Technical question re. SHM-CD, Blu-spec CD & Digital Files

[Rango]

Before we get into this: I know the basic argument is that it's all down to the mastering, and while I do believe that's true to a very great extent (I think) the question still stands...

...essentially, my question is this: do you get an uplift in audio quality by ripping a file from a disc?

You'd be forgiven for having the knee-jerk reaction of "of course not", but hear me out...the reason I ask is this:

The idea behind SHM-CD is that the material they're manufactured from allows a CD player’s laser to get a better reading as it passes across the notches etched into the disc…

I’ve also read that there’s only an advantage to SHM-CD's if you’re playing the physical disc in a CD player, because it's designed purely to allow the laser to get a better read while passing over the etched notches in real-time…

…In other words, if an SHM-CD and a regular CD both have exactly the same contents, while the SHM-CD may sound better when played by a CD player, you’ll get the same quality rip from both discs regardless.

This would seem to suggest that files ripped from either an SHM-CD, or just a regular CD, could potentially sound like they're of higher quality than the disc they were ripped from...because, rather than the drive trying to read the data in real time over one pass, the drive that's ripping from the disc is (presumably?) taking the time to read all of the information from the disc to create an exact image of the information on the disc.

With regard to SHM-CD's, according to wikipedia "since the CD-Audio format contains inherent error correction [...] it is not known whether the difference in read errors [with SHM-CD] is great enough to be audibly different." which - in itself - suggests that the real-time laser-reading of a disc is inherently prone to error.

While SHM-CD's rely on polycarbonate originally developed for LCD screens to aid a better, real-time reading of the disc by the disc-player's laser, Blu-spec CD's use a combination of "polymeric polycarbonate resin" (Blu-spec CD2 would later use silicone wafers) and a Blu-ray authoring laser for a finer etching process to produce more precise notches that reduce playback errors...

...again, we're seeing technological measures taken to reduce errors in the real-time, laser-reading of the physical disc, which does seem to suggest that an exact image of the content of a disc for digital playback can give you a higher quality output than you'd get from a player using a laser to read a disc in real-time.

What's the thinking on this? Are there already theories on this? If not, what do people think?

My own anecdotal input:

While it seems the response to Blu-spec CD & Blu-spec CD2 varies, I personally have Mountain's Nantucket Sleighride, on both regular CD, Blu-spec CD, and Blu-spec CD2. The Blu-spec CD2 seems granularly better in quality than the Blu-spec CD, and the Blu-spec CD seems granularly better in quality than the regular CD. I'm wondering if there's another, at least granular, increase in quality to be had from ripping the Blu-spec CD2, and indeed whether it's possible to get an uplift in quality when ripping just regular CD's.

What do people think?

 

[splinter]

My own anecdotal input:

With all due respect, but did you come to these conclusions in a blind test? Because otherwise you might hear what you want to hear (which is a very common thing in audio).

There is no factual (in the sense of scientifically valid) indication that anyone can hear a difference between these disc production methods (given that they contain the same audio data etc). Bit errors while reading CDs are corrected by the built-in error correction, and even if not they are usually not detectable through listening. Although the companies claim that these production methods reduce jitter, this is not the case (jitter does not occur in the physical layer of the laser "touching" the storage medium).

The digital data received from these CDs is always the same. So your initial question is based on a wrong assumption.

 

[jimfisheye]

The data in a file is a matter of fact thing. It's either fully intact or not. Not intact can be full dropouts - ie. truncated slices of time or artifacts from error correction pushed beyond the threshold of fully correctable errors.

The output from a media player - stand alone disc player or computer system - is fed to DACs. The quality of those DACs is the final hardware component.

Dropouts or artifacts from incomplete error correction are more accurately mechanical errors. Akin to scratches on vinyl. We don't qualify fidelity with mechanical error riddled program. 'Audiophile' fidelity is in the hands of the output DAC. The chip decoding the ones and zeros and the op amps and capacitors in the analog output stage. The bits you would critique for signal to noise and so forth.

So a stand alone disc player has the DAC it was built with. Or you can output digitally and use your own or build a computer system with your choice of DAC.

Everything mentioned from different brands of media to different production plants all boils down to the same question: Full data or errors? Is the system working or not? It's only a yes/no answer. Fully analytical.

There's no quality of fidelity discussion beyond the output DAC used. The data is either delivered intact or any artifacts in the sound should be dismissed as "The system is broken. Hit stop." In the same spirit that you don't critically review a speaker with a blown tweeter. There's never a fidelity skew with digital; eg. muddy, bright, tinny, etc. The data is being decoded and fed to a DAC or not.

Trying to read any magic into this data shuffle is like calling out the published circuit/system designs as being misleading or something. Or having hidden function. Some consumer AVR products might have some misleading brochure speak. Something might be hit with an extra DA -> AD conversion. The higher end stuff will note the internal routing in the specs and home theater on PC is you making those connections yourself.

Data delivery (yes/no)
DAC circuit quality
That's all we're talking about here.

Digital files come with a nice clean ckecksum to verify. A hard yes/no for file integrity. We like this! Discs are scary with extra data (room pending) because it's not "if" but "how many" errors will occur in production. Maybe most get corrected? And these are extra insidious because you don't see media quality degrading over time. We hates them!

But the audio quality doesn't do anything. You get dropouts or chirpy artifacts from error correction pushed too far.

 

[Rango]

With all due respect, but did you come to these conclusions in a blind test? Because otherwise you might hear what you want to hear (which is a very common thing in audio).

I'm nothing if not a sceptic and I'm familiar with power of suggestion and confirmation bias and I was very mindful of these while making the comparison, but I agree there's always room for cognitive biases...

...while I did swap discs so many times that I lost track of which was which and reached a point where I thought I'd fooled myself, only to find that I'd just mistaken one disc for another (or was my subconscious keeping track?), the problem is, there's nothing to say that the Blu-spec CD's and/or the SHM-CD's don't just contain a better re-master, so unless the discs literally carry exactly the same information, there's never really going to be a way to make an accurate comparison, blind or otherwise?

...I had meant to mention that in the opening disclaimer but neglected to.

The digital data received from these CDs is always the same. So your initial question is based on a wrong assumption.

That's a very bold statement and kind of the crux of what I'm asking...?...can we really assume that that is the case?

Essentially, my contention is this: that if making a CD from a different material can create a noticeable difference in audio quality, because it aids the laser in getting a better reading of the disc's data in real-time, then it would follow that you could get an uplift in audio quality by ripping a disc to replace the real-time, laser-based reading process with a lossless digital reading.

The data in a file is a matter of fact thing. It's either fully intact or not.

But that bypasses the question entirely? While that statement is indeed correct, the question is about the mechanism by which the data is physically read from the disc, not what happens to it afterwards?

If you meant to say what splinter wrote above: "The digital data received from these CDs is always the same." then, again, a very bold statement but can we really just assume that that's the case?

Splinter also writes:

There is no factual (in the sense of scientifically valid) indication that anyone can hear a difference between these disc production methods (given that they contain the same audio data etc).

Is this because no scientific tests have been conducted...?...that there are no conclusive results because it's all anecdotal...?

...I would argue that it's probably impossible to tell from comparing discs because there's no guarantee that the data on two different releases is the same, as they seem to write newly remastered files to these kinds of discs, so that's always going to be an "apples to oranges" comparison; I think probably the best way to test it is to just rip a disc and make a comparison between the disc and the ripped file.

Looking (sceptically) at the whole thing from another perspective: it would be easy to ask why companies such as Sony would go to so much time, effort and expense in R&D and re-tooling their factory automation to produce discs that don't actually have an added benefit, when they could just take a little more time and care with the remastering, but to be sufficiently sceptical, I guess, if it is snake oil, and people buy into it, then the return on the investment might justify the costs.

Also, we might ask why they don't just move to DVD or SACD or just go straight to Blu-ray, but I'd imagine that CD's installed base is probably larger than the installed base of DVD-A, SACD and Blu-ray Audio will ever be, unless new generations of listeners migrate back to physical media...but who knows.

 

[jimfisheye]

But that bypasses the question entirely? While that statement is indeed correct, the question is about the mechanism by which the data is physically read from the disc, not what happens to it afterwards?

Correct! The question in question is weather or not the data transfer from the media is working. This is the first question in a playback system and it's a yes/no question.

It's a good question! Not really stupid. When you don't know something, you don't know. Again, we don't review a broken thing and make a quality assessment on the broken part as though it was genuine intentional effort.

"I don't like Pink Floyd - The Wall because the scratch in Mother makes it skip and repeat in a spot." "I don't like the sound of this disc format because my player gets errors from them and dropouts degrade the listening experience."

Dropouts or corrupt data = broken! No review or critique possible.

Now if your premise is that one of these formats or manufacturing processes is ALWAYS broken, that would be fair enough. (Shots fired and all.) But you have to talk about the thing being broken and not describe it like a quality shootout between analog devices. The media and device are delivering a file of ones and zeros. The DAC you happen to choose to listen with is the device you can critique for analog audio quality.

 

[splinter]

can we really assume that that is the case

Yes, because that is the base assumption of digital data storage. And as I said before: even if that was not the case, you would either hear no difference (because single bit errors are not noticeable by ear after digital-analog-conversion), or you would hear obvious errors (like real audio glitches), or you would hear noise (from jitter), but in no case you will hear "an uplift in audio quality".

contain a better re-master, so unless the discs literally carry exactly the same information, there's never really going to be a way to make an accurate comparison, blind or otherwise

You can rip the discs and do a null test, then you know whether it is the same master or not. You will need some basic knowledge on audio processing to be able to do that, but it is not really complicated. If it is not the same master, then the listening comparison is moot. If it is the same master... read on:

Is this because no scientific tests have been conducted...?

Yes (I guess, as a short Google search brought no results), and that is because everybody who has some understanding of the involved technology knows that it cannot lead to any interesting results. There is a defined 16 Bit / 44.1 kHz PCM signal encoded on the discs, which is restored perfectly when reading the disc, be it on a computer or on a hifi player. There is a multitude of measures to make sure the restoration of the data is correct. These measures have been specified in the advent of CDs, and new production methods do not change that. So in the end you will have the same data, no matter if it was read from a standard CD, SHM-CD or Blu-Spec CD. You can even compare the data digitally. Why then make the effort and do a listening comparison test if you know before you are listening to the same data?

That is the reason why nobody carries out such a test.

why companies such as Sony would go to so much time, effort and expense

It is just a marketing stunt. They use their existing technology or stuff they can easily adjust in the production process; e.g. use "Blu-ray technology" to create CDs - of course you can dig larger holes with smaller shovels, and if it does not take you longer and you have a lot of small shovels at hand, why not do it? And then they sell that as quality improvement - which it might be from a technological point of view. But you cannot sell to customers that the pits on the disc are more defined now because they were made with better equipment. So they imply that this also contributes to the audio quality - which obviously some people want to believe and hear.

I am sure quite a lot of SHM and Blu-spec releases are intendedly based on new masters so that there is an audible difference. But the difference is not there because of the production process, but because of the audio mastering. But if you sold that under a label long enough, people will believe that SHM or Blu-spec stands for "better audio quality". This is mainly directed at the Japanese market, which I have no real knowledge of, but I suspect there are a lot of consumers there who are suspectible to this kind of promise.

why they don't just move to DVD or SACD

SACDs and DVD-As need a fundamentally different production process. SACD has a different audio encoding already (DSD instead of PCM), so the difference already lies in the audio production stage. AFAIK, Sony DADC Austria is the last production facility that is even able to produce SACDs. New player hardware is rare. But there is still a small market (mainly - again - in Japan).

DVD-As could probably be produced in normal DVD plants, but as there are no players being produced anymore... this format has been dead for a long time.

With Blu-ray audio and high-res streaming there is also no need for those formats. And keep in mind: no high-res format ever gained a market saturation that is really relevant compared to other audio formats. So this is and stays a niche market.

But if I want to sell something into that niche that does not cost me much, why not pimp up the marketing on regular CDs? Maybe I can even win over some new customers, because they already have the playback equipment at hand (in contrast to SACD or DVD-A). That is exactly what is happening here. Win over CD listeners to buy the same CDs again. As the "Remaster" label is burnt by the loudness war, they now created a new label that leads the focus on CD production, so technical "innovation" that looks "objectively" better and does not rely on some dubious mastering engineers. And this is even harder for the consumer to tell: how do you know that your "Blu-spec CD" was really produced with BR technology? How do you know that the polycarbonate material of your SHM CD is really different to the material on you other CDs? There is no way for the consumer to tell! It is belief only. So they invest something to nurture this belief (a couple of better sounding masters sold exclusively on Blu-spec CDs), and then they cash in on it.

 

[jimfisheye]

When a tweeter is blown in a speaker, we don't do a nuanced listening test. We measure the coil with an ohm meter, say "Yep, blown!" and replace it.

When a digital music file serving device is not able to serve data 1:1... we investigate that failure point. We don't critique the sound of dropouts or data loss correction attempts.

The disconnect is not realizing the data delivery step is an analytical absolute. Treating the system as a mystery and attributing what are matter of fact failures as a perceived intentional range of operational quality.

As stated in some of the replies, the first thing to discuss is the digital data set you got from the device reading the media and your initial null tests against other rips. This was skipped over as though it wasn't even understood.

Some of these AVR and stand alone style devices might have some mystery routing inside, or data reductions or conversions here and there. There could be lossy stuff going on. Poor man's copy protection or whatever you want to call some of that. "Cheapness" covers a lot of ground. This is why some of us love the computer for audio and loathe the 'mystery boxes'!

 

[Rango]

The disconnect is not realizing the data delivery step is an analytical absolute.

On the contrary, that directly relates to the core of the question.

To summarise, as I understand it: you guys are saying that there's no loss of data and therefore no loss of quality from the real-time playback of a CD.

@splinter, thanks for your thoughts re. the various formats; here are mine again for the record:

Looking (sceptically) at the whole thing from another perspective: it would be easy to ask why companies such as Sony would go to so much time, effort and expense in R&D and re-tooling their factory automation to produce discs that don't actually have an added benefit, when they could just take a little more time and care with the remastering, but to be sufficiently sceptical, I guess, if it is snake oil, and people buy into it, then the return on the investment might justify the costs.

Also, we might ask why they don't just move to DVD or SACD or just go straight to Blu-ray, but I'd imagine that CD's installed base is probably larger than the installed base of DVD-A, SACD and Blu-ray Audio will ever be, unless new generations of listeners migrate back to physical media...but who knows.

 

[jimfisheye]

To summarise, as I understand it: you guys are saying that there's no loss of data and therefore no loss of quality from a real-time playback of a CD.

I'm saying that if there IS a loss of data from real-time playback of a CD with a stand alone hardware CD player... there's your problem right there! It's not a subjective quality issue. The system is matter of fact literally malfunctioning.

It might be difficult to investigate and make that call sometimes! Audio quality being subjective and all and some music mixes even containing distorted elements. Some consumer devices are difficult to operate and some rogue devices are even made to obscure their 'cheapness' in weird ways. There are even some devices delivered DOA with design flaws. (The facsimile/bootleg age we live in.)

 

[Rango]

I'm saying that if there IS a loss of data from real-time playback of a CD with a stand alone hardware CD player... there's your problem right there! It's not a subjective quality issue. The system is matter of fact literally malfunctioning.

It might be difficult to investigate and make that call sometimes! Audio quality being subjective and all and some music mixes even containing distorted elements. Some consumer devices are difficult to operate and some rogue devices are even made to obscure their 'cheapness' in weird ways. There are even some devices delivered DOA with design flaws. (The facsimile/bootleg age we live in.)

Right, but making the assumption that you don't have a faulty piece of equipment, then the summary stands, right...?

The summary...

To summarise, as I understand it: you guys are saying that there's no loss of data and therefore no loss of quality from the real-time playback of a CD.

 

[splinter]

there's no loss of data and therefore no loss of quality from the real-time playback of a CD

That is (generally) correct (assuming a device functioning within the red book specified limits). And if there was, it would be different from what you expect/describe here. It would just sound faulty, not more lo-fi.

Comparing live CD playback with digital file playback by listeing is of course very hard to objectively achieve, because you start with different DACs. But as shown above, because of the nature of digital data there is no need to do such a comparison anyway.

 

[jimfisheye]

I'm saying we have to segregate data delivery and DAC quality to be able to talk about this. DAC quality is the subjective part. DACs include analog signal handling circuits. We can qualify analog signal devices with noise, distortion, etc specs. The data delivery with digital data is a matter of fact on or off discussion.

There's no difficulty in delivering audio data dropout free. This isn't a technical struggle. So, no, if there's no loss of data then there's no loss of quality from the real-time playback of a CD. And the DAC you choose to use to derive the analog signal from the digital codes is what it is. That's the piece of hardware you could conceivably upgrade and hear better reconstruction of the digitized analog signal. (You'll probably find that this is a diminished returns kind of thing. Unless you have some ratty cheap DAC... Think Worst Purchase or Amazon product.)

Anyway, the playback DAC is subjective. Data delivery is a hard yes/no.

 

[Rango]

I'm saying we have to segregate data delivery and DAC quality to be able to talk about this.

To be completely honest, I don't really agree on that point at all; you just seem to want to ignore my question entirely and segue into talking about DAC's...

Edit: @jimfisheye...are you suggesting that my media player has different DAC's for playing CD's and files it plays from a data stick?

That is (generally) correct (assuming a device functioning within the red book specified limits). And if there was, it would be different from what you expect/describe here. It would just sound faulty, not more lo-fi.

Comparing live CD playback with digital file playback by listeing is of course very hard to objectively achieve, because you start with different DACs. But as shown above, because of the nature of digital data there is no need to do such a comparison anyway.

You confused me with that last part, but otherwise, thanks.

It's hard to know with whom the burden of proof lies with a question like this...the company making the claims about their technology or the consumer/"prosumer" disputing it...

...when the best supporting argument on both sides is "just trust us", it's difficult to have a lot of faith in either position. ;0)

 

[stoopid]

Anyone interested in whether we can perceive anything past CD standard audio quality should read and comprehend this article. It lays out very well why any 'benefit' 99% of listeners hear is placebo. [this is especially true for any formats that claim one CD quality format is superior to another CD quality format]

This topic has been beaten to death on countless music forums and social media. When in doubt, trust in the scientific method/process until proven otherwise.

 

[stoopid]

...when the best supporting argument on both sides is "just trust us", it's difficult to have a lot of faith in either position. ;0)

You can't disprove something that doesn't exist. I believe in dragons. Prove me wrong.

 

[Rango]

Anyone interested in whether we can perceive anything past CD standard audio quality should read and comprehend this article. It lays out very well why any 'benefit' 99% of listeners hear is placebo. [this is especially true for any formats that claim one CD quality format is superior to another CD quality format]

This topic has been beaten to death on countless music forums and social media. When in doubt, trust in the scientific method/process until proven otherwise.

Okay, hang on, wait...what?!...

4 A NOTE ON HIGH-RESOLUTIONRECORDINGS

Though our tests failed to substantiate the claimed advantages of high-resolution encoding for two-channel audio, one trend became obvious very quickly and held up th roughout our testing: virtually all of the SACD and DVD-A recordings sounded better than most CDs—sometimes much better. Had we not “degraded” the sound to CD quality and blind-tested for audible differences, we would have been tempted to ascribe this sonic superiority to the recording processes used to make them.

So...what exactly are they testing here?

3 CONCLUSIONS

We have analyzed all of the test data by type of music and specific program; type of high-resolution technology; age of recording; and listener age, gender, experience, and hearing bandwidth. None of these variables have shown any correlation with the results, or any difference between the answers and coin-flip results. The previous work cited, some of it at the very beginning of the CD era and some more recent, pointed toward our result. With the momentum of widespread “high-rez” anecdotes over the last decade, culminating in the Stuart assertions, we felt the need to go further and perform a thorough, straightforward double-blind level-matched listening test to determine whether 16/44.1 technology would audibly degrade the sound of the best high-resolution discs we could find. We used a large and varied sample of serious listeners; we conducted our tests using several different types of high-quality playback systems and rooms; and we took as much time as we felt necessary to establish the transparency of the CD standard. Now, it is very difficult to use negative results to prove the inaudibility of any given phenomenon or process. There is always the remote possibility that a different system or more finely attuned pair of ears would reveal a difference. But we have gathered enough data, using sufficiently varied and capable systems and listeners, to state that the burden of proof has now shifted. Further claims that careful 16/44.1 encoding audibly degrades high resolution signals must be supported by properly controlled double-blind tests.

I'm assuming they didn't degrade the sound of the various types of CD they were testing, just the SACD & DVD-A.

You can't disprove something at doesn't exist. I believe in dragons. Prove me wrong.

Yes, I know...unicorns in equador; The Flying Spaghetti Monster; Russell's Teapot, etc. ...I think you're misreading me.

 

[stoopid]

Okay, hang on, wait...what?!...

So...what exactly are they testing here?

You didn't read the whole article, they explain why that is (hint: it's not the resolution of the playback material).

There's no cliff's notes or cherry picking if you actually want to know something, you came into this having already drawn conclusions so now it's the planet's obligation to change your mind. I personally have zero interest in doing that, but I will present info even if you apparently don't want to read 5 pages.

 

[jimfisheye]

To be completely honest, I don't really agree on that point at all; you just seem to want to ignore my question entirely and segue into talking about DAC's...

Your question is non sequitur. I'm just the messenger on that. I didn't conceive of and design these systems. If you are genuinely inferring that the operation of this stuff as published is misleading and suggesting I'm thus quoting incorrect information, that would be a very extraordinary claim. 40 years of PCM digital and devices and media out in the world and all and no apparent benefit for subterfuge of that scope.

Edit: @jimfisheye...are you suggesting that my media player has different DAC's for playing CD's and files it plays from a data stick?

No.

I mentioned that a listener can choose to purchase any DAC product they wish and pipe their digital media to it.

 

[Mr. Afternoon]

Mastering. It's all about the mastering.

One good comparison would be to find one of these SHM-CDs that has the EXACT same master as a normal CD and then compare...then you get practical proof. However, as far as I'm aware, most of these new SHM-CDs are derived from better (like first-gen tape scans) masters than previous CDs, and are louder too (because of Sony's policies with uncompressed audio).

SACD, DVD, and Blu-ray all have stronger error correction to the point where this is not needed. However, I haven't run into a regular CD yet that struggles with data reads...

 

[Rango]

...you came into this having already drawn conclusions...

That's absolutely not true. I came here with a question; I didn't post it to start a row or to be attacked; I'm just trying to keep things light; this isn't supposed to be a fight.

Your question is non sequitur.

No it's not; it's a perfectly legitimate question.