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Topic: PCM, DSD - Trying to get my head round some basics (Read 43082 times) previous topic - next topic
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Re: PCM, DSD - Trying to get my head round some basics

Reply #50 –
Quote from: shakeshuck on
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?
teac hi-res editor

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

Reply #51 –
Quote from: shakeshuck on
Quote from: Palladium on
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!

The apparent paranoia comes from about 17 years experience with DSD advocates trying to pull the wool over our eyes.  That it was a scam to foist off highly restrictive IP protection and open up a new market for redundant, overpriced hardware was apparent to many of us immediately. 

The means by which the scam would be falsely granted improved sound quality by means of remastering was also obvious to many of us.

But, nevertheless better men than I (example: Meyers and Moran of AES Journal fame) have succumbed at least temporarily (for several years - almost a decade). 

The extent the scam was that as of about 2006, about half of all SACD (DSD) recordings were based on analog recordings whose dynamic range and bandwidth was actually inferior to plain vanilla PCM (e.g. CD), yet no golden eared reviewer that I know of has ever blown the whistle on this to this day. 

Techies did start blowing the whistle on this part of the scam  a few years later, but only a few noticed it. The whistle blowing was squirreled away in some dusty old AES Conference papers.

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

Reply #52 –
Quote from: Arnold B. Krueger on
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.
Almost, except that individual samples with errors that cannot be corrected are interpolated. This is what usually happens with light damage which does not cover the case when the laser can no longer track.

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

Reply #53 –
Quote from: greynol on
Quote from: Arnold B. Krueger on
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.
Almost, except that individual samples with errors that cannot be corrected are interpolated. This is what usually happens with light damage which does not cover the case when the laser can no longer track.

Yup, that, too. Slipped my mind.  The  modern times real world circumstances by which this happens escapes me.

While audiophiles seem to have focused their attention on sound quality and more particularly DAC and output buffer quality,  the technical battle that absorbed the most resources and provided the most audible benefits for say, the first decade of the CD was tracking performance.  Not being able to play the disc at all or not being able to play it without audible breaks resulted in a lot of product returns, and retailers take that pretty seriously.  Sound quality can be a judgement call, but not playing is pretty cut and dried.

Surprisingly, good examples of the original CDP 101 tracked pretty well, and even handled CD-Rs well enough. However many early samples had defective chips related to the tracking servos, that failed pretty early in life. The shared mono DAC with 1/2 sample delay between the channels was audible if you had a center channel, and response roll-offs above 13 KHz due to the analog filters could be heard, given the right program material.

The first generation DACs generally had barely audible failings, and the better quality second generation DACs were essentially audibly perfect. That left things like cost and size as the areas of actual real progress. The perfection of delta-sigma technology which was pretty well done by the mid-90s took care of that.

An exception was high end CD players which were separated into two boxes, one with the transport and one with the DAC. This was a lot easier to sell to audiophiles than to justify technically and it did lead to audible problems with interfacing the two boxes.  There is a well known right way to do this, but a lot of the high end products whose circuits I reviewed cheaped-off and did it wrong.

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

Reply #54 –
Quote from: nastea on
Quote from: shakeshuck on
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?
teac hi-res editor

I downloaded it and tested it and it ran without serious problems in Windows 10/64.  It does seem to have some subtle issues. I round tripped the RMAA6 24/96 test file through DSD 2.8 land and it came back changed a little. There were  some subtle 0.2 dB frequcny response roll offs, and visible transient distortion of the raw test signal.  Probably worth listening to.

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

Reply #55 –
Quote from: shakeshuck on
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.
AJ might not agree, but I do believe you honestly thought you saw a UFO.  But since you can't provide objective proof then it isn't worthy of discussion.

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

Reply #56 –
Well, to be fair, I believe he (Rich?) honestly thought he heard this also:
Quote from: shakeshuck on
I once (years ago) brought up the subject of CD burning, and that in an experiment I had done the newly burned CD sounded better than the stamped original. I didn't know why, it just did as far as I was concerned.
Much like my 6yr old nephew heard Santa last Christmas.
I just believe there may be alternate explanations for what was "heard". Honestly. Of course, one of those could be ABX'd per forum standards.
And now back to fishing...
Loudspeaker manufacturer

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

Reply #57 –
The latest "Rich" sock was banned a few days ago.

This would be a new record from him for rising from the dead, but yeah, "both sides have valid points" is an effective dog whistle around here, ignoring the implied claim that a difference was heard, even if he wasn't sure it was "worth fighting over."

Quote from: Arnold B. Krueger on
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.
;)

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

Reply #58 –
Quote from: greynol on
Quote from: shakeshuck on
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.
AJ might not agree, but I do believe you honestly thought you saw a UFO.  But since you can't provide objective proof then it isn't worthy of discussion.

Fair cop.

It also says: "by being polite and encouraging him to join in with how we do things here."
and "the manner in which you coax these people into doing things the right way is very important"

Mmmmh.
Or maybe I was just being a little OCD sensitive?

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

Reply #59 –
Quote from: greynol on
The latest "Rich" sock was banned a few days ago.

This would be a new record from him for rising from the dead, but yeah, "both sides have valid points" is an effective dog whistle around here, ignoring the implied claim that a difference was heard, even if he wasn't sure it was "worth fighting over."

Quote from: Arnold B. Krueger on
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.
;)

And I told you I HAD tried ABX testing, the software just made it too easy for a valid comparison.

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

Reply #61 –
Quote from: shakeshuck on
Quote from: andy o on

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!
You are not getting it. You think you're just being jokey, but what you're saying (again) is not different to what trolls and science deniers say for real.

Saying that you're taking no position or that you're somehow in the middle implies there are 2 positions that are equivalent in the first place. You may not be taking any of your 2 imagined positions, but you are taking a position. A better way to approach this if you are a newb to the subject is to just ask what does the science say up to now.

Getting out an appendix is not an extraordinary thing that goes against previous established science. If you said you were alien-abducted or were seeing ghosts, or that you hear DSD and PCM difference, then that's something that would require evidence from you.

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

Reply #62 –
Quote from: shakeshuck on
It also says: "by being polite and encouraging him to join in with how we do things here."
and "the manner in which you coax these people into doing things the right way is very important"
That's what David said.  Neither the terms nor their descriptions say either.  Not that we shouldn't operate in this manner.

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

Reply #65 –
Quote from: shakeshuck on
[And I told you I HAD tried ABX testing, the software just made it too easy for a valid comparison.


The way to solve this problem was to do as  much processing as you could outside of the listening test comparison.

AFAIK the volume leveling feature you used involved steady state gain changes, so it really was just a standard question of level matching.

The way I level match is to do the following in preparation for the listening test:

(1) Mark out comparable timed points on the music. This is very much facilitaed if time-synching is done first. Time synching is done by identifying a unique feature and adding or subtracting silence at the beginning of the files until the feature has the same timing in both files, within a millisecond or less.

(2) Measure the RMS or if no RMS calculation is available, the average value associated with the level of music between the two points in each piece of music.

(3) Adjust the level in one file or the other until the RMS values are the same +/- 0.05 dB or better.
 

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

Reply #66 –
Quote from: andy o on
Saying that you're taking no position or that you're somehow in the middle implies there are 2 positions that are equivalent in the first place. You may not be taking any of your 2 imagined positions, but you are taking a position. A better way to approach this if you are a newb to the subject is to just ask what does the science say up to now.

I obviously misread the tone of the forum when I first started posting.
I assumed there would be proponents of both PCM and DSD on here, happily comparing notes - so I made a comment aimed at not offending one way or the other.
Boy, was that a misguided thing to do. In trying NOT to offend, I seem to have achieved exactly the opposite.

As for joking, I'm trying to make light of a situation that is approaching the absurd.

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

Reply #68 –
Quote from: Arnold B. Krueger on
Quote from: shakeshuck on
[And I told you I HAD tried ABX testing, the software just made it too easy for a valid comparison.


The way to solve this problem was to do as  much processing as you could outside of the listening test comparison.

AFAIK the volume leveling feature you used involved steady state gain changes, so it really was just a standard question of level matching.

The way I level match is to do the following in preparation for the listening test:

(1) Mark out comparable timed points on the music. This is very much facilitaed if time-synching is done first. Time synching is done by identifying a unique feature and adding or subtracting silence at the beginning of the files until the feature has the same timing in both files, within a millisecond or less.

(2) Measure the RMS or if no RMS calculation is available, the average value associated with the level of music between the two points in each piece of music.

(3) Adjust the level in one file or the other until the RMS values are the same +/- 0.05 dB or better.

I tried manually adjusting the ReplayGain tags on the files to get them somewhere close, but it turns out that Foobar/ABX Comparator ignores the tags when doing a comparison. You can use auto ReplayGain, but that was what was not working for me.

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

Reply #69 –
Quote from: Arnold B. Krueger on
(2) Measure the RMS or if no RMS calculation is available, the average value associated with the level of music between the two points in each piece of music.
He should probably lowpass to no greater than the nyquist of the PCM samplerate first.

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

Reply #70 –
Quote from: Arnold B. Krueger on
(3) Adjust the level in one file or the other until the RMS values are the same +/- 0.05 dB or better.

If I'm still trying to use Foobar for the comparison, what software would you suggest I use to alter the file levels? Obviously it would have to be PCM based, as - if I read it correctly - I can't alter a DSD file easily.

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

Reply #71 –
Quote from: nastea on
Quote from: shakeshuck on
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?
teac hi-res editor

I have used this for converting between file types for testing, but I am not aware that it will allow me to subtract samples from each other in order to easily see any differences.

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

Reply #72 –
Quote from: greynol on
Test samples to allow others to reproduce your findings?

https://hydrogenaud.io/index.php/topic,3974.html

I appreciate you weren't on the ball when you made this statement, but I'm curious as to what this would achieve?
Let's say as an example that I could do multiple ABX tests and do relatively well consistently.
If others try the same test with the same samples and fail, does that then invalidate my findings?

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

Reply #73 –
Quote from: shakeshuck on
Quote from: greynol on
Test samples to allow others to reproduce your findings?

https://hydrogenaud.io/index.php/topic,3974.html

I appreciate you weren't on the ball when you made this statement, but I'm curious as to what this would achieve?
Let's say as an example that I could do multiple ABX tests and do relatively well consistently.
If others try the same test with the same samples and fail, does that then invalidate my findings?

If no one ever could? Yes, probably people would assume you got lucky or made a mistake.

Usually though the purpose of this is to sanity check someone else's results for obvious errors and then to let other people try and see how they do. Replication and review are the basis of all science and engineering.

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

Reply #74 –
Quote from: shakeshuck on
Quote from: nastea on
Quote from: shakeshuck on
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?
teac hi-res editor

I have used this for converting between file types for testing, but I am not aware that it will allow me to subtract samples from each other in order to easily see any differences.

You can't subtract audio in two different sampling rates because there are not the same number of samples. You must first convert them to a common sampling rate, time align them, and then subtract. Note that this process is often very complex for formats that are substantially different.