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Topic: PCM, DSD - Trying to get my head round some basics (Read 42112 times) previous topic - next topic
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Re: PCM, DSD - Trying to get my head round some basics

Reply #25
Recently I found out that Reed-Solomon is only effective if the disc is tracking properly, and mistracking could easily have been the reason for the difference in sound.
Hogwash.

Why do CD ripping programs have authentication databases if they get it right every time?

Obviously, they don't get it right all the time, and nobody with a brain expects them to. ;-)

However, if you get fairly consistent AccuRIP errors, that's nature's way of telling you that you may need to clean up your act. This is often as simple as physically cleaning the CD.


Re: PCM, DSD - Trying to get my head round some basics

Reply #26
Recently I found out that Reed-Solomon is only effective if the disc is tracking properly, and mistracking could easily have been the reason for the difference in sound.
Hogwash.

Why do CD ripping programs have authentication databases if they get it right every time?
How does that defend the position that a CD-R will provide better quality audio than the original disc from which it was sourced, catastrophic failures, not withstanding?

Or are you only talking about completely uninteresting trivial cases?

I think Mr Krueger's post gives an explanation better than I ever could.

Consider yourself countered, and a little bit rude. ;)

Re: PCM, DSD - Trying to get my head round some basics

Reply #27
My cd-r sounds better because it can be played back without skips and dropouts doesn't exactly rise to a level of being worthy of discussion, not that Barry Diament's bits are not bits nonsense is worthy, either.

My bad assuming you were naively defending the latter.  Based on the direction this topic was heading (acceptance of arguments coming from the Camp of Audiophile Woo), I hope you can understand why I jumped to this conclusion.  I had no idea I was being countered in a game of tiddlywinks.  You win, yay!

Re: PCM, DSD - Trying to get my head round some basics

Reply #28
That's how I thought it should work. Any input is split into whatever resolution you want (16/24/32).
The folks propagating "extra bits = greater dynamic range" as the ONLY reason for greater bit depth are wrong.

A dB is a logarithmic representation of a ratio. If dB is used with a suffix (for instance dB SPL), it is telling you the ratio relative to a predefined value specified by the suffix.

Increasing the bit depth increases the ratio between the largest and smallest value that can be represented by a factor 2x per bit (= ~6dB/bit).

The important thing to note is that if the smallest values that can be represented in a digital audio format are buried under noise in the listening environment or other factors or below you threshold of hearing when played back at a given listening level, then in the real world increasing bit depth doesn't really do anything. IOW increasing bit depth is only useful if it's the thing that is actually limiting resolution in the real world.

Re: PCM, DSD - Trying to get my head round some basics

Reply #29
The important thing to note is that if the smallest values that can be represented in a digital audio format are buried under noise in the listening environment or other factors or below you threshold of hearing when played back at a given listening level, then in the real world increasing bit depth doesn't really do anything. IOW increasing bit depth is only useful if it's the thing that is actually limiting resolution in the real world.
Noise already present in the content is one of those "other factors" which can be just as significant as the noise present in the listening environment.

Re: PCM, DSD - Trying to get my head round some basics

Reply #30
My cd-r sounds better because it can be played back without skips and dropouts doesn't exactly rise to a level of being worthy of discussion, not that Barry Diament's bits are not bits nonsense is worthy, either.

My bad assuming you were naively defending the latter.  Based on the direction this topic was heading (acceptance of arguments coming from the Camp of Audiophile Woo), I hope you can understand why I jumped to this conclusion.  I had no idea I was being countered in a game of tiddlywinks.  You win, yay!

Without starting afresh, I am not talking about skips and dropouts. Does the error correction not attempt to 'fill in' the gaps it can't read? Or am I thinking of another technology? It all becomes a blur after a while...
And I don't know why you keep thinking I'm pro-DSD when I'm trying to insist that I'm not taking sides!

Re: PCM, DSD - Trying to get my head round some basics

Reply #31
It's quite a stretch to claim audible differences in a situation where tracking problems have made it too difficult to provide data without interpolation, yet not so difficult for there to be skips and dropouts.  If these aren't just speculative anecdotal musings on your part, I'd love to see some evidence which conforms to the standard you agreed to follow when registering here.

There are proponents of both sides.
I like to try to gather information so I can make an informed decision, instead of blindly following one herd or the other - and understanding how these things work hopefully goes a long way to cut through the misinformation.

From the few samples I've downloaded so far, I can understand where the two camps come from, but I'm not sure the difference is worth fighting over.
In the case of taking sides, again, I'll point to the standard and its logical conclusion: all things should be assumed to sound the same unless it can be demonstrated otherwise.  Lending credibility to a side that has failed to fulfill the necessary burden of proof required by a science-based community is often taken as an affront.  This has been exacerbated thanks to a society that is increasingly rejecting science and the scientific method so belligerently.

Re: PCM, DSD - Trying to get my head round some basics

Reply #32
It's quite a stretch to claim audible differences in a situation where tracking problems have made it too difficult to provide data without interpolation, yet not so difficult for there to be skips and dropouts.  If these aren't just speculative anecdotal musings on your part, I'd love to see some evidence which conforms to the standard you agreed to follow when registering here.

There are proponents of both sides.
I like to try to gather information so I can make an informed decision, instead of blindly following one herd or the other - and understanding how these things work hopefully goes a long way to cut through the misinformation.

From the few samples I've downloaded so far, I can understand where the two camps come from, but I'm not sure the difference is worth fighting over.

In the case of taking sides, again, I'll point to the standard and its logical conclusion: all things should be assumed to sound the same unless it can be demonstrated otherwise.

As it was years ago, as I stipulated, we'll have to consider it an anecdote. Of course the intention of my mentioning it was supposed to be "in passing" and related to the strict black-and-white types that are always right, even though they haven't tested something for themselves. I agree with earlier sentiments that you can't argue against ABX if you're not willing to try it. It's the same principle.

Probably a moot point now anyway as manufacturing qualities seem to have improved no end since the old days...

Re: PCM, DSD - Trying to get my head round some basics

Reply #33
As it was years ago, as I stipulated, we'll have to consider it an anecdote.
...and as such I'm not buying it. ;)

Quote
Of course the intention of my mentioning it was supposed to be "in passing" and related to the strict black-and-white types that are always right, even though they haven't tested something for themselves. I agree with earlier sentiments that you can't argue against ABX if you're not willing to try it. It's the same principle.
Agreed.

Re: PCM, DSD - Trying to get my head round some basics

Reply #34
Without starting afresh, I am not talking about skips and dropouts. Does the error correction not attempt to 'fill in' the gaps it can't read? Or am I thinking of another technology? It all becomes a blur after a while...
In ripping about 2000 CDs I only had a handful that got any non-correctly corrected errors on first read at high speed.  Error handling on music CDs isn't great, but it's pretty good.  Some older CD transports did extrapolate or zero fill on significant enough errors and that could cause audible artifacts, but these errors are quite rare for most undamaged CDs.

Re: PCM, DSD - Trying to get my head round some basics

Reply #35
...and as such I'm not buying it. ;)

We are all who we are because of our life experiences. It wouldn't do to have us all the same now, would it?

Re: PCM, DSD - Trying to get my head round some basics

Reply #36
Of course not, but as human beings we are all prone to the same imperfections that lead us to draw erroneous conclusions, including how we interpret sound.  There are methods to get around this and these methods are required when one wants to posit claims about differences in sound quality.

Re: PCM, DSD - Trying to get my head round some basics

Reply #37
Dynamic range doubles when you add one more bit because you now have twice as many values you can produce.

Pcm spaces values uniformly in amplitude such that all levels are equally encoded. There are formats that space them non-uniformly, mostly as a means of lossy compression.

Re: PCM, DSD - Trying to get my head round some basics

Reply #38
All by yourself, as relatively easy as it really is, most people resist doing proper listening tests. I just got called a bunch of dirty names for politely pointing that out on another thread. But know it or not, you signed up to agree to that when you registered here. Please see TOS 8.

I didn't realise that I'd taken sides. I thought I'd deliberately been libertarian about the whole thing; not offending anyone or poking any cages by sitting on the fence. Now I'm being chastised for it?

[...]

Because of my own experiences, I don't try to tell anyone which side of the fence to sit on, that's up to them. I am happy for anyone to believe what they like until science changes its mind and proves otherwise.

It may not have been your intention, but proclaiming there are 2 sides and implying they're equivalent when the science is well established is a well known and tired cliche of science deniers. We see it regarding global warming, medicine, biology (evolution especially), and yes, even audio. It's the false equivalence fallacy.

Re: PCM, DSD - Trying to get my head round some basics

Reply #39
Ah yes, the stealth woo-woo pusher masquerading as an victimized oh-so-innocent answer seeker. Definitely never happened around these parts.

Re: PCM, DSD - Trying to get my head round some basics

Reply #40
yeah, I mean, I wasn't accusing him of it, but sometimes it's just indistinguishable from past experiences.

Re: PCM, DSD - Trying to get my head round some basics

Reply #41
All by yourself, as relatively easy as it really is, most people resist doing proper listening tests. I just got called a bunch of dirty names for politely pointing that out on another thread. But know it or not, you signed up to agree to that when you registered here. Please see TOS 8.

I didn't realise that I'd taken sides. I thought I'd deliberately been libertarian about the whole thing; not offending anyone or poking any cages by sitting on the fence. Now I'm being chastised for it?

[...]

Because of my own experiences, I don't try to tell anyone which side of the fence to sit on, that's up to them. I am happy for anyone to believe what they like until science changes its mind and proves otherwise.

It may not have been your intention, but proclaiming there are 2 sides and implying they're equivalent when the science is well established is a well known and tired cliche of science deniers. We see it regarding global warming, medicine, biology (evolution especially), and yes, even audio. It's the false equivalence fallacy.


Guys!
I've obviously got off on a bad start here.
It appears a glib remark has been allowed to run riot and get completely out of hand.

My apologies to Arnold K, who I now realise was trying to steer me in the direction required by the forum members, which I wrongly took as an attack at the time.
I am surprised at the vehemence on here though to anyone that doesn't hold the same 100% view as 'the gang' - how can that lead to interesting discussions? I haven't tried to force an opinion on anyone, in fact I deliberately tried not to.

I've had my appendix out. Oh wait! I can't prove it to you, therefore it didn't happen. Maybe the surgeon didn't really take it out, and I'm the victim of a conspiracy theory that I'm attempting to pass on.

No bad intended! Lighten up, guys!

Re: PCM, DSD - Trying to get my head round some basics

Reply #42
Ah yes, the stealth woo-woo pusher masquerading as an victimized oh-so-innocent answer seeker. Definitely never happened around these parts.

You guys are paranoid!

Re: PCM, DSD - Trying to get my head round some basics

Reply #43
At risk of getting my head bitten off again, here's another question that might appeal more to your reasoning:

Is there any Windows software (preferably free, or a trial version) where I can load a PCM and a DSD track simultaneously and subtract one from the other to display any difference (or NO difference!) between the two?

Re: PCM, DSD - Trying to get my head round some basics

Reply #44

Without starting afresh, I am not talking about skips and dropouts.

You could be talking about skips and dropouts  without knowing it.  Between the decades of development of methods for filling in gaps that can't be read and the ability of the human ear to accept them without notice, what you hear is not necessarily what you got.

Furthermore, what else could it be?  You hear this over and over again, and it, is true: Digital data either is perfectly correct or it isn't data at all. Basically the only fault that can intrude on the playback of optical disks is some kind of data loss. The audio part of the player can't and won't change timbre, pace or timing audibly  due to any probable fault.

Quote
Does the error correction not attempt to 'fill in' the gaps it can't read?

Yes.  The fill comes from the fact that the data is recorded redundantly. If a little bit of it goes missing, there is another copy some place else to fill it in with. The results are perfect recovery. If the loss is too large to cover this way, then typically it is replaced with a carefully executed mute, which if short and infrequent enough will slip by your ears unnoticed.

Quote
Or am I thinking of another technology? It all becomes a blur after a while...

Quote
And I don't know why you keep thinking I'm pro-DSD when I'm trying to insist that I'm not taking sides!

Not taking sides implies that DSD has equal merits with PCM which is false on practical grounds. Yes, you can get very  good sound either way, but the DSD route involves using a ton more data to do the same basic thing.

There's a reason why there was no such thing as workable SACD or DSD until there was a DVD disk base, with its very much larger data capacity and data rate features to waste time and money with.

Think of PCM as round earth, and DSD as flat earth. If there was a discussion of those issues, would you have a hard time taking sides?  If one is sufficiently informed about these things, that is how it would look.

Re: PCM, DSD - Trying to get my head round some basics

Reply #45
At risk of getting my head bitten off again, here's another question that might appeal more to your reasoning:

Is there any Windows software (preferably free, or a trial version) where I can load a PCM and a DSD track simultaneously and subtract one from the other to display any difference (or NO difference!) between the two?
You have to convert the DSD to PCM with a low pass filter first.  You will have the inevitable problem of finding the best alignment before subtracting.  Also if you download two files you don't know the provenance of the two files.

The short version is that the reconstruction filter for the PCM and the low pass output filter for the DSD drive most of the differences you'd see.  If the PCM is a high enough sample rate the differences will be negligible.

More details: if you take a high rate test tone PCM file (say >= 2.8224MHz), band limit it to less than 1/2 of the PCM output frequency for the PCM test tone, convert the original high rate PCM to DSD, run the DSD output filter on that to get back to high rate PCM, align the outputs with the input and subtract each output from the input (at the original high rate), then:  for PCM outputs that are lower sample rate than twice the DSD output filer cutoff you'll see more difference between them and the original test tone than between the DSD and the original test tone.  Conversely if your output sample rate is more than twice the DSD output filter cutoff you'll see a bigger difference between the DSD output and the test tone.  All of these differences are more affected by the implementation of the reconstruction filter for the PCM and the DSD output low pass filter than by whether they were ever DSD or high rate PCM.

There will also be some low level noise (below -120dBFS) in the DSD output over the audio band (say up to 30 or 40kHz) and then some rising ultrasonic noise up to the DSD output filter cutoff.  That noise will never exceed -40dBFS for SACDs and for higher rate DSD can be more negligible.

Re: PCM, DSD - Trying to get my head round some basics

Reply #46
Think of PCM as round earth, and DSD as flat earth. If there was a discussion of those issues, would you have a hard time taking sides?  If one is sufficiently informed about these things, that is how it would look.

That's exactly what I'm trying to do: inform myself about the technology so I can work it out for myself!

Re: PCM, DSD - Trying to get my head round some basics

Reply #47
At risk of getting my head bitten off again, here's another question that might appeal more to your reasoning:

Is there any Windows software (preferably free, or a trial version) where I can load a PCM and a DSD track simultaneously and subtract one from the other to display any difference (or NO difference!) between the two?

I can save you some work. 

If one held everything else constant, that is made them the same except for the format,  the PCM and DSD audio would be identically the same. Subtract them and you get a vanishing result.

But, in just about  every commercial case everything was not held the same, so there will almost  always be some difference that actually has nothing to do with comparing DSD to PCM. For example, commercial recordings  of music that was previously released in PCM are typically remastered. So they are different, but not because one is DSD and the other is PCM.  They are not quite the same recording.

Re: PCM, DSD - Trying to get my head round some basics

Reply #48
That's exactly what I'm trying to do: inform myself about the technology so I can work it out for myself!
I'm not trying to be flippant here, but if you want to work it out for yourself from fundamentals you'll need to truly understand sampling theory, noise shaping and sigma delta modulation.  Most people who get thru an undergraduate degree in the sciences or math still apparently don't know enough (or can't apply the theory to practice enough) to understand the technical nuances.

As other's have said, the details of practical implementations, mastering, etc. swamp the technical differences.