HydrogenAudio

CD-R and Audio Hardware => CD Hardware/Software => Topic started by: Livy on 2008-07-29 14:06:21

Title: SHM-CD Format: Hype or Hope?
Post by: Livy on 2008-07-29 14:06:21
There's been a lot of discussion over at SA-CD Net about SHM-CD's and whether the "clearer plastic" technology they use generates any actual improvement in sound quality.  Many people simply don't believe that would be possible.  Metallica's new album - Death Magnetic - is going to be released in Japan in SHM-CD format. 

I'm not very knowledgeable about this area - does anyone here know more or have opinions about SHM-CD?

Edit: I've read that mastering engineer Ted Jansen is going to working on this album - whether as mastering and recording engineer, I don't know.
Title: SHM-CD Format: Hype or Hope?
Post by: odyssey on 2008-07-29 14:12:14
I quickly found this rather amusing thread (http://www.stevehoffman.tv/forums/showthread.php?t=127465) elsewhere.

If it's a CD, then WHATEVER material it's made of, nothing but FUZZ! With EAC you can extract the actual content of a CD. A different plastic, gold layer or anything in that calibre would not change it!
Title: SHM-CD Format: Hype or Hope?
Post by: Rain on 2008-07-29 15:01:23
Does it matter? The album's going to be as loud as hell
Title: SHM-CD Format: Hype or Hope?
Post by: Fandango on 2008-07-29 17:07:23
I quickly found this rather amusing thread (http://www.stevehoffman.tv/forums/showthread.php?t=127465) elsewhere.

If it's a CD, then WHATEVER material it's made of, nothing but FUZZ!


Not a fuzz, but makes you fuzzy in the head! Just read this:

Quote
"Super High Material CD
SHM-CD series

Pursuing the new possibility of CD!
The liquid crystal panel material (high transparency) the high sound quality CD by the new material which is utilized appears (out of nowhere! that's far out, man!!
The first press limitation"

SHM-CD is pure dope, I think!

EDIT: Ok. Sorry for the rule #8 violation in this post. Of course, I must do some double blind ingestion/smoking tests with these new CDs first, but you must understand that the high expectations make me all jittery, so to speak.
Title: SHM-CD Format: Hype or Hope?
Post by: unfortunateson on 2008-07-29 18:43:58
bits are bits.
Title: SHM-CD Format: Hype or Hope?
Post by: giopiar on 2008-07-29 20:48:33
This is a semplification, but you could imagine an audio CD similar to a device containing digital informations, even if Red Book doesn't have block-accurate addressing.

Think about a wave file which you might put on an Hard drive, a CD, a solid state disk, etc: it is always the same file even if the media is different! A CD is not a vinyl disc. In vinyl audio is recorded in an analogic way, it means that "the better is built, the better it will sound", but the CD is totally different.

AFAIK I can imagine that using a better material could cause less jitter which occour, as I have already said, because the Red Book doesn't require block-accurate addressing, but I don't think nowadays jitter is a real issue...

essentially: IMO that's garbage... 
Title: SHM-CD Format: Hype or Hope?
Post by: .halverhahn on 2008-08-01 22:27:43
Digital data are media independent. Even you write the bits on a sheet of paper, it will stay the same as on CD/DVD/HD/FLOPPY/RAM/FLASH etc.
Title: SHM-CD Format: Hype or Hope?
Post by: Sebastian Mares on 2008-08-01 23:02:57
I once wrote an e-mail to Stereo or some other magazine I had a look at in the library. They had a comparison between PC CD burners and claimed that the sound of the CDs burnt by the Plextor Premium (Premium2 if I recall correctly) have a much clearer sound and blah. I asked them how on earth they can hear differences since all burners should write the same ones and zeros and if not, there must be something very bad going on with their hardware. Anyways, the answer was that it has something to do with how CD players interpolate when errors are spotted and that good writers produce less errors which leads to less interpolation attempts.
Title: SHM-CD Format: Hype or Hope?
Post by: Tahnru on 2008-08-01 23:23:19
I'm going to buy one of these, draw a green ring on the edge, freeze it with liquid nitrogen, and run it through my demagnetizer.

I'll have better bits than anyone. My ones will be more singular, my zeros will be truly nothing.  I will be the digital king.

What do you think ... too much?
Title: SHM-CD Format: Hype or Hope?
Post by: Sebastian Mares on 2008-08-01 23:55:38
What do you think ... too much?


It's all worthless if you don't use a highly priced digital audio cable like this (http://www.amazon.com/Denon-AKDL1-Dedicated-Link-Cable/dp/B000I1X6PM/ref=pd_bbs_sr_1?ie=UTF8&s=electronics&qid=1217631298&sr=8-1) or this (http://www.amazon.com/AudioQuest-class-optical-cable-TosLink/dp/B0006VPPPI/ref=pd_bbs_2?ie=UTF8&s=electronics&qid=1217631298&sr=8-2). And don't forget bi-wiring!
Title: SHM-CD Format: Hype or Hope?
Post by: Tahnru on 2008-08-02 00:17:30
Oh I know!  And you can't even make it from the wall to receiver without one of these! (http://www.dedicatedaudio.com/inc/sdetail/2409)

I forgot about bi-wiring ... I guess I'll have to sell my other kidney to pick up the second set.  Should I go with another of the same pair (http://www.4electronicwarehouse.com/products/monster/z4-reference.html?id=3716&utm_source=GoogleBase&utm_term=&utm_campaign=monster&utm_medium=comparison) as I currently have, or should I upgrade to something better (http://www.pearcable.com/sub_products_anjou_sc.htm)?
Title: SHM-CD Format: Hype or Hope?
Post by: me7 on 2008-08-02 01:36:46
...or should I upgrade to something better (http://www.pearcable.com/sub_products_anjou_sc.htm)?


HOLY SHIT!!! I'd love to meet the moron who invented this just to tell him how stupid he is.
Title: SHM-CD Format: Hype or Hope?
Post by: Egor on 2008-08-02 08:31:28
Bi-wiring/amping concept itself isn't a bad thing when used with reasonable priced cables. At least it *may* potentially improve something in amplification/reproduction process. (The previous posts sound like bi-wiring is for idiots who spend thousands on wires.)
Title: SHM-CD Format: Hype or Hope?
Post by: honestguv on 2008-08-02 12:00:44
...or should I upgrade to something better (http://www.pearcable.com/sub_products_anjou_sc.htm)?


HOLY SHIT!!! I'd love to meet the moron who invented this just to tell him how stupid he is.


Why is he stupid?

Selling a product where the cost of purchasing the item (or manufacturing in one or two cases) is a very small fraction of the retail price does not look stupid to me. Significant costs are going to be in the marketing and this needs to be effective for consumers of expensive audiophile cables. It does not matter much what those who are not consumers think of the marketing.

I would suggest that the consumers of expensive audiophile may well be described as stupid in most cases but I can see no reason to assume stupidity on the part of the suppliers.
Title: SHM-CD Format: Hype or Hope?
Post by: Silversight on 2008-08-02 16:34:15
Why is he stupid?

[...]

I would suggest that the consumers of expensive audiophile may well be described as stupid in most cases but I can see no reason to assume stupidity on the part of the suppliers.

The stupid one IMHO is that Positive Feedback Editor. His review (http://www.positive-feedback.com/Issue32/anjou.htm) is ridiculous!
Title: SHM-CD Format: Hype or Hope?
Post by: Fandango on 2008-08-02 18:13:48
The stupid one IMHO is that Positive Feedback Editor. His review (http://www.positive-feedback.com/Issue32/anjou.htm) is ridiculous!

This is still my favorite quote:

Quote
In extended listening sessions, I found the cables' greatest strength to be its PRAT. Simply put these are very danceable cables. Music playing through them results in the proverbial foot-tapping scene with the need or desire to get up and move. Great swing and pace  —these cables smack that right on the nose big time.



danceable bi-wiring with a great swing and pace:
(http://thebadplus.typepad.com/photos/uncategorized/2007/09/11/double_dutch.jpg)
Title: SHM-CD Format: Hype or Hope?
Post by: greynol on 2008-08-02 18:51:42
I would suggest that the consumers of expensive audiophile may well be described as stupid in most cases but I can see no reason to assume stupidity on the part of the suppliers.

...it's like saying Haliburton was stupid for making money off the war in Iraq.
Title: SHM-CD Format: Hype or Hope?
Post by: honestguv on 2008-08-02 21:06:35
The stupid one IMHO is that Positive Feedback Editor. His review (http://www.positive-feedback.com/Issue32/anjou.htm) is ridiculous!

Again I disagree. The editors of publications like Positive Feedback, Stereophile, 6Moons, and similar are earning a good income (I presume given the length of time they have been doing it) by promoting audiophile nonsense on behalf of the audiophile industry. This upbeat positive nonsense about audiophile hardware makes their publications attractive vehicles for advertising. Further down the food chain in the publications there are some indications that some of the writers believe some of the audiophile nonsense and a label of stupid may well be fair in this case.

If we assume that Dave Clark is not a total loony, why is he making ludicrously over the top statements about danceable cables that no non-audiophile could possibly accept as being true? If you read the reviews on other completely absurd audiophile components like clever clocks, resonating cups, and the like you will almost always see the same over the top statments. Why? If the authors were making an honest attempt to deceive the likes of you or I would they do this?


I would suggest that the consumers of expensive audiophile may well be described as stupid in most cases but I can see no reason to assume stupidity on the part of the suppliers.

...it's like saying Haliburton was stupid for making money off the war in Iraq.

Granted neither is stupid but I would not put war profiteering in the same category as helping to sell nonsense luxury products to stupid rich people many of whom are perfectly happy with their purchases.
Title: SHM-CD Format: Hype or Hope?
Post by: greynol on 2008-08-02 21:12:11
I can assure you that my hyperbole was intentional.
Title: SHM-CD Format: Hype or Hope?
Post by: honestguv on 2008-08-02 22:21:25
I can assure you that my hyperbole was intentional.

My mistake and my apologies. As an Englishman it is perhaps more embarrassing to miss this type of thing than for you colonials. Of course, I have an excuse...
Title: SHM-CD Format: Hype or Hope?
Post by: greynol on 2008-08-02 22:41:27
No apologies necessary.  I wouldn't expect you or anyone else to know my opinion on subject, but I think it's in line with the rest of the people here.  I don't feel sorry for fools who part with their money.  If it results in their dependents going without then I take issue with the matter.  More to the point, I'm not convinced this type of commerce is good for the world economy.  We know what happens to bubbles, especially when they get filled with hot air; and these guys have a lot of it to sell.
Title: SHM-CD Format: Hype or Hope?
Post by: Bodhi on 2008-08-02 23:09:37
A different plastic, gold layer or anything in that calibre would not change it!

It would just change the time life of your CD.
Title: SHM-CD Format: Hype or Hope?
Post by: insane_alien on 2008-08-03 01:47:23
SHM-CD = SHAM-CD

a bit for bit copy is the same nomatter what media it is off of. i could get  the data tatooed on my left buttock scan it in and it would still sound the same.

now, if they were offering something truely advantageous like an unscratchable disc orsomethng then it might be a good thing.
Title: SHM-CD Format: Hype or Hope?
Post by: Tahnru on 2008-08-05 22:21:00
I had wanted to post this to the thread, but I forgot until today.

The Audio Critic's "10 Biggest Lies in Audio" (http://www.theaudiocritic.com/downloads/article_1.pdf)
Title: SHM-CD Format: Hype or Hope?
Post by: Tahnru on 2008-08-06 06:30:57
Bi-wiring/amping concept itself isn't a bad thing when used with reasonable priced cables. At least it *may* potentially improve something in amplification/reproduction process. (The previous posts sound like bi-wiring is for idiots who spend thousands on wires.)


Bi-wiring by itself is different than bi-wiring/bi-amping, BTW.
Title: SHM-CD Format: Hype or Hope?
Post by: Axon on 2009-05-21 03:00:48
A couple (http://www.stevehoffman.tv/forums/showthread.php?t=181469) of incredibly (http://www.stevehoffman.tv/forums/showthread.php?t=158178) bizarre threads over at sh.tv has uncovered hard evidence (some contributed by yours truly) (http://www.stevehoffman.tv/forums/showthread.php?p=4414018#post4414018) that some SHM-CDs contain more clipping than their normal CD counterparts. On a LZ SHM-CD specifically:

Quote
Quite simply, the only difference between the SHM CD and the Marino master, as indicated by these samples, is an extra 0.6db of gain, and additional brickwall clipping.


There are also diverse examples provided of the SHM-CD digital content being exactly the same (or suspected to be the same from track peaks) as the normal CD counterparts. Even then, several individuals are adamant that SHM-CDs sound better than their normal counterparts (even with the ones with increasing clipping). There has been absolutely no evidence found of any SHM-CD having a higher quality digital master than its normal CD counterpart.

The manufacturing technology has not been shown to give no benefit under normal CD playback conditions. But if all you're going to do is rip it to your computer, there's provably no benefit to SHM-CD.
Title: SHM-CD Format: Hype or Hope?
Post by: WonderSlug on 2009-05-21 05:04:18
I'd rather they spend time on better manufacturing techniques that yield real results.

For example, a better plastic that doesn't scratch as easily, or better substrates that won't separate or tilt (warped disc) after a period of time.
Title: SHM-CD Format: Hype or Hope?
Post by: ShowsOn on 2009-05-21 05:28:45
I gave up on that thread around page 40.
Title: SHM-CD Format: Hype or Hope?
Post by: krabapple on 2009-05-21 17:25:21
A couple (http://www.stevehoffman.tv/forums/showthread.php?t=181469) of incredibly (http://www.stevehoffman.tv/forums/showthread.php?t=158178) bizarre threads over at sh.tv has uncovered hard evidence (some contributed by yours truly) (http://www.stevehoffman.tv/forums/showthread.php?p=4414018#post4414018) that some SHM-CDs contain more clipping than their normal CD counterparts. On a LZ SHM-CD specifically:Quite simply, the only difference between the SHM CD and the Marino master, as indicated by these samples, is an extra 0.6db of gain, and additional brickwall clipping.



You mean, the supposed virtues of the format are offset by the actual mastering?  Shocking.   

Quote
There are also diverse examples provided of the SHM-CD digital content being exactly the same (or suspected to be the same from track peaks) as the normal CD counterparts. Even then, several individuals are adamant that SHM-CDs sound better than their normal counterparts (even with the ones with increasing clipping). There has been absolutely no evidence found of any SHM-CD having a higher quality digital master than its normal CD counterpart.


Several individuals on Hoffman's forum are clueless jackasses as regards audio.
Title: SHM-CD Format: Hype or Hope?
Post by: ShowsOn on 2009-05-21 17:45:31
Several individuals on Hoffman's forum are clueless jackasses as regards audio.

The scary one was the mastering 'engineer' Barry Diament's contributions to the thread where he refused to accept that when the WAV comparator in Exact Audio Copy says two WAVs are identical, that that would mean they are exactly the same mastering. He kept on saying the only way to be sure is to null the files after ensuring that the first samples line up.

I guess it proves that you don't need a degree in audio engineering to be a mastering 'engineer'.
Title: SHM-CD Format: Hype or Hope?
Post by: Seeking_Lossless on 2009-05-21 17:46:39
Even on vinyl also that album still clip. It's impossible to get amazing sound of Death Magnetic in any format as the original master tape/or whatever also has been brickwalled to death.
Title: SHM-CD Format: Hype or Hope?
Post by: krabapple on 2009-05-21 18:14:44
Several individuals on Hoffman's forum are clueless jackasses as regards audio.

The scary one was the mastering 'engineer' Barry Diament's contributions to the thread where he refused to accept that when the WAV comparator in Exact Audio Copy says two WAVs are identical, that that would mean they are exactly the same mastering. He kept on saying the only way to be sure is to null the files after ensuring that the first samples line up.

I guess it proves that you don't need a degree in audio engineering to be a mastering 'engineer'.



IME Diament's a fountain of dubious 'information' and audiophoolery. And in the end he will *always* retreat to 'I hear it, and that's all that matters'.


And they worship him on SH.tv.


Btw, Diament makes available a 24/96 vs 16/44 comparison , that HA might be interested in .  Hosted here:


http://www.soundkeeperrecordings.com/format.htm (http://www.soundkeeperrecordings.com/format.htm)
Title: SHM-CD Format: Hype or Hope?
Post by: WonderSlug on 2009-05-21 18:50:27
Several individuals on Hoffman's forum are clueless jackasses as regards audio.

The scary one was the mastering 'engineer' Barry Diament's contributions to the thread where he refused to accept that when the WAV comparator in Exact Audio Copy says two WAVs are identical, that that would mean they are exactly the same mastering. He kept on saying the only way to be sure is to null the files after ensuring that the first samples line up.

I guess it proves that you don't need a degree in audio engineering to be a mastering 'engineer'.


Well, if he won't accept what EAC is telling him, maybe he'll accept what Windows tells him.

Compare the two WAV files by using Windows' "comp" command line executable.

Open up a Command Prompt and use:

comp first.wav second.wav



If comp returns a "Files Compare OK" then that means first.wav and second.wav are byte-for-byte exact duplicates.
Title: SHM-CD Format: Hype or Hope?
Post by: ShowsOn on 2009-05-22 14:08:39
IME Diament's a fountain of dubious 'information' and audiophoolery. And in the end he will *always* retreat to 'I hear it, and that's all that matters'.

Yeah, he is one of those people that argues that CDs made from exactly the same digital master can sound different simply because they were made in different pressing facilities, even if the discs contain identical data. This usually cues a pointless 'discussions' about jitter.

I can't imagine discussing SHM-CD with someone who believes identical bits can produce varying sound (in a properly functioning player) will prove particularly fruitful.

I haven't used EAC for a long time (I Use dBpowerAMP ripper), but doesn't it have a setting to delete silent samples at the start of files to ensure that the files will line up perfectly when compared?

i.e. an otherwise identical mastering may include slightly different indexing that appears as digital silence just before the track starts?
Title: SHM-CD Format: Hype or Hope?
Post by: dev on 2009-05-22 16:01:10
The propaganda; only thing i can think of, they propably put better mastered tracks to have illusion that there is superior quality thanks to CD, or they don`t even do that, and it`s normal master on better quality CD, maby it can last longer but 1 bit is a 1 bit!.
Title: SHM-CD Format: Hype or Hope?
Post by: itisljar on 2009-05-23 08:57:32
If comp returns a "Files Compare OK" then that means first.wav and second.wav are byte-for-byte exact duplicates.


They are on different sectors. Have you ever considered that?
I am battling with few audiophiles about basic scientific concepts, but to no avail - I've been told that I've walked into "the land of unknown"  .
Title: SHM-CD Format: Hype or Hope?
Post by: Nick.C on 2009-05-23 09:32:31
More like the "land of the unknowing" - I mean, an identical pair of bitstreams is just that, is it not?
Title: SHM-CD Format: Hype or Hope?
Post by: uzernaam on 2010-10-17 10:56:42
... My ones will be more singular, my zeros will be truly nothing.


Haha, somehow that phrase strikes me as really funny.

Yes, I have a very hard time believing that bits can be interpreted by the electronics as anything other than zero or one.
Title: SHM-CD Format: Hype or Hope?
Post by: jimmy69 on 2010-10-17 12:28:24
Holy moly!  The couple of comments about more scratch resistant CDs gave me the best idea. Zagg invisible shield for CDs. Sounds awesome no. Oh and about the difference in sound quality. Why all the discussion? Digital is digital, a bit is a bit end of discussion
Title: SHM-CD Format: Hype or Hope?
Post by: Squeller on 2012-10-24 19:15:44
Well, there's an Article in Stereo magazine (german language). http://www.stereo.de/index.php?id=613 (http://www.stereo.de/index.php?id=613)

They first searched for bit identical CDs (normal vs. shm cd) to avoid comparing different mastering. Well, that's good on the one hand, but on the other IMO they proved that they must sound identical. But in the listening test they heard clear differences, not surprisingly the SHM CD sounds better (english speakers, no need to translate. Some bullshit bingo attributes you already know from listening tests):

Quote
in den oberen Lagen entspannter, weniger glasig, beschwingter, gelöster und dreidimensionaler. Die Normal-CD wirkt dagegen wie eingeschnürt: kompakter und belegter.

That is beyond my logical thinking.
Title: SHM-CD Format: Hype or Hope?
Post by: rod on 2013-11-10 20:25:46
Hi,  is true, bits are bits, but we need bits in the wright time.  A music  teacher said sometime that:
" The correct note in the incorrect time is the incorrect note", is that clear?

For to represent a point in a wave form we need two coordinates ed  X e Y
Y is our famous BIT  and x is the timebase, the exact time in that we need that bit
In the timebase ocurrs a series of infernal mistakes, jitter, read errors imperfections of
the material, the form of the recorded hole in the metal layer, etc

Yes bits are bits but this is not enough, is necesary to consider the above for improve digital audio,
probably SHM-CD did it.

Excuse my english

Rod. from Chile
Title: SHM-CD Format: Hype or Hope?
Post by: db1989 on 2013-11-10 20:53:34
Do you have any evidence that jitter in typical CD players is audibly relevant and that SHM-CD can fix this supposed problem? Otherwise, your post will be no more useful than all the many previous ones where people talked about the supposed perils of jitter but never substantiated any of it.
Title: SHM-CD Format: Hype or Hope?
Post by: lvqcl on 2013-11-10 21:06:49
It's simply not possible to read CD sample by sample: http://en.wikipedia.org/wiki/Compact_Disc_...o#Data_encoding (http://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio#Data_encoding)

So the whole idea that "we need rigth bit in right time" is meaningless.
Title: SHM-CD Format: Hype or Hope?
Post by: extrabigmehdi on 2013-11-10 21:26:47
This thread has been resurrected, so I'd take the opportunity to say that  SHM-CD versions have usually more loudness compression (i.e for the "mastering") , so I'd avoid them as much as possible.
Title: SHM-CD Format: Hype or Hope?
Post by: db1989 on 2013-11-10 22:04:01
Which is nothing inherent to the format, just bad mastering decisions as usual.

If no one can provide any technical basis and evidence that ShakingMyHead-CD offers any benefit over normal CDs, this thread can recede into the archives whence it came.
Title: SHM-CD Format: Hype or Hope?
Post by: unfinished.hide on 2013-11-11 12:20:42
A couple of years ago I came across a SHM-CD, Bon Jovi's Slippery When Wet, which according to its obi was a "reissue of the 1999 remaster as SHM-CD". So I took my copy of the original 1999 remaster and ripped them both to see if I could ABX those superior audio differences claimed by JVC. To my surprise AccurateRip results for both rips were actually identical track by track, except for the offset as two different pressings are expected to differ. Obviously after that I didn't waste my time trying to ABX two bit-identical files as I wouldn't expect to find any difference, let alone an 'audible improvement'.

The very same thing happened with an HQCD (similar technology developed by Toshiba) with a reissue in 2009 on this format of an originally released album in 2005 from a Japanese artist. The label didn't even touch the master in the slightest, so same AccurateRip results, different offsets again.

Since then, and even considering the limited amount of testing I've been able to perform and the simple tools used, my fear is that those newer formats which claim to improve the CD retaining compatibility with CD players are actually snake oil at their best. I mean, if they are only a reissue, then they do improve nothing, but do not make the sound worse either; a completely transparent format. However, as already ponted out before, if they are used to feature a new remaster for the occasion, I would be pretty reluctant to consider them even good.
Title: SHM-CD Format: Hype or Hope?
Post by: knutinh on 2013-11-11 13:41:24
It's simply not possible to read CD sample by sample: http://en.wikipedia.org/wiki/Compact_Disc_...o#Data_encoding (http://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio#Data_encoding)

So the whole idea that "we need rigth bit in right time" is meaningless.

The CD is still a physical format, and there must be some control mechanism wrgt how fast the CD spins, some local clock oscillator, the physical signal on CD and the digital/analog signal pushed out of the CD player. This control mechanism might be implemented with variable degrees of decoupling, stabilisation, delay, cost etc in mind. Intuitively, it sounds like an engineering problem that can be "solved", this does not mean that all solvable engineering problems are solved in practice...

It will be very hard to prove that two CDs that decode into the same PCM bytes using EAC cannot sound/measure different in some other circumstance. I guess that certain "error correction" methods may make this more likely (by messing with the built-in robustness of the CD medium). The diverse implementations of CD players (and records) makes it daunting to try to "prove" that "a bit is a bit".

Happily, the burden of proof cannot possibly be on the sceptic in this case. He who claims that two CD pressings sounds different to him, even though the information bytes are identical, should provide proof in the form of simple ABX tests, some sensible measurement, or accept being seen as something similar to homeopaths and other "believers". Being a believer does not make your conclusions wrong, btw, only the method that got you there (and thus, your conclusions cannot be trusted).

-k
Title: SHM-CD Format: Hype or Hope?
Post by: rod on 2013-11-11 16:03:19
If anyone want to know more about jitter may read the essay:

"Everything you always wanted to know about jitter but were afraid
to ask"  by Bob Katz


Saludos

Rod
Title: SHM-CD Format: Hype or Hope?
Post by: greynol on 2013-11-11 16:41:19
Rather than more hit-and-run posting, maybe you can explain in your own words how a disc is going to influence the timing of a CD player's DAC or the upstream decoder and demodulator before that, assuming you're concerned about the player's digital out.

Do you even have the faintest idea how data is organized on a compact disc?
Title: SHM-CD Format: Hype or Hope?
Post by: krabapple on 2013-11-11 20:07:00
Bob Katz has an unfortunate habit of citing 'blind tests' whose salient details he's never published.

Title: SHM-CD Format: Hype or Hope?
Post by: knutinh on 2013-11-11 20:34:04
Rather than more hit-and-run posting

Please state what post you are referring to.

-k
Title: SHM-CD Format: Hype or Hope?
Post by: pdq on 2013-11-11 20:43:49
Rather than more hit-and-run posting

Are you referencing my post?

-k

I'm sure he was referencing rod's post.
Title: SHM-CD Format: Hype or Hope?
Post by: extrabigmehdi on 2013-11-12 00:37:27
Bob Katz has an unfortunate habit of citing 'blind tests' whose salient details he's never published.


Thanks for the remark ,  I took a quick look to the mentioned paper, and I was a bit disturbed when Bob Katz talked of blind test.
And it seems  he's a famous/popular  audio mastering engineer , so it would tempting to take his writings more seriously.

Title: SHM-CD Format: Hype or Hope?
Post by: Glenn Gundlach on 2013-11-12 06:12:44
The CD is still a physical format, and there must be some control mechanism wrgt how fast the CD spins, some local clock oscillator, the physical signal on CD and the digital/analog signal pushed out of the CD player. This control mechanism might be implemented with variable degrees of decoupling, stabilisation, delay, cost etc in mind. Intuitively, it sounds like an engineering problem that can be "solved", this does not mean that all solvable engineering problems are solved in practice...

<snip>

-k

The job of the servos (plural) is to keep the disc speed correct and the laser beams (plural) properly focused and on track. The LENGTH of the pit is the EFM binary value that gets looked up to convert back to plain binary. The data is not recorded sequentially in order to cover burst errors. Disc damage will come in spurts of 'N' bytes long and it's difficult to fill in big holes so the data is 'scrambled' by writing into RAM line by line and reading it out column by column. The reverse is done during playback. So, instead of having one big 'N' byte long hole you end up with 'N' 1 byte holes. Error detection and correction data is added during record. Small numbers of errors can be 100% corrected and bigger errors get interpolated which is obviously not good but the disc has to be pretty messed up to get to interpolation.

More error correction is added for data mode when used for files. Programs can tolerate no errors and still work correctly so the basic medium has to be pretty robust.

Timing errors off the disc show up as a variable write speed into the descrambling RAM and when read out with the stable clock all your jitter is gone. It's called Time Base Correction and has been done in video for over 50 years so it was nothing new for CDs, just an even better implementation than in early video TBCs

Bottom line is if the disc could not be bit perfect, it would never be useful for software.

Some players ARE more tolerant of poor discs - better servos and analog signal processing. Remember, there is no such thing as a digital recorder. The digital signal controls an analog signal that gets recorded, transmitted or transfered so anything that distorts the analog signal potentially degrades the digital signal encoded into the analog stream. Don't believe me? Get a scope and look at digital transmissions and recordings. BTW it's what I do for a living in broadcast TV.