Why jitter doesn’t matter

[Vincent Kars]

Its easier for me to simply rip music to my Toshiba notebook’s built-in hard drive initially.
Then copy to external USB drive. But if I do this in this manner, is there an accuracy/jitter problem with the copy on the external USB drive?

Post like these are common.

Digital audio is complex but sometimes it is just like vinyl.

If you move a record from one shelve to another, will this affect the content?
Likewise you can move a digital audio file from one HD to another without changing the content.

If you play an LP why do you play it at 33 rpm?
Well it is written on the sleeve to do so.
If you play a 16 bits / 44.1 kHz audio file it will be played at 44.1 kHz.
This is simply written in the header of the file.

But what about the jitter?

If you play a record there will be wow & flutter.
This is not a property of the record but a property of the turntable.
Likewise there will be small variations in the time step (jitter) when playing digital audio.
This is not a property of the file but a property of the clock driving the DA conversion.

An audio file is what it is, just a file.
You can edit it, copy it, tag it, etc. but only when it is converted to analog jitter is of relevance.
Rule of the thumb: jitter only matters when somebody is listening.

Only the paranoid survive so is this completely true?
No, flaky PC memory can corrupt data.
This might go unnoticed for some time.
It is a good strategy to have a backup of your audio.
It is even better to have an old backup because it might take some time before you notice your files are corrupt.

 

[fas42]

Only the paranoid survive so is this completely true?
No, flaky PC memory can corrupt data.
This might go unnoticed for some time.
It is a good strategy to have a backup of your audio.
It is even better to have an old backup because it might take some time before you notice your files are corrupt.

This of course is a variation of my proposing a "brilliant but fiendishly evil" individual wanting to rid the world of all music: whenever there is a situation where you, the user, are in charge of making sure that your data, in this case music, is safe from corruption then Murphy's Law will apply ...

Frank

 

[Johnny Vinyl]

Why does my MediaMonkey software have a RIP option that says: Jitter-corrected Read, when (as you say) jitter only comes into play when listening? It also has on option for :Secure Read (takes more time).

 

[microstrip]

Post like these are common.

Digital audio is complex but sometimes it is just like vinyl.

If you move a record from one shelve to another, will this affect the content?
Likewise you can move a digital audio file from one HD to another without changing the content.

If you play an LP why do you play it at 33 rpm?
Well it is written on the sleeve to do so.
If you play a 16 bits / 44.1 kHz audio file it will be played at 44.1 kHz.
This is simply written in the header of the file.

But what about the jitter?

If you play a record there will be wow & flutter.
This is not a property of the record but a property of the turntable.
Likewise there will be small variations in the time step (jitter) when playing digital audio.
This is not a property of the file but a property of the clock driving the DA conversion.

An audio file is what it is, just a file.
You can edit it, copy it, tag it, etc. but only when it is converted to analog jitter is of relevance.
Rule of the thumb: jitter only matters when somebody is listening.

Only the paranoid survive so is this completely true?
No, flaky PC memory can corrupt data.
This might go unnoticed for some time.
It is a good strategy to have a backup of your audio.
It is even better to have an old backup because it might take some time before you notice your files are corrupt.

Vincent,

A file has physical existence - these 0 and 1s are electrical or magnetic data. There will be a "data flow" between the file and the DAC input. This "data flow" is an electrical process, that needs energy and can produce electrical noise, and can indirectly influence the clock of the system, and in some cases different file formats can influence sound quality. I read some people claim that even the way the file is written in the hard-disk can influence the sound.

You can easily assure that the same bits will be at the input of the DAC. But assuring that all the electrical signals will be exactly with the same values and timing to the picosecond level is a different assumption.

 

[amirm]

Why does my MediaMonkey software have a RIP option that says: Jitter-corrected Read, when (as you say) jitter only comes into play when listening? It also has on option for :Secure Read (takes more time).

Jitter is a generic term applied to many different things. In the above, it refers to the fact that when you seek on audio CDs, the drive may actually go further ahead or behind where you told it to go. For playing audio that is fine. But for reading blocks of audio to store on hard disk, that can create duplicate or missing audio samples -- neither one of which is good. This is called a "seek jitter." The meaning here is that the location that the drive goes to is subject to variation or jitter. All CD extraction tools/programs have logic to deal with this by reading more than is needed and finding the overlap/missing samples. That is what the above option does.

Vincent's point is correct in that *once you have your data copied to hard disk* then jitter becomes immaterial.

 

[amirm]

Vincent,

A file has physical existence - these 0 and 1s are electrical or magnetic data. There will be a "data flow" between the file and the DAC input. This "data flow" is an electrical process, that needs energy and can produce electrical noise, and can indirectly influence the clock of the system, and in some cases different file formats can influence sound quality. I read some people claim that even the way the file is written in the hard-disk can influence the sound.

You can easily assure that the same bits will be at the input of the DAC. But assuring that all the electrical signals will be exactly with the same values and timing to the picosecond level is a different assumption.

Microstrip, in this context the above issues do not count. The original question was whether ripping to an internal drive and then copying the bits to an external drive results in different bits than copying to the external drive directly. The answer is what Vincent gave. The results are identical and we can compare the files to confirm.

That is different than where you are going that if you play from internal drive vs external drive, that the results are different. As Vincent says, in this case you are involving the DAC so there can be differences in the analog output. In the above sequence, the DAC is not involved so this is not a factor. Yes, there are differences in how the data is fetched but by the time it becomes digital data read by your computer and stored on hard disk, it is one in the same.

 

[Johnny Vinyl]

Jitter is a generic term applied to many different things. In the above, it refers to the fact that when you seek on audio CDs, the drive may actually go further ahead or behind where you told it to go. For playing audio that is fine. But for reading blocks of audio to store on hard disk, that can create duplicate or missing audio samples -- neither one of which is good. This is called a "seek jitter." The meaning here is that the location that the drive goes to is subject to variation or jitter. All CD extraction tools/programs have logic to deal with this by reading more than is needed and finding the overlap/missing samples. That is what the above option does.

Vincent's point is correct in that *once you have your data copied to hard disk* then jitter becomes immaterial.

Thanks Amir for that explanantion. I think I will set my MM to read my discs as such when ripping.

 

[microstrip]

Microstrip, in this context the above issues do not count. The original question was whether ripping to an internal drive and then copying the bits to an external drive results in different bits than copying to the external drive directly. The answer is what Vincent gave. The results are identical and we can compare the files to confirm.

That is different than where you are going that if you play from internal drive vs external drive, that the results are different. As Vincent says, in this case you are involving the DAC so there can be differences in the analog output. In the above sequence, the DAC is not involved so this is not a factor. Yes, there are differences in how the data is fetched but by the time it becomes digital data read by your computer and stored on hard disk, it is one in the same.

Amir,
Thanks for clarifying the issue. I was mislead by the comparison of jitter to wow and flutter. Jitter can be affected by the data content in digital systems and classical wow and flutter is a property of the playing system - although some people refer that the drag of stylus in the vinyl groove due to modulations also affects sound quality.

 

[Vincent Kars]

1 Why does my MediaMonkey software have a RIP option that says: Jitter-corrected Read, when (as you say) jitter only comes into play when listening?
2 It also has on option for :Secure Read (takes more time).

Ad 1: an optimism I don’t share
Ad 2: always do, nothing wrong with a secure rip. But I do prefer dbPoweramp

 

[Johnny Vinyl]

Ad 1: an optimism I don’t share
Ad 2: always do, nothing wrong with a secure rip. But I do prefer dbPoweramp

Hi Vincent and Gelukkig NieuwJaar!

Why do you prefer dbPoweramp? Does it offer something for ripping that MediaMonkey does not?

 

[Vincent Kars]

Hi John

Beste wensen!

Partly emotion, it is a very good product.
It supports AccurateRip: http://www.accuraterip.com/ a nice check