Thread: Should SA-CD.net take Blu-Ray Audio on board?

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Post by jackan August 20, 2014 (341 of 352)
tailspn said:

AmonRa's comment that "Just the method is different and in practice DAC is needed to convert it back to analog signal just as with PCM. If it was analog, no filtering etc would be needed" is the key to understanding why DSD is an analog format. No Digital to Analog Converter in the PCM sense of converting a string of digital binary word expressed amplitude values into an analog waveform is needed to recover the audio signal. Just a simple resistor and capacitor network (the integrator) is all that's required. As I referenced earlier, it's the actual signal recovery stage of the Ted Smith PS Audio Direct Stream multi format DAC, as well as other minimalist DSD only "DACs".

As shown, and linked earlier, while the modulator producing DSD is a combination of both analog, and digital logic elements, it produces a waveform per channel that contains the original signal expressed as the density of equal amplitude pulses on a continuous time line. There's no quantified digital binary values involved, or present.

I honestly can't tell if you are serious, actually believe what you are writing, and the stupidest person in the room on this topic, or trolling.

This circuit is far from simple, and is a Huge disservice to Ted Smith to describe it as so. And just because it has capacitors in it, does not make in an analog circuit. Digital circuits use capacitors too.

And filtering does not mean that this is a simple crossover circuit, as you might be used to seeing in the analog world.

He has made his own DAC. Digital to Analog Converter.
DSD is not in any way analog. Until it is converted to analog. By the converter.

Post by jackan August 20, 2014 (342 of 352)
tailspn said:

The concept of "Filter" is an effect of the resistor capacitor network, not its mathematical purpose. Its Integrator function role is to reverse the process of performing the modulation of a digital pulse train by the audio signal (a mathematical derivative function).

All of this technical discussion is only in service of the most important point: DSD is currently the highest accuracy and least invasive method of archiving and transmitting an analog audio signal. When, and if the industry develops production tools in PDM, it will completely displace PCM (the wax cylinder of digital format technology). At least today we have a range of recordings available that range between completely native DSD, through those that are mostly PCM. That's progress in my book.

Here is what is most discouraging to me.
This Place, SA-CD.net, is the best place in the world to discuss SA-CD.
In the world. This is as good as it gets.
And we have no Neal Tyson Degrasse, or Tom Danley, or Svetlomir Alexandrov to weigh in here, and explain the wonders of what we have. The most perfect form of music capture, storage, and playback, that we (human race) have been able to come up with yet. These people, if they existed (I think they do, I have seen some excellent posts from the archives, from before I started frequenting this place), have become bored, and left.

It's as if we had some kind of bizzaro debate, and we gave equal time to Neal Tyson Degrasse and Donald Trump. Why would we even do that in the first place? There are no two sides to this, there should be just the teacher, the truth.
Then, the moderator, and Neal got so bored, they went home. And all we are left with is Donald Trump, and Joe the Plumber. How the heck did Joe the Plumber even get a platform here, let alone, Donald Trump?

So now we have no reasonable discussion on SA-CD.
To the point that the very premise, (D), is being misconstrued.
We have no Neil to calmly explain that this is wrong, and how to get someone's mind around what is here.

We seem to even have no moderator, to put a stop to the madness and misinformation. We have devolved to Lowest Common Denominator.

So instead of having a wonderful wealth of knowledge. We have well meaning fan boys, with absolutely no idea of even the premise of what is at our fingertips.

And this is what will be the death of SA-CD.

Post by jackan August 20, 2014 (343 of 352)
To top it off, the person with the best idea of what is going on, is a non-believer. He knows more about the single bit process than anyone here, seemingly. Yet he can't hear the difference, or just goes on something that he has read as his reference.

So not only is he the most informed person on the process, but he is a denier of what it can accomplish. And this is the best we can do?

In the whole world of SA-CD?

Post by AmonRa August 20, 2014 (344 of 352)
Euell Neverno said:

So, that's your story and you're sticking with it. AmonRa?

By cleverly including PLAYERS in is argument I have to say Rammie is half right, but also half wrong.

Players certainly can sound different, as they include the DAC and the analog output stages.

Transports, by definition, just read the digital data from the disk and can not have any sound differences, as NO SOUND IS INVOLVED at this stage. There are ten, hundred times more "transports" included in everyday computers/laptops than in audio equipment, and in computers bit perfection is even more important than in audio, but still we see no $20000 CD-ROM and DVD-ROM readers and writers being offered to computer geeks to make the laptop CD/DVD-ROM readout more "high-res" and transparent. $30 "transports" are perfectly good. You should all ask yourself "why?". Or actually to try to finally understand the quantum difference between LP and CD/SACD.

Post by jackan August 20, 2014 (345 of 352)
AmonRa said:

By cleverly including PLAYERS in is argument I have to say Rammie is half right, but also half wrong.

Players certainly can sound different, as they include the DAC and the analog output stages.

Transports, by definition, just read the digital data from the disk and can not have any sound differences, as NO SOUND IS INVOLVED at this stage.

OOohhh! I will have to say that you are not half right, but 99% right.

And it is that last 1% that is the difference between RBCD, SC-CD, and Hi Res PCM.

That is the clocks.

Yes they are all 1s and 0s. But they have to be presented at EXACTLY the right time.

It took me over 35 years to get my head/ears around this.

I can finally hear what the "purists" who stuck with analog have against digital, after getting a grasp on DSD. And it took me years of contemplating SA-CD to get there.

Don't get me wrong. I would NEVER trade my CD player back for a turntable. The tradeoff's are way stacked in the CD's favor. But I can now get what the fervor has been about since 1983.

I have a friend/client who is a big 96/24 fan. And to him it is all about the spaces. The reverb trails. And I have to admit that this is a great reason to love the format. It's not the dynamics, or response, it's the spaces. They are so much better represented when the resolution is higher. And he can point out specific cases, where the hi res format sounds better. He is also an excellent system tuner. Setting up hi end studios in Burbank. He has showed me specific tunings that he has made, and how they differ from the original, just on one note of one instrument, and how that has made all the difference to him, in that one spot. Dude is into it.

But for me, the ultimate is the single bit. This format shines at dynamics. The very nature is not how much happened over the last time frame, but amount of time did it take for a change to happen. Of course this is all very meta, and faster than what we can hear. But the differences between the two can be very stark in the final analysis. This little difference on such a small level, can be the big difference in the final analysis.

It took me a long time to understand this. And I use my ears for a living.

I have one musician friend, who grasped this the first time I played it for her. She has a semi-crappy sound system that she usually plays through, which is fine for her. And she loves it when I do sound for her. Not just from the work end of it, but from the quality side. And I like her performances so much that I will go out of my way to do her sound for free. And she knows that she will sell more product when I am doing sound, just because the audience will, if even on a subconscious level, enjoy the performance better.

But when I showed her different formats, she was able to pick up on the nuances immediately. Almost unfair. And to her it was not even a big deal. She still listens to most of her music on MP3, she is just into the performance more than the format. And the cost is way more important to her than the overall quality.

Point is, that there is a difference. And that this difference is different things to different people. And that to most people the MP3 and earbuds are going to be as good as it gets.

Maybe you will never grasp the difference, and this is fine. But at least you understand so much more than most people. And enjoy what you are getting.

I do know that I have had to be groomed, trained, and taught to hear. I grew up with a musical mother, and siblings, and played music all of my adolescence, and through college. All the while listening to other things, and obsessing over music. And even with this, I had no idea what I was listening to, and had to be taught from scratch when I had to start mixing for a living. And I certainly have to go through a pile of chaf, to get to nuggets of musical genius. And the older and more jaded I get, the more it takes to turn me on, and spark my enthusiasm. But it is these experiences, the 1%, that make this pursuit worthwhile.

I hope that someday you will experience this 1% difference, and understand what 1 bit is about.

Post by off the grid August 26, 2014 (346 of 352)
Thanks, Tom!

Got it, I was missing the time domain element which was silly of me as we are dealing with 2.8 million bits per second. The "picket fence" analogy was by no means insulting as it provides a visual representation that hopefully will be as helpful to our fellow forum members as it has for me to help understand the analog nature of PDM/DSD.

For all on this thread that insist Tom is off his head in regards to his assertion that PDM/DSD is analog please refer back to the good old Laser Disc. The Laser Disc is a perfect example of PDM data ( referencing the video signal only ) being encoded as pits on a shiny optical disc (so it has to be digital, right?) but it was and is still analog even though it was being played back via an optical delivery and decoding system. PDM/DSD is analog encoded on an optical disc and decoded via an optical playback system just like the venerable Laser Disc. Just so I could confirm my recollection of the analog aspect of the Laser Disc I pulled up Wikipedia's Laser Disc entry and read the Design segment and the specific reference to PDM. For all of Wikipedia's warts I believe this entry is accurate.

Thanks again Tom as you really have been and continue to be a wonderful resource!

Post by Joseph Ponessa August 26, 2014 (347 of 352)
off the grid said:

The Laser Disc is a perfect example of PDM data ( referencing the video signal only ) being encoded as pits on a shiny optical disc (so it has to be digital, right?) but it was and is still analog even though it was being played back via an optical delivery and decoding system. PDM/DSD is analog encoded on an optical disc and decoded via an optical playback system just like the venerable Laser Disc. Just so I could confirm my recollection of the analog aspect of the Laser Disc I pulled up Wikipedia's Laser Disc entry and read the Design segment and the specific reference to PDM. For all of Wikipedia's warts I believe this entry is accurate.

Thank you for paying tribute to my favorite analog playback system, the Laser Disc. Of course, it later added a digital soundtrack, a high resolution PCM. Sometimes the digital tracks sounded better than the analog, but sometimes vice-versa, depending on how the mastering was done. On Bernstein's 1979 video of Beethoven's Ninth, for example, the analog tracks were superior to the digital, superior to the LP, superior to the CD, superior to the SACD. That laserdisc release was and remains the best presentation of that recording on any format.
I am not just prejudiced. I listened to about thirty laserdiscs in the last week, with great enjoyment. There are many great performances in excellent sound tastefully presented, with some titles that have never been released on any other format. On blu-ray video, by contrast, there are many excellent recordings of fair performances tastelessly presented, along with a number of titles that were never released on laserdisc. I need to have both formats.
Laserdisc was limited on the video side, incapable of anamorphic aspect ratio, and on the audio side, without capacity for multichannel high-resolution. But it could present analog stereo in pure analog without needing to use the physical contact of a stylus. It deserved more credit than it got. Its demise created a vacuum that was filled by SACD.

Post by off the grid August 27, 2014 (348 of 352)
You are welcome, Joseph!

The heady days of Laser Disc when the only other option was VHS were indeed a videophile and audiophile's dream. I still recall the BIG DEAL when 5.1 Dolby Digital and the associated AC-3 decoding was added near the end of Laser Disc's run.

In any case the Laser Disc based on PDM analog encoding and being an optical disc was a natural analogy to try to further substantiate Tom's assertions that DSD/PDM is analog even though it's delivery media as SACD discs or downloads would imply pure digital from front to back.

Tom I hope I am not barking up the wrong tree here and undermining your efforts?

Post by Fitzcaraldo215 August 27, 2014 (349 of 352)
off the grid said:

...

For all on this thread that insist Tom is off his head in regards to his assertion that PDM/DSD is analog please refer back to the good old Laser Disc. The Laser Disc is a perfect example of PDM data ( referencing the video signal only ) being encoded as pits on a shiny optical disc (so it has to be digital, right?) but it was and is still analog even though it was being played back via an optical delivery and decoding system. PDM/DSD is analog encoded on an optical disc and decoded via an optical playback system just like the venerable Laser Disc. Just so I could confirm my recollection of the analog aspect of the Laser Disc I pulled up Wikipedia's Laser Disc entry and read the Design segment and the specific reference to PDM. For all of Wikipedia's warts I believe this entry is accurate.

I also read the Wiki article on Laserdisk, but nowhere do I find a reference in it to Pulse Density Modulation(PDM). It says that the video signal is instead represented as Pulse WIDTH Modulation (PWM), which is a different animal entirely. That is used in audio primarily in power supplies and for signal internally in Class D amplifiers, so not relevant to DSD. The audio on Laserdisk is usually analog along with simultaneous PCM=Pulse Code Modulation tracks, also not relevant.

Note that all these contain the word "modulation" in their names. So, PDM is not alone in being a form of modulation, nor does that in itself make something analog or digital: there are many forms of analog modulation as there are of digital modulation.

Continuing with Wiki, this time under the Pulse Density Modulation article, it is defined as "a modulation technique to represent analog signal with digital data". That article also makes clear that PDM is what DSD is, and that the one values represent a one step rising signal, and the zeros represent a one step falling signal, one-bit sample by sample. The sample values therefore represent the single-step deltas to the signal, unlike PCM where the samples are multi-bit words each defining the actual signal level or sigma at that sample. The greater sample size in bits for PCM generally necessitates a much lower sampling rate to work within similar storage or bandwidth limits as PDM, which allows much higher sample rates of one bit samples.

With DSD/PDM, it is possible to cumulatively add up the deltas with a simple transform to the sample values: sample value of 1=+1 arithmetically, sample value of 0=-1 arithmetically. This summation can be done on the fly sample by sample from the beginning of an SACD track, say, to get the instantaneous signal level as a digital, arithmetic number, if that is something you need or want to do.

So, again, we have a definition of DSD/PDM as digital, composed of discrete one-bit samples with a value of 0 or 1. That's not analog any more than PCM is, although the two are different in many other ways, except both are digital modulation schemes. And, by the way, when someone mentions a picket fence, I see nothing but digital. Others might see analog, but I do not see how.

I have not looked everywhere, but I dare say anyone would be hard pressed to come up with a credible, expert definition of DSD or PDM that considers them analog. Also, the process of conversion of DSD/PDM via D to A, as it is usually called, does not make this representation analog. The instant you start to convert the digital signal to analog, what you are working with is no longer in DSD/PDM representation in the digital domain.

Post by off the grid August 27, 2014 (350 of 352)
Hi Fitz,

Yup you are correct a classic case of being over worked and seeing what I hoped to see, not what was present. I had to go back and re-read the Wiki and scratch my head as to how I construed PWM as PDM, big duh! I will now go back to listening to and enjoying my SACD's...

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