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Author Topic: Copies and Bit Accruacy.  (Read 13938 times)

The Watcher

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Re: Copies and Bit Accruacy.
« Reply #15 on: October 17, 2006, 03:24:50 PM »

bblackwood wrote on Tue, 17 October 2006 15:14

Matt, did you notice anyone else on the panel straining their extra-ocular muscles whilst rolling their eyes?


hah well in the actuall scean only Joe is in frame, and he looks alittle uncomfortable.

Also in attendance is.

Steve Smith form Avastore, who says some cool things and seems to be on his game, Im supposed to meet him in a week or to so Ima DEFINITLY bring this up.

and Rick Senischall (Spelling?) Who manages the Audo Group for Microsoft Studios.

thier is alos a host named Glena Lorbecki
Matt
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Jack Schitt

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Re: Copies and Bit Accruacy.
« Reply #16 on: October 17, 2006, 03:46:12 PM »

This is nonsense. There are tools in place specifically to make sure copies are bit accurate. They HAVE to be to function in databases, OS's etc that are far more stringent than digital audio.  

These kinds of outragous claims give everyone a black eye. I suppose he invented the question mark too? Smile

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bblackwood

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Re: Copies and Bit Accruacy.
« Reply #17 on: October 17, 2006, 03:52:33 PM »

Hey, it's all about "hearing better" than everyone else. They might even believe it by now...

Sad.
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Brad Blackwood
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Bob DeMaa

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Re: Copies and Bit Accruacy.
« Reply #18 on: October 17, 2006, 04:24:28 PM »

Friend of mine does work for Joe. He's told me on a number of occasions that Joe says he can hear the difference in an audio file after it's been copied to another drive. I prefer to not have an opinion either way til I can duplicate the results myself, but I'm very skeptical.

They also tell me they hear a difference between using RTAS or TDM version of the same plug-ins. I haven't tried to distinguish this myself yet.
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Andy Peters

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Re: Copies and Bit Accruacy.
« Reply #19 on: October 17, 2006, 04:40:23 PM »

The Watcher wrote on Tue, 17 October 2006 12:05

Anyway.  Bernie says that he "Very concerned with putting the best product out that you can" so there for requests the ORIGINAL hard drive the mix was ORIGINALLY printed to.  He claims that you cannot copy digital data around from drive to drive without expecting some sort or "quality loss".  He lists in oder or best to worst in QUALITY of the sound.

1.  Original drive
2.  Clone of Original Drive, he claims that while there will be a little quality loss    here it will be minimal.
3.  The DVD or Cd-R.  DATA only of course.

He definitely makes claims that simply copying of digital to digital form drive to drive will lessen the quality of the signal.


That's so wrong it's not even funny.  See my other post.

I am sorry; he may be a very-well respected mastering engineer, etc, etc, but he's still so very wrong.

The only thing worse than believing this sort of nonsense is spreading it as gospel.

-a
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Legacy

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Re: Copies and Bit Accruacy.
« Reply #20 on: October 17, 2006, 05:08:01 PM »

Not that I'm weighing in one way or the other but what about jitter?  Not just interface jitter (device to device AES etc) but sampling jitter or the kind that affects all data transfer systems including firewire / USB etc.  The descriptions of subtle degradation sound like classic jitter induced sonic changes.  They can be such gremlins to track down when it rears its head.  It wouldn't surprise me at all if Bernie Grundman could hear quite minute ammounts of jitter....

I ask this not to open a can of worms but because it is an area that I'd like to learn more about.

-Silas

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Silas Brown
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Roland Storch

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Re: Copies and Bit Accruacy.
« Reply #21 on: October 17, 2006, 05:44:12 PM »

More on that subject you can find here:
http://www.digido.com/modules.php?name=News&file=article &sid=15
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rankus

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Re: Copies and Bit Accruacy.
« Reply #22 on: October 17, 2006, 06:16:56 PM »



I read a few years back that the CDR acceptable error rate is x00 errors per second....(can't recall exact number but it was in the hundreds)

Someone had done some testing on multi generation CDR to CDR transfers of audio, and found that they could hear a generational loss at approx. 14 generations....

I can't recall where I got this data, but I'm fairly sure my recollection is correct (it had better be before I post here).

To back this up a quick Google search yields:

http://www.mrichter.com/cdr/primer/errors.htm

I personaly don't worry about this with only single generation copies....
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The Watcher

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Re: Copies and Bit Accruacy.
« Reply #23 on: October 17, 2006, 07:09:22 PM »

Here what I really think on the subject. Much or what we call the job of being a professional audio type guy is soooo very subjective.  I mean I really thought for a minute that summing boxes actually did somthing to the signal from a DAW other than add the inherent noise of the summing system to the signal, the summing had nothing to do with it.

Wheneven I make a statment that syas "X is not X' its really Y and yall dont relize it"  I try to make sure I have good hard data to back it up.  Such as a Phase Null Test.  I Mean its physics at that point.  It either is or isnt right?  It nulls or it dont.

Now if Bernie has such Data, and Id like to think he does if he made a stament like this infront of a buncha Naras board members, that thast a whole nother story.  

To the Bob DeMaa  if I was you friend who works with Joe whe he sais he can hears somthing, if you have the luxury of investigating with a null test, do it.  

The main problem with digital is that no one wants to come up with real hard data thats easy to understand.  I would like to think that I could take a mix in a DAW, copy it back n forth 50 times, then burn that to DVD then Reload the session bounce the orig, the copied 1, and the one from DVD and they would phase null.  I will try this inight, if they dont, we need to find out why, if they do you can bet I will be bginging this up at the next Chicago chapet meeting, and the "Truth and Lies in Digital Audio" Even on th 27th.

If your in Chicago it is gonna be at the NARAS office and Tony Masaratti will be speaking.

Matt
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Jus for the record, I usta post under kakaroto, but times, they a changin, big ups to nomad, shotgun, ded4now, skywaidu and all the other from the good ol crypt days.

hollis

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Re: Copies and Bit Accruacy.
« Reply #24 on: October 17, 2006, 07:23:51 PM »

Did anyone catch the mastering panel at AES SF? This exact kind of thing came up a few times, and nobody stomped it out. It was a little hard to believe in a room full of audio industry.

Then again, I learned the speed of sound for the 100th time in an acoustics workshop (at AES!), so maybe there is still room to mold young minds.
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Andy Peters

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Re: Copies and Bit Accruacy.
« Reply #25 on: October 17, 2006, 07:59:46 PM »

Legacy wrote on Tue, 17 October 2006 14:08

Not that I'm weighing in one way or the other but what about jitter?  Not just interface jitter (device to device AES etc) but sampling jitter or the kind that affects all data transfer systems including firewire / USB etc.  The descriptions of subtle degradation sound like classic jitter induced sonic changes.  They can be such gremlins to track down when it rears its head.  It wouldn't surprise me at all if Bernie Grundman could hear quite minute ammounts of jitter....

I ask this not to open a can of worms but because it is an area that I'd like to learn more about.


Jitter has absolutely nothing to do with data transfers over Firewire or USB or IDE or SCSI or ...

-a
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jtr

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Re: Copies and Bit Accuracy
« Reply #26 on: October 17, 2006, 08:10:57 PM »

There are so many variables at work here, too many to make such an absolute pronouncement.   I'm willing to entertain the idea that a specific workstation setup might be giving inconsistent results because of drive performance or power supply fluctuations....etc.etc.etc.  There must have been some sort of observation made, but the conclusion is far from an "always".

For someone to claim they can always hear differences between the original drive and clones, suggests that they've gone everywhere and heard this "phenomenon" in every installation. Not likely.  And probably never tested with anything resembling a scientific listening test with sufficient repeated listenings, double blind , and so forth.

This takes us back to the classic "I can hear the difference, can't
you?"  approach, at which point we all pull out our mastering rulers to see whose is bigger.  
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bblackwood

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Re: Copies and Bit Accuracy
« Reply #27 on: October 17, 2006, 08:13:52 PM »

jtr wrote on Tue, 17 October 2006 19:10

There are so many variables at work here, too many to make such an absolute pronouncement.   I'm willing to entertain the idea that a specific workstation setup might be giving inconsistent results because of drive performance or power supply fluctuations....etc.etc.etc.  

The computer wouldn't even work if there were errors like that. Much less play back audio files.

If they are truly hearing those differences, I question the quality of their equipment!

Quote:

This takes us back to the classic "I can hear the difference, can't
you?"  approach, at which point we all pull out our mastering rulers to see whose is bigger.  

Exactly.
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Brad Blackwood
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Andy Peters

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Re: Copies and Bit Accruacy.
« Reply #28 on: October 17, 2006, 08:16:14 PM »

rankus wrote on Tue, 17 October 2006 15:16

I read a few years back that the CDR acceptable error rate is x00 errors per second....(can't recall exact number but it was in the hundreds)


Red Book specifies two levels of Reed-Solomon coding, which if you weren't lazy like me, you could look up and find out exactly how many errors are correctable.  It's obvious that it's a fairly robust system.  But that's for audio.  I don't recall the exact ECC used for CD data discs, but suffice it to say: it works.

Quote:

Someone had done some testing on multi generation CDR to CDR transfers of audio, and found that they could hear a generational loss at approx. 14 generations....


Here's the deal.  A corrected error is indistinguishable from no error occuring at all.  That's the magic behind error correction and convolutional coding.  If you're getting uncorrectable errors, it's likely that the disc is damaged, or the mechanism that's reading the disc is damaged.

To be honest, I don't know if those CD-R duplicator thingies read raw bits from the disc and make the dupes that way, or if they actually read and decode the data before writing.  I suspect that they do the latter, since the IDE interface gives you the decoded data, not the raw bits.  (The drives do all of the work.)

Having said all of that: it's fairly simple to test to see if you've got identical data after n-generation copies.  Simply write a program that reads the data from the original disc, and also reads the data from the copy disc, and compare.  No magic "nulling" or any other silliness (like a listening test) -- just a direct data compare.

And, again, back to the original hard drive vs the data copied onto another hard drive argument: if you couldn't copy data from one drive to another without 100% absolute confidence the copy would be identical, we wouldn't be having this discussion, as none of our computers would work.

-a
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Legacy

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Re: Copies and Bit Accruacy.
« Reply #29 on: October 17, 2006, 08:32:46 PM »

Quote:

Andy Peters wrote on Tue, 17 October 2006 19:59
Jitter has absolutely nothing to do with data transfers over Firewire or USB or IDE or SCSI or ...

-a




Actually jitter is an issue (and is the term used to descride sub-sample timing errors) in many areas of high-speed data transmission including Serial ATA and PCI Express and I believe any form of data transmission where minute timing delays can be introduced offsetting the transitions from bit to bit although perhaps not for Firewire or USB as you say. I don't recall.

From  http://webevents.broadcast.com/cmp/wcs/detail.asp?event_id=1 1493 :
"Jitter is one of the most difficult measurement problems facing digital design and signal integrity engineers today. As data rates increase, the impact of jitter on device and system performance becomes more and more challenging. With jitter now specified in several leading high-speed serial buses like PCI Express and Serial ATA, how do you make quality measurements of total jitter, random jitter, and deterministic jitter? Are you able to discern the different components of deterministic jitter so that you can isolate the causes of jitter in your design? New techniques are now available to help address these issues. This presentation will discuss these new techniques and contrast them with existing methodologies. Several applications will be discussed, reviewing the measurement needs, the different types and amounts of jitter that are present, and how designers can utilize new techniques to tackle their jitter problems"

I'm the first one to say that I don't understand this much but I do get the feeling that there is more to learn about data transmission in the digital realm....I also guess that we need to further refine our terms when it comes to removeable transmission jitter versus that which is permanently affecting the data.  In either case it is not an audio exclusive term.

-S
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Silas Brown
Legacy Sound
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