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

[Mr. Afternoon]

Also, if I remember correctly, a CD can theoretically hold 2-3GB of data, but that's reduced down to 700MB because of the error correction...

 

[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, so...we're not talking about regular CD's in this thread, and the study is talking about how confining high-resolution media to a CD standard nutralises the benefits. I don't see how that helps in this instance.

 

[jimfisheye]

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

It is a perfectly legitimate question!

You seem to be (intentionally or not) not only questioning the published operation of these devices but calling that out as fraud. And the 40 years of tech out in the field from many manufacturers as subterfuge. But you don't actually refute the details and you provide no alternate theory. You are either dismissing the available software tools or calling fraud on that too. Strong stuff!

I mean... We are in the age of software spoofing! I'm actually one of the ones listening when anyone comes out with even seemingly outrageous premises! Want to talk about Dolby using the Atmos decoder for a 'poor man's copy protection' scheme? How about Apple's whitelists for 'approved' devices? Want to trick people? Make an error message print on the screen that says your hardware is not compatible! That's it! That's all it takes. Dolby has people running out and buying whole new AVR products with this shtick right now. You still need extraordinary evidence for your extraordinary claims.

 

[Rango]

It is a perfectly legitimate question!

But you don't seem to want to address it; you seem to just want to talk about DAC's. My question, to boil it down to it's most basic, is whether a standard CD laser is a weak link in the system and whether eliminating it in favour of a lossless digital reproduction might produce a higher quality output.

Maybe if we reframe it...how about this: why should I believe a random person posting anonymously to a forum rather than trusting the manufacturer's claims?

You've offered me an argument from authority, which basically boils down to "just trust me". Why should I believe either of you?

 

[splinter]

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

They "degraded" high resolution material to CD quality and then let listeners find out which is the real high res material and which is the degraded one. And most listeners, including trained audio engineers, did not have a significantly higher hitrate than 50%, which means they do not hear it better than someone who is just guessing.

This has nothing to do with the SHM/Blu-spec debate, but shows that the whole high res hype is mostly that: a hype most people cannot (but want to) hear.

But: the same hype argument applies to the Blu-spec discussion.

when the best supporting argument on both sides is "just trust us"

Our argument is not "just trust us". Our argument is "there is no difference in the digital data, so there is no difference in the analog signals, so every difference you hear is in your head only". You do not need to trust anyone on that, you can check that yourself on the digital level (see above, "null test").

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.

In that case you would not need to compare, because the data would be bitwise identical. Or maybe you meant that.

 

[splinter]

why should I believe a random person posting anonymously to a forum rather than trusting the manufacturer's claims?

You can believe whatever you want. But that does not change anything on the science. Best is to find out yourself. We did that, and now we gave you the hints how to do that yourself. If you prefer to believe further, that is your choice.

 

[stoopid]

Okay, so...we're not talking about regular CD's in this thread, and the study is talking about how confining high-resolution media to a CD standard nutralises the benefits. I don't see how that helps in this instance.

That's a fair conclusion, I was hoping to conjure some extrapolation of the same idea directly towards any vaporous 'audiophile' claim (of which there are too many to list here). Most of the digital technology we use in the audio-verse has been fleshed out by this point 50 years on, most of the "but what about" questions and issues have been addressed ad nauseum. The root source for these questions inevitably always stem from hardware manufacturers and the various audiophile media companies wanting to sell a product for more money. If there's no audible difference for that 99% of the human race between CD quality and higher resolution, then there's certainly less between CD quality formats as you presented them in your OP. It's not a giant leap to make. If anything, it seems like an obvious conclusion.

If you're just looking for validation of your conclusions, it doesn't seem like you're going to find it here. Maybe there's a forum with members drinking the right flavor of Kool Aid out there.

 

[Rango]

If you're just looking for validation of your conclusions, it doesn't seem like you're going to find it here. Maybe there's a forum with members drinking the right flavor of Kool Aid out there.

I'm not looking for validation or a fight; just a reasonable and civil response.

For example: "The consensus of accepted thinking seems to suggest there'd be no benefit; if you want an uplift in audio quality you could try upgrading to a receiver with a better DAC or upgrading your speakers."

...at any rate...at this point, that's my takeaway from this thread.

My thoughts re. the Blu-spec CD2s:

I don't have many data points. I have the three Mountain discs and the Stone Roses Blu-spec CD2. My speakers are entry level and my receiver isn't particularly new. I think trying to screen for cognitive bias is pointless because although I feel like there is a very granular improvement from disc to disc it could just be the mastering, so whether or not they do sound ever so slightly better it can't really tell you anything either way...

...one thing I will say, is, if that's all they've got with Blu-spec CD2...?...I'm not particularly impressed...I don't think there's enough of an improvement across those particular discs (the Mountain discs) to exceed power of suggestion and/or cognitive bias. It seems like a lot of it is just a difference in the noise floor, and not pronounced enough to shift the needle in terms of the average listener's perception...

...it could be that my system just isn't high enough spec to get the most out of them, or that there's overhead they've not been able to utilise due to the files they're working with, so, again, not particularly helpful...not really controlled conditions.

Having said that, I wouldn't give up my Blu-spec CD2's now that I've got them. I'm pretty sure there is a difference, at least on my system, even if just an extremely marginal one.

 

[splinter]

Also, if I remember correctly, a CD can theoretically hold 2-3GB of data, but that's reduced down to 700MB because of the error correction...

That seems about right:

a frame ends up containing 588 bits of "channel data" (which are decoded to only 192 bits of music).
- https://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio

The 588 bits include 192 bits audio data, 64 bits error correction data, 8 bits subcode data, and the rest is padding and merging bits created through the specific encoding of how it is written on CD to counter read errors.

So if there is 700 MB of audio data on the disc, then:
700 MB / 192 * 588 = 2143,75 MB.

Nice I did not know that. Thanks for pointing that out.

 

[splinter]

I'm pretty sure there is a difference, at least on my system, even if just an extremely marginal one.

As said before, that difference is in the mastering then and could be achieved with a regular CD as well, or it is in your head only. There is no alternative explanation.

 

[atrocity]

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

Having ripped thousands of CDs and in the process encountering many that either:

1. Played fine in a player but had trouble ripping
2. Ripped fine but had trouble in a player
3. Would only rip without error in one drive but not another

my conclusion is that the only way to 100% consistently deliver the exactly correct bits every time is by playing a file that has been verified via AccurateRip.

But having said that, in the absence of any serious issues, it seems extremely unlikely that the difference--which almost certainly exists on paper--would be audible.

 

[atrocity]

But having said that, in the absence of any serious issues, it seems extremely unlikely that the difference--which almost certainly exists on paper--would be audible.

And just to be clear: I'm talking exclusively about CDs. Due to the much more robust error correction built into DVDs and Blu-rays, I don't think the same variables apply.

 

[Rango]

They "degraded" high resolution material to CD quality and then let listeners find out which is the real high res material and which is the degraded one. And most listeners, including trained audio engineers, did not have a significantly higher hitrate than 50%, which means they do not hear it better than someone who is just guessing.

But...this:

A NOTE ON HIGH-RESOLUTION
RECORDINGS
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
throughout 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.
Plausible reasons for the remarkable sound quality of
these recordings emerged in discussions with some of the
engineers currently working on such projects. This portionof the business is a niche market in which the end users are
preselected, both for their aural acuity and for their willingness to buy expensive equipment, set it up correctly,
and listen carefully in a low-noise environment.
Partly because these recordings have not captured a
large portion of the consumer market for music, engineers
and producers are being given the freedom to produce
recordings that sound as good as they can make them,
without having to compress or equalize the signal to suit
lesser systems and casual listening conditions. These recordings seem to have been made with great care and
manifest affection, by engineers trying to please themselves and their peers. They sound like it, label after label.
High-resolution audio discs do not have the overwhelming
majority of the program material crammed into the top 20
(or even 10) dB of the available dynamic range, as so
many CDs today do.
Our test results indicate that all of these recordings
could be released on conventional CDs with no audible
difference. They would not, however, find such a reliable
conduit to the homes of those with the systems and listening habits to appreciate them. The secret, for two-channel
recordings at least, seems to lie not in the high-bit recording but in the high-bit market.

...so yeah...cognitive bias; it seems the above can be read both ways.

...but even so; they're still not testing for what I'm talking about. They have controlled conditions which don't take into account whether or not there's a laser in the chain, it's not what they're testing for; that would be a different study.

As said before, that difference is in the mastering then and could be achieved with a regular CD as well, or it is in your head only. There is no alternative explanation.

It's not impossible that it's cognitive bias on my part, if so, it's subconscious, as I did confuse the discs and ended up thinking I'd fooled myself, before realising that I'd just got the discs mixed up...

...but social phycologist Daniel Gilbert ran a study among people with no short-term memory ("synthetic happiness"detailed herein) that would seem to suggest that the subconscious can keep track of such things without conscious awareness, so...yes, it's possible it was cognitive bias; however...I don't believe it was.

 

[Rango]

https://cdn2.imagearchive.com/quadr...bility-of-a-CD-Standard-v-High-Resolution.pdf

@stoopid

Okay, so...let me know if I've got this right...or not...up to you.

I've been re-reading it and it seems in relation to the central question of this thread; the article is relevant in terms of the bit-rate?

The difference in bit-rate/data-transfer-rate between a file read from a CD via a laser and a file read from a lossless digital source (assuming there is (for sake of argument) a difference, albeit very small) is negligible in terms of the noise floor of the experiment detailed in this paper...

...which would suggest that even if there is a difference in data-read speed or completeness of signal when using a laser, it's indeterminable in practical terms; or in other words: no one can realistically hear a difference.

That's it, right? Have I got it?

Edit: ...okay...now I want validation. Did I get it right?

 

[DuncanS]

I'm an Electronic Eng/Physicist and I'd agree with "...which would suggest that even if there is a difference in data-read speed or completeness of signal when using a laser, it's indeterminable in practical terms; or in other words: no one can realistically hear a difference.".

If you can't measure it, you can't improve on it.

 

[splinter]

I don't believe it was.

That is your right to do, but then please don't ask us about lasers hitting surfaces and bits coming out of it, because that has nothing to do with belief, and we cannot argue for or against any beliefs.

difference in bit-rate/data-transfer-rate between a file read from a CD via a laser and a file read from a lossless digital source

You are making things up here. There is no difference in bitrate which is introduced by the laser. The bitrate is determined by the digital data. Whether you read it via laser from optical storage or magnetically from a hard disc or electrically from solid state storage makes no (NO!!!) difference. The data is the same. There is no noise being introduced by the reading of the data. Noise can be introduced in the analog-to-digital (ADC) or digital-to-analog conversion (DAC), which happens before writing to or after reading from the data store respectively.

 

[jimfisheye]

But you don't seem to want to address it; you seem to just want to talk about DAC's. My question, to boil it down to it's most basic, is whether a standard CD laser is a weak link in the system and whether eliminating it in favour of a lossless digital reproduction might produce a higher quality output.

Maybe if we reframe it...how about this: why should I believe a random person posting anonymously to a forum rather than trusting the manufacturer's claims?

You've offered me an argument from authority, which basically boils down to "just trust me". Why should I believe either of you?

Not sure what different words to try to use. You either successfully read a digital dataset or not. There's no 3rd state. I'm not sure if you are intentionally disagreeing that digital audio storage is a sequence of ones and zeros. Yeah, I thought that was on the face of it... Anyone got a link for the original documents on pcm audio with 16 bit samples at 44.1k samples per second?

I'm offering something you CAN talk subjectively about. DAC quality. Reading a sequence of ones and zeros is not subjective. You're going to have to explain how you think it is.

What's the quest here? Chasing down possibly clearer sounding copies of a commercial release? Or exposing perceived industry shenanigans?

Poor mastering and what appear to be novelty masters that are strikingly lo-fi are a thing. Even though a final master should be that and just cloned. There's all kinds of weirdness with this and collecting for cleanest copy has never been more of a quest! So there's that. Makes you constantly question why and how some copies got released or if they're even official.

No conspiracies in straight digital audio though. Read the data from your favorite storage medium and put it to your favorite DACs.

A CD player will play from an undamaged disk absolutely 100% perfectly. It will be the recording put to the disc for good bad or in between. The DAC you choose to pipe that digital data to is after the fact.

 

[jimfisheye]

https://cdn2.imagearchive.com/quadr...bility-of-a-CD-Standard-v-High-Resolution.pdf

@stoopid

Okay, so...let me know if I've got this right...or not...up to you.

I've been re-reading it and it seems in relation to the central question of this thread; the article is relevant in terms of the bit-rate?

The difference in bit-rate/data-transfer-rate between a file read from a CD via a laser and a file read from a lossless digital source (assuming there is (for sake of argument) a difference, albeit very small) is negligible in terms of the noise floor of the experiment detailed in this paper...

...which would suggest that even if there is a difference in data-read speed or completeness of signal when using a laser, it's indeterminable in practical terms; or in other words: no one can realistically hear a difference.

That's it, right? Have I got it?

Edit: ...okay...now I want validation. Did I get it right?

We're not listening to the data reading utility. We're listening to the already read data fed through a DAC. The data transfer part - slow/fast lasers and all - either happens successfully or not. If the system is too slow to keep up with playback, you get dropouts or the sounds of error correction trying to fill dropouts. Because the transfer failed!

That's not a sound quality study. Damn thing is broken!

 

[jimfisheye]

Well, this was fun! You're searching for some magic to find. I do understand! But I'm out. Good luck!

(Still telling you it's differently mastered editions to chase though.)

 

[Rango]

Well, this was fun! You're searching for some magic to find. I do understand! But I'm out. Good luck!

(Still telling you it's differently mastered editions to chase though.)

Not really...I didn't think this was fun at all, but thanks for the advice re. trying different masters and good luck to you.

My take away from this thread:

The consensus of accepted thinking seems to suggest there'd be no benefit in audio quality from ripping files from a disc; if you want an uplift in audio quality you could try upgrading to a receiver with a better DAC or upgrading your speakers.

Thanks everyone!