Re: mind melt
Johan,
I do not claim there is a differencce between original and CDR
(I have only done a few experiments a long time ago) but since
many report differences, one should perhaps keep an open
mind. So let me just point out some errors in your reasoning.
A CD is not digital. It is a physical medium which is used to
encode digital data as a stream of lands and pits. These are not
perfect. There is variation in the lengt and depth profiles of these,
there is always some variation in thickness and transparency of
the transparent layer, variation i the dye layer, variations in the
reflective layer etc. A CD is an analog medium, used to store
digital data. All these factors affect how well we can record
and retireve the data from the disc. This applies also to the
original pressed CD, of course, and these are usually of low
quality compared to good CDR: the disc itself is thinner and
less stable, the reflective layer is thinner and made of aluminium.
There is a big difference between audio CDs and data CDs. An
audio CD is read in realtime and the data format is such that
you cannot reread data without rereading a whole track. A data
CD on the other hand stores the data in blocks which can be
read individually. When a read error occurs, an audio CD player
cannot reread the data, while a CDROM device will just go back
and read the block again.
Yes, but unless we are certain that the datastream is read
correctly, this could be an explanation for differences in sound.
I am not quite sure how CD players usually work, but presumably
there must be some kind of PLL to synchronise the read clock
with the noisy analog signal from the laser. So I suppose
variations both in the recorded data and the speed of CD player
could affect the bit error rate. After clocking the data, there
should be no effect, assuming a sound digital design.
Johan,
I do not claim there is a differencce between original and CDR
(I have only done a few experiments a long time ago) but since
many report differences, one should perhaps keep an open
mind. So let me just point out some errors in your reasoning.
johan.vikstrom said:
A CD is not digital. It is a physical medium which is used to
encode digital data as a stream of lands and pits. These are not
perfect. There is variation in the lengt and depth profiles of these,
there is always some variation in thickness and transparency of
the transparent layer, variation i the dye layer, variations in the
reflective layer etc. A CD is an analog medium, used to store
digital data. All these factors affect how well we can record
and retireve the data from the disc. This applies also to the
original pressed CD, of course, and these are usually of low
quality compared to good CDR: the disc itself is thinner and
less stable, the reflective layer is thinner and made of aluminium.
There is a big difference between audio CDs and data CDs. An
audio CD is read in realtime and the data format is such that
you cannot reread data without rereading a whole track. A data
CD on the other hand stores the data in blocks which can be
read individually. When a read error occurs, an audio CD player
cannot reread the data, while a CDROM device will just go back
and read the block again.
Yes, but unless we are certain that the datastream is read
correctly, this could be an explanation for differences in sound.
I am not quite sure how CD players usually work, but presumably
there must be some kind of PLL to synchronise the read clock
with the noisy analog signal from the laser. So I suppose
variations both in the recorded data and the speed of CD player
could affect the bit error rate. After clocking the data, there
should be no effect, assuming a sound digital design.
Re: Re: mind melt
Yupp (half true)
A cd is read with a laser, the signal is decoded and a 'bitstream' is sent to a DAC.
The DAC (digital audi converter) has imporves alot since '80. That is the what you and other hears
The digital reading and sending of the bitstream is of less importance since a zero or a one can only be that, there is nothing like a bad "zero". If the signal is to distored a error will occure.
Any correction to the quality of the sound should be done on the DAC or after.
Peter Daniel said:
If the above was true, we would be still happy with cd players made in '80s with no need to upgrade, because they were producing perfect sound forever.
History proves otherwise.
Yupp (half true)
A cd is read with a laser, the signal is decoded and a 'bitstream' is sent to a DAC.
The DAC (digital audi converter) has imporves alot since '80. That is the what you and other hears
The digital reading and sending of the bitstream is of less importance since a zero or a one can only be that, there is nothing like a bad "zero". If the signal is to distored a error will occure.
Any correction to the quality of the sound should be done on the DAC or after.
Re: Re: mind melt
You know, some CD drives have become better but my old and slow Denon DC-1500 plays damaged CD's excellent because of the slowness. Faster drives get nervous when they see a real big gap in the data. But I don't deny that the DAC is a little bit old. The machine has LC-filters, YES.
Peter Daniel said:If the above was true, we would be still happy with cd players made in '80s with no need to upgrade, because they were producing perfect sound forever.
History proves otherwise.
You know, some CD drives have become better but my old and slow Denon DC-1500 plays damaged CD's excellent because of the slowness. Faster drives get nervous when they see a real big gap in the data. But I don't deny that the DAC is a little bit old. The machine has LC-filters, YES.
Re: Re: mind melt
Yes, I'm open and I belive that i perhaps will find a difference in the sound. What it depends on is the most important part.
Since the DAC runs on a separate clock all the CD (and transport) need to do is to feed enough data to the DAC. Remember that digitals streams zero and ones is by definition allowed to flux in length.
If there is read or conversions error in the process there will changes in the sound, but I can't belive that CD players are of so low quality.
I belive that the early part of the decoding of the CD is of low importance.
The last and most important clocking is done in the DAC and when the analog signal is created. Before that there is also a clocking but that clock is allowed a flux.
conclusion.. (do you agree?)
If there is problem for the cd and electionics to read the cd there can be a differance when you copy a CD.
Is it possible that CD players are so bad that they cause read error, that each time you play a CD it will sound slightly different.
Christer said:
Yes, I'm open and I belive that i perhaps will find a difference in the sound. What it depends on is the most important part.
Correct, but a good DAC will show errors in the bitstream. Since souch error is very rare, the reading of the CD can't be of any importance. If the data is read correctly then it's up to the DAC to make sound of it.
Since the DAC runs on a separate clock all the CD (and transport) need to do is to feed enough data to the DAC. Remember that digitals streams zero and ones is by definition allowed to flux in length.
If there is read or conversions error in the process there will changes in the sound, but I can't belive that CD players are of so low quality.
I belive that the early part of the decoding of the CD is of low importance.
The last and most important clocking is done in the DAC and when the analog signal is created. Before that there is also a clocking but that clock is allowed a flux.
conclusion.. (do you agree?)
If there is problem for the cd and electionics to read the cd there can be a differance when you copy a CD.
Is it possible that CD players are so bad that they cause read error, that each time you play a CD it will sound slightly different.
Re: Re: Re: mind melt
Did you ever tried to buitd CD transport yourself? I did and can assure you that it has the same importance as DAC, if not bigger.
johan.vikstrom said:
Yupp (half true)
A cd is read with a laser, the signal is decoded and a 'bitstream' is sent to a DAC.
The DAC (digital audi converter) has imporves alot since '80. That is the what you and other hears
The digital reading and sending of the bitstream is of less importance since a zero or a one can only be that, there is nothing like a bad "zero". If the signal is to distored a error will occure.
Any correction to the quality of the sound should be done on the DAC or after.
Did you ever tried to buitd CD transport yourself? I did and can assure you that it has the same importance as DAC, if not bigger.
Maybe it is a little misleading to say that the burned CD sound better than the original or the other way round. It is the player sounding different playing the variations I would say. I have read various explanations to this preposterous/actual fact and reasons for differences either way may be:
CD-Rs have different reflection properties than original CDs. Less/More precise reading - Less/More error correction - Less/More jitter - Less/More spurious reflections.
CD-Rs have (or so I hear) a different topology (grooves/no grooves) compared to standard CDs with different tracking/auto-focus properties for the player. See previous results.
CD-Rs could be better centered than burned. Standard CDs may be slightly off-center (but oh so slightly). See previous results.
Please also note that many claim to hear differences between recording speeds. Slow copy it seems give the best result. Today copying at 40+ speeds is a perfect data copy but possibly not a perfect audiophile copy. Try a single speed copy and compare it with a 16 speed copy for instance.
Myself? ALL copies I had (Yes, had I don't have single copy left) sound dull and laid back. Didn't like them at all as a matter of fact. Possible need for new computer gear identified - darn...
/UrSv
PS. johan.vikstrom. Are you confusing these things to be ideal compnents (no offense intended)? My stuf is real world gear and they work not quite according to marketing descriptions...
CD-Rs have different reflection properties than original CDs. Less/More precise reading - Less/More error correction - Less/More jitter - Less/More spurious reflections.
CD-Rs have (or so I hear) a different topology (grooves/no grooves) compared to standard CDs with different tracking/auto-focus properties for the player. See previous results.
CD-Rs could be better centered than burned. Standard CDs may be slightly off-center (but oh so slightly). See previous results.
Please also note that many claim to hear differences between recording speeds. Slow copy it seems give the best result. Today copying at 40+ speeds is a perfect data copy but possibly not a perfect audiophile copy. Try a single speed copy and compare it with a 16 speed copy for instance.
Myself? ALL copies I had (Yes, had I don't have single copy left) sound dull and laid back. Didn't like them at all as a matter of fact. Possible need for new computer gear identified - darn...
/UrSv
PS. johan.vikstrom. Are you confusing these things to be ideal compnents (no offense intended)? My stuf is real world gear and they work not quite according to marketing descriptions...
Johan,
Yes the crucial question is the one about read errors. Read
errors do occur. The question is how often non-correctable
read errors occur. We had a discussion on this a couple of days
back in the thread about blue lasers. I was told many years
ago in a HiFi-shop nearby that they had done experiments on
their best CD player (this might have been 15 years ago),
connecting a frequency counter to the signal indicating read
errors and got quite a high frequency. On the other hand
Steve Eddy said that he and some friends had done a similar
experiment on a number of different players and found that
the non-correctable read errors were extremely rare. It could
be that the people I spoke to had actually measured all
read errors, including the correctable ones. Both I and some
of my friends have seen a tendency that CD players of rigid
mechanical build tend to sound better. Perhaps it is just
coincidence, otherwise I suspect it must have to do with
read errors.
Yes the crucial question is the one about read errors. Read
errors do occur. The question is how often non-correctable
read errors occur. We had a discussion on this a couple of days
back in the thread about blue lasers. I was told many years
ago in a HiFi-shop nearby that they had done experiments on
their best CD player (this might have been 15 years ago),
connecting a frequency counter to the signal indicating read
errors and got quite a high frequency. On the other hand
Steve Eddy said that he and some friends had done a similar
experiment on a number of different players and found that
the non-correctable read errors were extremely rare. It could
be that the people I spoke to had actually measured all
read errors, including the correctable ones. Both I and some
of my friends have seen a tendency that CD players of rigid
mechanical build tend to sound better. Perhaps it is just
coincidence, otherwise I suspect it must have to do with
read errors.
Re: Re: Re: Re: mind melt
Nupe, never built a CD transport.
Is it not like this..
If the signal to the DAC is withour digital errors then the transport does the work good enough ?
My DAC is costing 30k$ so I did some serious visits to resellers to check nice CD transports before I decided that I could remove my CD and go for a DVD as CD transport. There was not possible to hear any difference when I tried a transport for 30k$ and a DVD for far less.
Perhaps I'm wrong, but I wish that someone can prove how a CD transport can improve my system. (that is the main goal- to improve my system).
Blind test has so far failed, perhaps I did get unlucky and runned into expensive but bad transports.
Peter Daniel said:
Did you ever tried to buitd CD transport yourself? I did and can assure you that it has the same importance as DAC, if not bigger.
Nupe, never built a CD transport.
Is it not like this..
If the signal to the DAC is withour digital errors then the transport does the work good enough ?
My DAC is costing 30k$ so I did some serious visits to resellers to check nice CD transports before I decided that I could remove my CD and go for a DVD as CD transport. There was not possible to hear any difference when I tried a transport for 30k$ and a DVD for far less.
Perhaps I'm wrong, but I wish that someone can prove how a CD transport can improve my system. (that is the main goal- to improve my system).
Blind test has so far failed, perhaps I did get unlucky and runned into expensive but bad transports.
Actually this is exactly I am experiencing, but the deteriation is very subtle, it takes a couple of days for the difference to get noticed, then I used the Bedini Ultra Clarifier to treat the CD and everything back to normal and the process repeat with the same CD, especially after the CD has been used in my car, then I notice the deteriation right away when play the CD in the house.
But how come no body mention (ditther/ditter don't know the spelling of the word) when we are talking about the digital 0 and 1 wave form and convert to analog sino wave forms?
Christer said:
This is interesting, because my DAC shows errors feed to it from the source. The errors from a CD are very rare, from a digital sat reciver the errors are more common.
I must admit that I can't tell what errors are detected, i asume that if using PCM there is bit error that can occure. I'm not sure if that is due to signal error or if the transport sends wrong information.
Will it be possible to conenct a digital output from a CD into a digital input on a computer, and run same cd several times. Then after a few recordings, do a binary compare ?
Re: Re: Re: Re: Re: Re: mind melt
Why not ?, only because i'm dumb enough to set 30k into a DAC does not mean that I can't think.
Why should I accept something that does not 'compute'.
Nobody should be happier that me if I could gain anything from improving my transports.
I do not buy the "all things can't be measured or calculated", it it was so, we should not have places a man on the moon.
Sometimes it's more easy to construct something with the ears and the feelings, but it can surely be measured and explained.
The tranpost issue has so far not been explained, unless read errors are common.
flutters are not real
Peter Daniel said:
You must be seriously joking.
If you really had 30k$ DAC you wouldn't write any of the nonsense you just did in this thread.
Why not ?, only because i'm dumb enough to set 30k into a DAC does not mean that I can't think.
Why should I accept something that does not 'compute'.
Nobody should be happier that me if I could gain anything from improving my transports.
I do not buy the "all things can't be measured or calculated", it it was so, we should not have places a man on the moon.
Sometimes it's more easy to construct something with the ears and the feelings, but it can surely be measured and explained.
The tranpost issue has so far not been explained, unless read errors are common.
flutters are not real
Re: Re: Re: Re: Re: Re: Re: Re: mind melt
Arrrrghh.
Do not tell me such things
It did sound nice and it did look even nicer, perhaps i could have found one found for less money, perhaps i could have been happy with a cheaper one. (it has some more functions, but it was mainly as a pure DAC i invested in it)
Peter Daniel said:
You just said that. If you subscribe to the above point of view, the 30k$ DAC purchase would never be justified and realized.
Arrrrghh.
Do not tell me such things
It did sound nice and it did look even nicer, perhaps i could have found one found for less money, perhaps i could have been happy with a cheaper one. (it has some more functions, but it was mainly as a pure DAC i invested in it)
Hello,
I’m living in Serbia and regarding the original and copied cd’s that means two things:
1. last 10 years we did not have so many original discs to buy;
2. last 10 years we did not have so much money to buy original discs.
This country is overwhelmed with copied cds.
Every ordinary audiophile in this country listened a lot of copied cd’s. And spent some time evaluating its qualities. It is not easy to find here anyone who will claim improvements on copies. There are some people whose “job” is manufacture and sale of such discs, and even they rarely claim better sound of copies.
Many times I made original vs. copy A/B test. Copies were made on different burners, with different software, with different speeds, with different media, also tried “on-the-fly” copy. Still, I’m not an expert for this, but...
Neither copy was as an original. Main problems are those Peter mentioned. More compressed and less high frequency extension. And more dry and more aggressive. However, many copies are quite acceptable quality and quite listenable. Interesting, but I can not say there were differences between the readers/burners. Neither change of the speed do much of anything. On-the-fly (+ real-time copy) surely doesn’t reduce the difference between the original and the copy. The only way to influence the sound I found is usage of EAC. It makes the copy not to sound dry and aggressive, but also there is an obvious loss at the upper treble. EAC have this effect as extracting, just as the burning software.
And in whole this story, I don’t see a reason why copies couldn’t be “bit identical” to originals. Of course if you don’t make some error and cd is not damaged. How computers could work if copies couldn’t be a “bit identical”?
I just checked two wav files extracted from one audio cd. One is extracted with EAC, the second with AudioCatalyst. They are practically the same. Just a few different characters in the starts of the files. From the expirience I know the files extracted in EAC and AudioCatalyst do sound different. So, it will be very interesting to learn some day what is the point here.
Pedja
p.s.: Johan, you paid 30K$ for DAC and came to diy area? Maybe you will copy CDs because originals are expensive?
I’m living in Serbia and regarding the original and copied cd’s that means two things:
1. last 10 years we did not have so many original discs to buy;
2. last 10 years we did not have so much money to buy original discs.
This country is overwhelmed with copied cds.
Every ordinary audiophile in this country listened a lot of copied cd’s. And spent some time evaluating its qualities. It is not easy to find here anyone who will claim improvements on copies. There are some people whose “job” is manufacture and sale of such discs, and even they rarely claim better sound of copies.
Many times I made original vs. copy A/B test. Copies were made on different burners, with different software, with different speeds, with different media, also tried “on-the-fly” copy. Still, I’m not an expert for this, but...
Neither copy was as an original. Main problems are those Peter mentioned. More compressed and less high frequency extension. And more dry and more aggressive. However, many copies are quite acceptable quality and quite listenable. Interesting, but I can not say there were differences between the readers/burners. Neither change of the speed do much of anything. On-the-fly (+ real-time copy) surely doesn’t reduce the difference between the original and the copy. The only way to influence the sound I found is usage of EAC. It makes the copy not to sound dry and aggressive, but also there is an obvious loss at the upper treble. EAC have this effect as extracting, just as the burning software.
And in whole this story, I don’t see a reason why copies couldn’t be “bit identical” to originals. Of course if you don’t make some error and cd is not damaged. How computers could work if copies couldn’t be a “bit identical”?
I just checked two wav files extracted from one audio cd. One is extracted with EAC, the second with AudioCatalyst. They are practically the same. Just a few different characters in the starts of the files. From the expirience I know the files extracted in EAC and AudioCatalyst do sound different. So, it will be very interesting to learn some day what is the point here.
Pedja
p.s.: Johan, you paid 30K$ for DAC and came to diy area? Maybe you will copy CDs because originals are expensive?
Pedja said:
Hmm, interesting - I need to find a way to tell if a burnt CD causes more read errors.
p.s.: Johan, you paid 30K$ for DAC and came to diy area? Maybe you will copy CDs because originals are expensive?
Why not ?
I'm mainly interested in building loudspeakers since I do not have any tools or time to do electronics constructions.
DIY is for me more fun than to buy it from a store.
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