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Your welcome.

Not very successful thread,boring subject , should stop.:)

 

Please don't, even though it only interests people who don't already know everything, and want to learn rather than argue.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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Please don't, even though it only interests people who don't already know everything, and want to learn rather than argue.

 

+1

 

BTW, this thread might be more active if you could explain things in simpler terms for idiots like myself.

 

For example, you seem to imply that Alex's observation that identical data stored on a hard drive can somehow sound different but I can't see the explanation based on the references you provided. Can you help us connect the dots?

 

I would like to believe that Alex is right but so far no one has come up a plausible explanation.

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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Reading all this information it's clear that there are lot of technical issues influencing data extraction from audio cd's. The main question I'm not getting an actual answer on is what the main cause for different sounding rips could be, rephrase, what the cause(s) could be if there were to exist different sounding rips from the same source material.

 

-Unreadable blocks and/or read errors causing different error corrections?

-Am I correct in assuming "jitter" only has an audible effect on realtime playback? I understabd burned cd's of varying burn quality cause varying amounts of jitter on read, can this have any effect on the bits being written to harddrive?

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+1

 

BTW, this thread might be more active if you could explain things in simpler terms for idiots like myself.

 

For example, you seem to imply that Alex's observation that identical data stored on a hard drive can somehow sound different but I can't see the explanation based on the references you provided. Can you help us connect the dots?

 

I would like to believe that Alex is right but so far no one has come up a plausible explanation.

 

Tom I never said that identical data may sound different, I say identical checksum may sound different.

in the statement I also said that CRC is independent of data values.

I also explained in" how to store jitter" the effect on amplitude so the dot are easy to connect.

 


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Reading all this information it's clear that there are lot of technical issues influencing data extraction from audio cd's. The main question I'm not getting an actual answer on is what the main cause for different sounding rips could be, rephrase, what the cause(s) could be if there were to exist different sounding rips from the same source material.

 

-Unreadable blocks and/or read errors causing different error corrections?

-Am I correct in assuming "jitter" only has an audible effect on realtime playback? I understabd burned cd's of varying burn quality cause varying amounts of jitter on read, can this have any effect on the bits being written to harddrive?

 

You are connecting the dots :) there is more info coming and we can draw the evident conclusion all together.

 

Thanks to you, to Jud and Tom at least now I know that I'm not writing for myself:)

 


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Tom I never said that identical data may sound different, I say identical checksum may sound different.

in the statement I also said that CRC is independent of data values.

 

I guess this is the part that I am missing.

 

For example, Alex provided me with two files that he insists sound different. I calculated the checksum of both files and did a byte by byte comparison of the files and as far as I can tell they are identical. Are you saying that they may be different?

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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I guess this is the part that I am missing.

 

For example, Alex provided me with two files that he insists sound different. I calculated the checksum of both files and did a byte by byte comparison of the files and as far as I can tell they are identical. Are you saying that they may be different?

 

I understand, you are talking bit and Im talking sample value, ok take an example for a 3T pit you may have a smaller amplitude in the read out signal due to the length effect but you still represent it by 001.

 

*I have also checked the 2 files from Alex and they were exactly the same but his subjective statement pushed me to do some research and I thank him for that.

 


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I understand, you are talking bit and Im talking sample value, ok take an example for a 3T pit you may have a smaller amplitude in the read out signal due to the length effect but you still represent it by 001.

 

This matches my understanding. The signal may have a lower amplitude but there is no mechanism for capturing this lower amplitude in the digital data that is written to the HDD when the CD is ripped.

 

It is also my understanding that there can only be two types of rips: one that match the binary data on the CD (correct ones) and ones that don't (incorrect ones).

 

Alex has observed rips that seem to fall between the two. They are correct and identical to each other at the binary level but the quality varies according to the power supplied to the drive during the ripping process.

 

I don't believe that such rips can exist. What do you think?

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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This matches my understanding. The signal may have a lower amplitude but there is no mechanism for capturing this lower amplitude in the digital data that is written to the HDD when the CD is ripped.

 

It is also my understanding that there can only be two types of rips: one that match the binary data on the CD (correct ones) and ones that don't (incorrect ones).

 

Alex has observed rips that seem to fall between the two. They are correct and identical to each other at the binary level but the quality varies according to the power supplied to the drive during the ripping process.

 

I don't believe that such rips can exist. What do you think?

 

We didn't finish to link the dot,3T is the smallest value but if you have a smaller amplitude in the read out signal what will happen to a 4T? you will read it as 3T than it's represented by 001 instead of 0001.

when we will go further in explanation with sector, data chunk , block error read,splicing in checksum you will understand that's why I told it need a demonstration.

 


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We didn't finish to link the dot,3T is the smallest value but if you have a smaller amplitude in the read out signal what will happen to a 4T? you will read it as 3T than it's represented by 001 instead of 0001.

when we will go further in explanation with sector, data chunk , block error read,splicing in checksum you will understand that's why I told it need a demonstration.

 

If the amplitude drops below the threshold level and the data changes from 0001 to 001, this will be a read error and, if this error is uncorrected, the resulting rip will have a different checksum than a rip in which the data didn't change from 0001 to 001, right?

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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It is also my understanding that there can only be two types of rips: one that match the binary data on the CD (correct ones) and ones that don't (incorrect ones).

 

Alex has observed rips that seem to fall between the two. They are correct and identical to each other at the binary level but the quality varies according to the power supplied to the drive during the ripping process.

 

I don't believe that such rips can exist. What do you think?

 

If that were possible, computers as we know them could not exist. In fact, the universe as we know it couldn't exist under such circumstances.

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If the amplitude drops below the threshold level and the data changes from 0001 to 001, this will be a read error and, if this error is uncorrected, the resulting rip will have a different checksum than a rip in which the data didn't change from 0001 to 001, right?

 

In theory yes, but real data are different animals.

 


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In theory yes, but real data are different animals.

 

I understand that it is possible for different files to have the same checksum but the chances of this occurring in the situation are so small that I think we can ignore this as a possibility. Also, as I mentioned above, I compared the data at the byte level and found it to be identical.

 

Alex has said that you have proposed phase shift and the hall effect as reasons why identical data files may sound different. I am having a hard time with this as I believe these factors are only applicable when data is being read from the CD. Once the CD has been ripped, there is only binary data and these factors don't come into play. Is my understanding incorrect?

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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I understand that it is possible for different files to have the same checksum but the chances of this occurring in the situation are so small that I think we can ignore this as a possibility. Also, as I mentioned above, I compared the data at the byte level and found it to be identical.

 

Alex has said that you have proposed phase shift and the hall effect as reasons why identical data files may sound different. I am having a hard time with this as I believe these factors are only applicable when data is being read from the CD. Once the CD has been ripped, there is only binary data and these factors don't come into play. Is my understanding incorrect?

 

No my message was phase shift=same checksum=different sound.

 


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No my message was phase shift=same checksum=different sound.

 

Can you explain what this means?

 

Is this also true?

 

phase shift=same bits on the HDD=different sound

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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No didn't say the same bits in HDD=different sound.

As said already that I will explain my findings.

 

Thanks for the clarification. I look forward to hearing more when you are ready.

 

All the best,

 

Tom

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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Thanks for the clarification. I look forward to hearing more when you are ready.

 

All the best,

 

Tom

 

Tom,

 

Just for clarification I never said and will never say that identical bits sound different, I just tried to find out why Alex and others can hear a difference.

I could see only two possibilities the data are spread on different packets that may affect the bit rate(BER) or it make the jitter higher during the reading process or the non uniformity of the checksum is the culprit.

I had to start first with the behaviour of the optical drive to try to explain what happening first and if the two possibilities can be covered.

So please let's forget about the bits are bits war, and let's continue to try to find what is behind the mathematical assumptions.

And anyhow if at the end you are not convinced by my demonstration I'm sure that in any case you are learning stuff about the optical drive:)

 


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Tom,

 

Just for clarification I never said and will never say that identical bits sound different, I just tried to find out why Alex and others can hear a difference.

I could see only two possibilities the data are spread on different packets that may affect the bit rate(BER) or it make the jitter higher during the reading process or the non uniformity of the checksum is the culprit.

I had to start first with the behaviour of the optical drive to try to explain what happening first and if the two possibilities can be covered.

So please let's forget about the bits are bits war, and let's continue to try to find what is behind the mathematical assumptions.

And anyhow if at the end you are not convinced by my demonstration I'm sure that in any case you are learning stuff about the optical drive:)

 

Thanks again for clarification.

 

I am looking forward to your demonstration.

 

For the record, here is what I believe on this subject:

 

- There are only two kinds of rips: ones that match the data on the CD (accurate rips) and ones that don't (inaccurate rips).

 

- It is not possible to have a "better sounding" accurate rip or two accurate rips that sound different. All accurate rips that are bit-identical should sound the same when played through the same playback chain. If they don't, the cause is external to the data itself. An example would be HDD fragmentation.

 

- A better quality CD drive or better power to an existing CD may improve playback quality. It may also make it easier to obtain an accurate rip by reducing read errors, etc. It will not result in a better sounding rip if the rip is accurate.

Sometimes it's like someone took a knife, baby
Edgy and dull and cut a six inch valley
Through the middle of my skull

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But.. How can you be sure your rip is accurate, compare your rip to the accurip database? Im not convinced since Ive had different accurip checksums on different drives while all were reported as accurate!

 

That works if the drive (or a drive dependent variable like offset) is part of what goes into the checksum.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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That works if the drive (or a drive dependent variable like offset) is part of what goes into the checksum.

 

Hi Jud,

 

I will explain the drive offset in the manufacturer interpretation but as some of you are in hurry to see in witch direction I'm going.

 

 

First this may help:Differences Between CRC And Checksum | Difference Between | Differences Between CRC And Checksum

 

Second the reason why ripping software use CRC 32 is that it will detect the majority of errors by checking:

Any 1 bit error

Any two adjacent 1 bit errors

Any odd number of 1 bits errors

Any burst of errors with a length of 32 or less

Majority it's not all, what if with overlapping we have a burst longer than 32 bits?

 

That's what the demonstration is about: accuracy...

But getting there needs lot of thing to be explained before jumping to the conclusion that different bits may sound different:)

 


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I am glad I found this thread. Since it is hard to get Plextor drive, I got myself Samsung SE-506 blu ray external slotted drive instead few months ago. It is not ideal but at least ripping no more generate vibration at my laptop (run with LPS) using its internal drive and causes a lot of ripping errors and software EAC hanged. I use an audio grade usb A to B type cable, to join with another DIY short connector (B female to micro B male type) to use with the drive for cd ripping.So if I am thinking to rip (no pun intended!) the SE-506 drive apart to trasfer only the tray and its electronics to another sturdy aluminium casing and modify an usb connector to tap its power line to provide very good external 5v LPS to the drive, will it work and perform much better (less jitter) in ripping cd?

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