frequency response and linearity from 20Hz-20Khz within pre-defined tolerances. Unlike digital recorders, analogue ones do not require a sharp cut-off in frequency response above their rated maximum.

True, they don't but that doesn't mean they are 'flat' or distortion-free in that range. That is the point, I would think. LPs have a FR that extends beyond 20kHz, but what's there, at what level, and how distortion-free is it?

I have many AAD CDs which show no signs of roll-off at 20kHz, incidentally.

So, how have you determined that these CDs you refer to have 'no signs of rolloff' at the redbook limit?

Dynamic range of analogue vs digital cannot be compared so easily either - the former can provide subjectively useable dynamic range which exceeds that of its digital equivalent, because it 'fails gracefully' above its rated maximum range, continuing to capture information which, in the digital domain, would have simply been truncated (resulting in a clipped waveform).

'fails gracefully? "subjectively usable dynamic range'? capturing extra 'information'?

Ok let's run with all that. What is the 'subjectively usable' range that analog tape offers, how many people listen to the original analog tape, and what is the subjectively usable DR that dithered, noise-shaped Redbook offers as a delivery format, and what is the subjectively usable DR that LP or reel-to-reel consumer formats offer? What is the background noise level of a typical listening room?

PS. It would be rather unfortunate if this thread were to turn into "yet another analogue vs digital debate", all because my original post insulted certain people's "religion".

PS I took you not to be a troll, but now I wonder.

This post has been edited by krabapple: Jun 4 2012, 06:58