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11-02-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 26
Post ID: 17302
Reply to: 17301
Please, get familiar with Compact Disc structure
fiogf49gjkf0d
 item wrote:
It's a very novel sensation for me to be arguing that 'bits are bits'! But its very simple to prove categorically that the binary data on the disc is identical to the ripped version.

More importantly, where there are errors, they are punctiliar and rare. In other words, it's hard to imagine how they could combine systemically to change the 'character' of the file. This idea is exactly like saying 'my digital photograph changes colour when I move it to a different partition'. In a very unusual scenario, you might lose a pixel, or corrupt a file header, but it will never turn sepia!

The behaviour of the optical drive will make a characteristic difference to the 'colour' of the playback. We can look to the hardware - and even software - but we can't blame the data.
Item,

there is no arguing from my side. Sorry but you are a bit to equipped even to understand the subject of argument. Moving a stream of bytes from one partition to another is very much not the same as moving bytes from optical disk to wave byte stream. You need to educate your on the subject how CD is made and what CD reading involved, read about frames, 14-bit words, synchronization words, sectors, data cross-interleavness , Reed-Solomon reconstructions,  random and burst errors etc…..  There is a LOT of processing involved to read Compact Disc and to output bits. Your Hi-Fi Review editor shall explain it to you. Anyhow, good luck with your file-playing computers, I am sure they are wonderful but I would advise to stay away from calling your machines “transports” and it is misleading.

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-02-2011 Post does not mapped to Knowledge Tree
item
Posts 14
Joined on 11-02-2011

Post #: 27
Post ID: 17303
Reply to: 17302
In the rost post-CD future
fiogf49gjkf0d
Let's just be grateful things have moved on from those nasty plastic discs . . . in an ideal world I like to call the future, we would download our files from the mixing desk direct to our highly optimised audio computers/streamers/digital transports and music would never get tangled up in optical media, with all its resource-hungry correction and crude mechanical apparatus. In the meantime, MD5 checksums (for instance) give us complete confidence that a copied file is 100% accurately transferred from disc. Playing that file as well as the disc-spinner is the benchmark computers have aspired to, but in many cases have now surpassed.

In similar vein to our machines, Romy (which you're not likely to hear over there), have you tried the Auraliti players? They're capable of pretty nifty performance.
11-02-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 28
Post ID: 17304
Reply to: 17303
Acute file playing syndrome?
fiogf49gjkf0d
 item wrote:
Let's just be grateful things have moved on from those nasty plastic discs . . . in an ideal world I like to call the future, we would download our files from the mixing desk direct to our highly optimised audio computers/streamers/digital transports and music would never get tangled up in optical media, with all its resource-hungry correction and crude mechanical apparatus. In the meantime, MD5 checksums (for instance) give us complete confidence that a copied file is 100% accurately transferred from disc. Playing that file as well as the disc-spinner is the benchmark computers have aspired to, but in many cases have now surpassed.

Item, I am sorry but what you recite is nothing more then marketing BS that has absolutely nothing to do with reality. Where do you get your downloaded files? The file providers make the files for you from CDs. In fact to have them on CD is good as it gets rid of the chance that some kind of idiot in the middle would love to manipulate with the files. When you download then how do you know what is on another side? It very much might be some kind of stupid Moron that pumps into feed 96K MP3 files and upside them to 192kHz. It happens all over the net and your journalist-editor shall address that instead of writing unnecessary BS about a new toy that juts pretrial for ads for the next 6 month. Your willingness to celebrate “benchmark computers” is fine but this is only very shallow side of problem. I appreciate your enthusiasm if you only just discovered the PC-based playback but I am assure you that you will go over it in future.
 item wrote:
In similar vein to our machines, Romy (which you're not likely to hear over there), have you tried the Auraliti players? They're capable of pretty nifty performance.

Nope, I do not know them and I am not looking to any file playing machines. I have my DAW and it is enough for me. I would be much interested for option to my DAW to play CD in real time from some kind CD-Rom, or what I call “transport” mode. Unfortutly as I said not of the CD-roms (real-time, buffered or memory) read disks with demanded level of quality.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-02-2011 Post does not mapped to Knowledge Tree
oxric
Posts 194
Joined on 02-12-2010

Post #: 29
Post ID: 17305
Reply to: 17284
Little coherence and even less relevance to your arguments. In this thread.
fiogf49gjkf0d
 Romy the Cat wrote:

 oxric wrote:
By analogy, an Item Audio equipped with an optional blu-ray drive would serve precisely this function. It would spin a disc, extract the data and code it so that it is available for the next stage in the chain.

Yes it might but it needs to do it in real time. I do not think at this point Item Audio “transport” performs this rudimental transport duty.

 oxric wrote:
Reviewer bashing Romy? Without knowing who it is and what was said?

Why do I need to know who and under which circumstance said anything? Any persons who practice audio not for own benefits but for interests of “others” as far as I’m concern might go fuck himself. I understand that you do not “get” it yet but you do see me insisting that you obliged to get anything, do you. Please do not response to it.

The Cat


There is little need to respond to any of it Romy. Whilst the points you make about the evolutionary flaws embedded in redbook show the shortsightedness of the designers or technological limitations in the days leading to the launch of the Compact Disc, this thread was not about redbook playback but about a Transport which does what it says on the tin and extracts data, codes it and sends it to your favourite DAC with little ado and irrespective of the format you started with, be it a high resolution download or music on some physical media.

How this thread however turned out to be one about semantics and then about cd playback and redbook is indeed baffling. Personally, I cannot imagine many companies investing in improving cd playback. It is a dead end, not least because the problems enumerated were caused by shortsightedness on the part of those behind redbook and things will ultimately move on, to high res media and downloads once the music industry get its act together. If one wants to achieve ultimate quality from cd, they should just hold on to their favourite cd player/transport combination and use that as a source. That's what I do. It's not as convenient maybe but so is playing LPS or 78s, or that FM broadcast you recorded to tape. Ours is unfortunately a painful pursuit and there is little chance of anyone coming along who will resolve all your digital transport woes in one fell swoop. It's somewhat like that long list of criteria you wanted some off-the-shelf unit for your Opera Room receiver to satisfy, that would have universal transport, onboard DAC and amplification, for the paltry sum of $1000. Reality is different.

Of course, being a programmer of some description and versed in the dark arts of redbook data extraction, error correction and transfer, I imagine you might well consider spending a week-end producing this ideal digital transport you have been waiting for instead of whinging that commercial units brought to market do not satisfy your own very personal criteria or non-universal definitions.

Best regards
Rakesh

  
11-02-2011 Post does not mapped to Knowledge Tree
item
Posts 14
Joined on 11-02-2011

Post #: 30
Post ID: 17306
Reply to: 17304
O . . . K . . .
fiogf49gjkf0d
On a really fundamental level, this conversation isn't working. Good luck with the site, and happy listening (digital or analog).
MW
11-02-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 31
Post ID: 17307
Reply to: 17305
The name "transport" did mislead me.
fiogf49gjkf0d
Oxric, I have no idea what your “literature” was all about. If the Item’s company does not name thier read-only DAWs as “transport” it would be no conversation at all. For sure the analog PS for PS that they do is very interesting thing and very much unknown thing but they have no guts of apparent expertise to make any claims about sonic benefits of it. They use a feedback of some kind of idiot-reviewer and some kind of reference. Pay attention that the feedback was not about sound of DAW but how it compares to some kind of CD transport – how much more idiotic it could be, particularly know that this machine is NOT a transport. Anyhow, I do not make any claims about their DAWs and perhaps Item is not a technical or sonic brain of the company. It might be a good machine and you need to buy it right, after renew your subscription to Hi-Fi Review.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-02-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 32
Post ID: 17308
Reply to: 17306
Ok.
fiogf49gjkf0d
 item wrote:
On a really fundamental level, this conversation isn't working.

No, it is OK, I did not expect a lot more. Your analog power supplies are interesting. I never tried it and when I heard other people did them they reported controversial results. For sure you will not be able to report on it as it wools require you to reread what your Hi-Fi review editor told. It is OK, I know it is hard, so many sound from so many directions. Drop the name “transport” and it will  be the best benefit you can get from this conversation.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-02-2011 Post does not mapped to Knowledge Tree
miab
Canada
Posts 46
Joined on 02-07-2008

Post #: 33
Post ID: 17309
Reply to: 17300
Reading into it further
fiogf49gjkf0d
 Romy the Cat wrote:

It was exactly what I was experimenting for many times since 2005 and I came to exactly opposite finding. I am not able to make neither LP, tape or CD to copy in digital that would sound like original source. I am able to do it with FM – I can record it and to play undistinguishable but no other souses that I have. But what do I know – I do not run the Hi-Fi review but from another hands I so not sell to anybody my concussions... You do.


Romy,

If you were to copy cd to digital in your DAW and then retransfer it to a recordable cd, does your transport then play it exactly as the original cd? If yes I think this might indicate that there is hope in finding a way to reproduce the qualities through you DAW that your transport reveals. Items effort might not be in vain. If no then there seems to be a fundamental flaw in digitization of cd's that is irreversible. No amount of linear supplies and isolation (hardware and software) would help. Although this experiment would not prove absolute fact, the evidence would lean in that direction.

Interesting is that you can record FM indistinguishable from source but not your LP's or tape (other analog sources). Have you looked further into this?
11-02-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 34
Post ID: 17310
Reply to: 17309
You need to differentiate....
fiogf49gjkf0d
Miab, you need to differentiate between a CD and the 16/44 uncompressed wav file. They are VERY different things. A very best CD has I would say no more the 40% of quality of that 16/44 uncompressed wav file is able to care.  I just only wish if people instead of converting wav file to CD destitute files as data CD in wav format.  There are reasons why it is not practicable, however….


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-03-2011 Post does not mapped to Knowledge Tree
item
Posts 14
Joined on 11-02-2011

Post #: 35
Post ID: 17312
Reply to: 17307
Definition
fiogf49gjkf0d
 Romy the Cat wrote:
Oxric, I have no idea what your “literature” was all about. If the Item’s company does not name thier read-only DAWs as “transport” it would be no conversation at all. For sure the analog PS for PS that they do is very interesting thing and very much unknown thing but they have no guts of apparent expertise to make any claims about sonic benefits of it. They use a feedback of some kind of idiot-reviewer and some kind of reference. Pay attention that the feedback was not about sound of DAW but how it compares to some kind of CD transport – how much more idiotic it could be, particularly know that this machine is NOT a transport. Anyhow, I do not make any claims about their DAWs and perhaps Item is not a technical or sonic brain of the company. It might be a good machine and you need to buy it right, after renew your subscription to Hi-Fi Review.


For future reference, in case anyone else is as confused as I am about the content of this thread; from the horse's mouth: the Item DAT1 could just about be considered a 'DAW' (the SPDIF version records analog, and you can run editing and mixing suites on it). However, it is a CD converter (it rips CDs to AIFF, WAV, FLAC, etc files). It is a CD player. Above all - it is a universal digital file player and streamer with onboard storage.

Whether:
a) That makes it a 'transport' as you understand it,
b) All reviewers are idiots,
c) Linear supplies are generally better than switching supplies
d) File-based transports are generally better than optical drive transports,
e) The DAT1 performs better or worse than Device X . . .

. . . I have no further comment to make about such controversial or subjective matters, and I don't want to be seen to be promoting our machine: only to set the record straight about what it is and does.

Whether or not ripping a CD or engaging in other forms of digital > digital conversion modifies it systematically and characteristically is a separate conversation altogether.

As far as we're concerned, it's a rather short one, although it resurfaces occasionally on various forums in different guises. Any mathematical transformation of data involves a degree of necessary interpolation or filtering that can, to some extent, (generously) be considered 'lossy'. Any conversion from D>A or A>D plunges into a complex world of quantisation pain. However, although (as Romy points out) the throughput involves several layers of housekeeping error correction when ripping CDs, converting PCM data involves no transformation beyond modification of header data. No quantisation or approximation - just a copy, a backup: moved from A to B like any common or garden file transfer. It's not voodoo elf powder: it's just data.

Nailing this shut absolutely, though, is the fact that we can easily perform bit-for bit comparison of the CD contents with the file with 100% accuracy. There's no room to hide: individual bit errors stick out like sore thumbs. To imply that the resultant, perfect clone somehow 'sounds different' implies a systemic alteration to the file that simply isn't possible to ascribe to the data itself. It is possible (inevitable, actually) that each OS handles uncompressed file formats (WAV, AIFF) differently that could - just about, in theory - affect the file transport behaviour in real time, but it's a long shot.

It remains highly controversial whether the effect of on-the-fly decompression of lossless formats such as ALAC and FLAC create audible artefacts (in certain systems, it does appear to), but - again - a mechanism for the idea that 'my CD lost something in translation' has never been proposed, and currently seems untenable. We really can't blame the data. Which means that, providing the header and metadata are correctly formatted, any bit-perfect RIP made on any drive with any software is precisely and absolutely as good as any other, and is fully the equal of the CD.

Having said that, there is some wriggle room for two identical rips to perform differently because of their different positions on the drive and possible fragmentation, resulting in a different pattern of interrupts and EM noise created by different patterns of drive read access. But again, many find this stretches the limits of plausibility.

The problem is that you can never made a level playing field comparison between a CD and its ripped clone, because the hardware is so instrumental in the performance of the transport.
11-03-2011 Post does not mapped to Knowledge Tree
item
Posts 14
Joined on 11-02-2011

Post #: 36
Post ID: 17313
Reply to: 17312
What's the mechanism?
fiogf49gjkf0d
If you built a machine purely as a CD converter, it would be interesting to experiment with different power supplies to determine whether a higher number of errors get through the sieve when rail noise is higher. It has been well documented that different CD-ROM mechs create higher or lower read errors, and obviously these are not desirable, but from the playback viewpoint, once the file is encoded, the processor takes the file as read: it's not error checking against the CD.

Again, we're missing even the flimsiest theoretical framework for a mechanism by which one in a million bit errors during ripping can translate to any characteristic difference in the resultant file. Especially when we consider that during playback those micro rip 'errors' are not errors at all: they look like valid data.
11-03-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 37
Post ID: 17315
Reply to: 17313
Do you call your lawn mower as a digital transport”?
fiogf49gjkf0d

 item wrote:
For future reference, in case anyone else is as confused as I am about the content of this thread; from the horse's mouth: the Item DAT1 could just about be considered a 'DAW' (the SPDIF version records analog, and you can run editing and mixing suites on it). However, it is a CD converter (it rips CDs to AIFF, WAV, FLAC, etc files). It is a CD player. Above all - it is a universal digital file player and streamer with onboard storage.

Any computer does absolute the same level of universality by being a digital file player. My telephone does it but I do not call my telephone a “digital transport”.  Ripping CD it is not what your devise does but the free software that you use. So, any other PC would do it.

 item wrote:
I have no further comment to make about such controversial or subjective matters, and I don't want to be seen to be promoting our machine: only to set the record straight about what it is and does.

No one prohibit you to make promotional statements but you need to live with consequences if your statements are not accurate or do not make any sense. In your commentary that content of audio CD is identical to a wav file and could be bit-for bit compared you went to pure world of fantasy.

 item wrote:
It remains highly controversial whether the effect of on-the-fly decompression of lossless formats such as ALAC and FLAC create audible artefacts

Why is it controversial is in case of  FLACing the bit-for bit comparing before and after is perfectly possible?

 item wrote:
Having said that, there is some wriggle room for two identical rips to perform differently because of their different positions on the drive and possible fragmentation, resulting in a different pattern of interrupts and EM noise created by different patterns of drive read access. But again, many find this stretches the limits of plausibility.

Why you suddenly give a room to possibility of any wriggling if you insist that bit-for-bit comparing between audio CD and bit stream file is possible? If you have two digital cables with very different sound then are you sure that they will not pass your bit-for-bit test? What, do you think that one of the cables is just losing bits somewhere during transition?

 item wrote:
The problem is that you can never made a level playing field comparison between a CD and its ripped clone, because the hardware is so instrumental in the performance of the transport.
yes, the hardware is very instrumental in the performance of the transport and you in your devise have no specialty hardware to be a transport. You stick in your PS $15 CD room drive and make EAC to rip the data from the disk. Absolutely any computer, including my TV, phone and perhaps a refrigerator can do it but I do not call them digital transports.

 item wrote:
If you built a machine purely as a CD converter, it would be interesting to experiment with different power supplies to determine whether a higher number of errors get through the sieve when rail noise is higher. It has been well documented that different CD-ROM mechs create higher or lower read errors, and obviously these are not desirable, but from the playback viewpoint, once the file is encoded, the processor takes the file as read: it's not error checking against the CD.

Errors are absolute irrelevant. The EAC make you to be informed about error and all sales people begin to run mouth about errors. The data on CD is duplicated (multiple times in some cases) and the first level of error are the errors the might be recovered from different sectors. Some of the errors could not be recovered and there are different ways to deal with it. To talk about connection between the differences in PS and the error correction algorithms is like talking about connection between difference in results of multiplication table at different altitude above sea level.
 item wrote:
Again, we're missing even the flimsiest theoretical framework for a mechanism by which one in a million bit errors during ripping can translate to any characteristic difference in the resultant file. Especially when we consider that during playback those micro rip 'errors' are not errors at all: they look like valid data.

Why suddenly you begin to talk about errors? Did you read something recently? You just was keep taking about direct bit-to-bit conversion between CD and file and insisted the it is as same as copy file between two patricians. Why suddenly “errors” became a new bid wolf. You need to read more or to ask somebody to explain it to you. The errors them are not a big deal and the errors are not the cause of the change in the sound that we hear with different transports. Again, talk to your magazine editor. They are very basic things and he shall be able to explain it to you. Writing those pretentious marketing proclamations you need at least to be informed what you saying.

Rgs,
Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-03-2011 Post does not mapped to Knowledge Tree
item
Posts 14
Joined on 11-02-2011

Post #: 38
Post ID: 17320
Reply to: 17315
AardGRIB.
fiogf49gjkf0d
 Romy the Cat wrote:
Any computer does absolute the same level of universality by being a digital file player. My telephone does it but I do not call my telephone a “digital transport”.  Ripping CD it is not what your devise does but the free software that you use. So, any other PC would do it.

Yes, the hardware is very instrumental in the performance of the transport and you in your devise have no specialty hardware to be a transport. You stick in your PS $15 CD room drive and make EAC to rip the data from the disk. Absolutely any computer, including my TV, phone and perhaps a refrigerator can do it but I do not call them digital transports.

Why suddenly “errors” became a new bid wolf. You need to read more or to ask somebody to explain it to you. The errors them are not a big deal and the errors are not the cause of the change in the sound that we hear with different transports. Again, talk to your magazine editor. They are very basic things and he shall be able to explain it to you. Writing those pretentious marketing proclamations you need at least to be informed what you saying.


Romy, you're special! This conversaRTGhujition is like try[ing to use a - hey! - 4Ghu o > calculator with   r un-%%%down EGGpLANT batteries . . .


woof.

I'm fascinated about what you believe, and which part of the theme park we're in.
Please tell me about why transports differ, and what's good and bad about computer hardware (especially CD-ROM drives) and software in an audio system . . .
11-03-2011 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 39
Post ID: 17321
Reply to: 17320
Graduated from a Audio Reviewing University?
fiogf49gjkf0d
It is OK, Item. It is a common for people who sell audio to be not completely informed what they are selling. That comes with territory. You might discover with time that audio is much more interning then just to dump a pile of BS on people and to make him to pay for it. If you figure out what else audio might be then come again and perhaps we can compare notes about analog power supplies for computers. Until then I find this conversation is too boring. The people who learned how to jerk black boxes in order to demonstrate to audio-morons that the there is some billable difference in Sounds are not the level of audio intelligence with which I am accustom to socialize.  I am sure you make wonderful PS music servers. Are you servers good for anything the then to cut fish on them? Well, one the first who need to learn the answer. From what you have advocated in this thread I see only confusion from you. The Hi-fi Review Cum Laude diploma uselessly does it to people…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-03-2011 Post does not mapped to Knowledge Tree
manisandher
London
Posts 158
Joined on 09-05-2008

Post #: 40
Post ID: 17322
Reply to: 17321
A thought experiment
fiogf49gjkf0d

1) I play a CD on an 'excellent' CD transport. I take the digital output from this (spdif or AES) and connect it to a PC interface (a Lynx or RME card). I capture the digital output on the PC as a .wav file using Wavelab or something similar.

2) I rip the CD to a .wav file using EAC or DBPoweramp.

3) I play both files back using the same PC and software player.

Would the two files sound different? If so, why? (Unfortunately, I don't have an 'excellent' CD transport to hand, otherwise I would try this.)

Mani.

11-03-2011 Post does not mapped to Knowledge Tree
item
Posts 14
Joined on 11-02-2011

Post #: 41
Post ID: 17323
Reply to: 17322
Mmmm . . . experiment
fiogf49gjkf0d
A fine experiment to try . . . can I suggest a checksum as well as an audition? It's not an entirely fair fight, though . . . the ripper has the luxury of time and verification.
04-11-2018 Post does not mapped to Knowledge Tree
Amir
Iran Tehran
Posts 299
Joined on 02-11-2009

Post #: 42
Post ID: 24801
Reply to: 17323
Ripping a CD
if ripping data is different to CD Transport streaming data then no audio files could sound better than CD Transport.I found no useful data to explain me why ripping by computer CD Rom could not get all stored data from CD!
04-11-2018 Post does not mapped to Knowledge Tree
Amir
Iran Tehran
Posts 299
Joined on 02-11-2009

Post #: 43
Post ID: 24802
Reply to: 24801
Capture Transport Data by PC
I can not convince myself that "Transport reads data as apple and CD rom reads data as orange". if I have seen this claim in another forum then I could not believe it .
we know EAC and dbpoweramp and other secure audio cd ripping softwares have CRC codes.if you (and other people across the world) rip Pink Floyd album with dbpoweramp then you will find over 10000 people around the world ripped that album with exact the same CRC codes.it means the ripped files is exactly the same over the world because all CRC codes are equal.
if we believe cdplayer read different then we should believe Sony/philips do not let cd roms to decode audio perfectly. I think it is possible but I hardly believe it.
the only way to find the trust is to connecting CEC TL0-X output to PC and capture incoming data and storing in wav format then comparing it with ripped wav file.
https://en.wikipedia.org/wiki/Kees_Schouhamer_Immink
https://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio


"The Red Book specifies the physical parameters and properties of the CD, the optical "stylus" parameters, deviations and error rate, modulation system (eight-to-fourteen modulation, EFM) and error correction facility (cross-interleaved Reed–Solomon coding, CIRC), and the eight subcode channels. These parameters are common to all compact discs and used by all logical formats, such as CD-ROM.  "
04-11-2018 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,571
Joined on 10-12-2006

Post #: 44
Post ID: 24803
Reply to: 24802
"Digital Sound"
Amir, I am a long way from understanding the digital audio chains or how they interact, and how each transition affects sound I can get at home.  The biggest reason I have only "invested" in CD so far is because this has been the only digital source I have heard "promising" sound from.  I look forward to hearing good music from streaming sources, and I will also share here if it ever happens.


Best regards,
Paul S
08-13-2018 Post does not mapped to Knowledge Tree
Amir
Iran Tehran
Posts 299
Joined on 02-11-2009

Post #: 45
Post ID: 25037
Reply to: 17295
CRC Code
 Romy the Cat wrote:
fiogf49gjkf0dItem,

you are not getting the point that ripping implied the initial read of CD by CD-ROM drive and their possess looks like kills the quality of the file you made on your “super PC”. If you imply that your PC plays a file that was not made from the same CD then you compare apples and oranges. Making claims that “well-designed PC transport is better than a good CD transport” is a ridicules claim if your CD-ROM and your CD transport use different source. Again take the same CD, play it at your CD passport. Then rip the same CD to your super-duper PC and play it into the dame DAC. If you find that your PC outperform you CD transport then… trash your CD transport and get the one that sound better, not the one that your magazine editor told your that that it “sounds good”.

Rgs,
Romy the Cat

if Ripped Files from CD Rom drives are not good (or they are not equal to uncompressed raw files) then why all ripped files have equal CRC Code?

This is the AIFF log file ripped by dbpoweramp :  
Encoder: AIFF 
Extraction Log--------------
Track 1:  Ripped LBA 0 to 22015 (4:53) in 1:56. Filename: /Volumes/Transcend/Buffer Rip 44 16/01  - Track 1.aif
  CRC32: 5F14D8A9     AccurateRip CRC: FD86ACBE (CRCv2)     [DiscID: 013-001d29a6-0123fc46-a00d770d-1]
08-14-2018 Post does not mapped to Knowledge Tree
Amir
Iran Tehran
Posts 299
Joined on 02-11-2009

Post #: 46
Post ID: 25038
Reply to: 25037
Raw file Size vs Ripped Aiff file Size
un-compressed RAW file -> optical Disc -> Ripped File   

putting RAW files on optical Disc is a process (it may be lossy, I don't knowMark claims A disc containing 74 minutes and 33 seconds of music contains 6.3 billion bits. Of all those bits only 33% are audio bits, with the rest being overhead. )

Ripping optical Disc is a process (romy thinks it is lossy, I do not know)


un-compressed RAW file = pure PCM 44100/16bit

optical Disc Capacity is 74min for 44100/16bit

Ripped File Size (AIFF) is 74min for 44100/16bit


if RAW file Size is equal to Ripped File Size and they sound different then ripped file should be filled with un-correct data.if ripped files filled by un-correct data and all CRC codes are equal then CD-Roms all have equal reading mechanism but they could not read all data like CDplayers.it means CDplayers could read all data and cd-roms could not read all data and files on PC contain un-correct data.
I think we need a man describe it to us. I have found no information in internet.




I have emailed Gordon Rankin and he think AIFF is equal to Optical Disk Data :
"Not that I am going to read this because it's total BS, but they probably don't mention that they are using the same drives that are in computers and therefore have the worse problems reading on the fly compared to reading it more than ounce. "
08-15-2018 Post does not mapped to Knowledge Tree
Amir
Iran Tehran
Posts 299
Joined on 02-11-2009

Post #: 47
Post ID: 25039
Reply to: 25038
65min Audio Data and 74 min Audio Data plus Other Codes
https://www.cdmediaworld.com/hardware/cdrom/cd_techinfo.shtml
https://en.wikipedia.org/wiki/CD-ROM
Facts:
  • One sector holds 2352 bytes of AUDIO.
  • The DATA Transfer-rate
=
=
=
=
sampling rate * channels * audio bitsize
44100 * 2 (stereo) * 16 (16 bit) bits/second
1411200 bits/second
176400 bytes/second
Sector Transfer rate
=
=
176400/2352 sectors/second
75 sectors/second
1 MByte AUDIO    
=
=
=
1048576 bytes
1048576/2352 sectors
446 sectors
333000 sectors 
=
=
=
=
333000/75 seconds
4440 seconds
4440/60 minutes
74 minutes
333000 sectors 
=
=
333000/446 Mbytes AUDIO
747 Mbytes AUDIO

The reason why an AUDIO CD  holds more data/sector lays in the fact that it uses the complete 2352 bytes to store AUDIO in one sector. This means that an Audio-Byte is per default corrupt as there is no CRC checking. Due to hardware datacorrection these errors are not heard.

This method can not be used for a Data-Bytes as the data would be corrupt. To fix this problem a DATA sector contains both Data and CRC-CCITT Information.

CRC-CCITT is a 16 bit EDC (Error Detecting Code). For every byte of data a 16 bit CRC code is calculated, resulting in 128 CRCs, 16 bits each. These CRCs, therefore, take up 256 bytes of the 2352 bytes available. The remaining 48 bytes are reserved for future use. This leaves 2048 bytes available for actual Data.





It seems 65min of 74min is audio data (2048 bytes of 2352) . the only thing could convince me the ripped audio data is not equal to optical disk is that cd rom could not read correct data and cdplayer could do that.

08-19-2018 Post does not mapped to Knowledge Tree
Amir
Iran Tehran
Posts 299
Joined on 02-11-2009

Post #: 48
Post ID: 25040
Reply to: 25039
DAE Firmware quality
I have find not all CD Roms have equal firmware to read audio data. some firmwares do not report errors correctly .http://www.exactaudiocopy.de/en/index.php/other-projects/dae-quality/
it seems ripping could give us 100% correct data  if we have a good firmware but I do not know which cd-rom drives have those good firmwares.

  
   
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