ChatterBank5 mins ago
CD quality.
4 Answers
I remember a friend of mine in the 1980s having one of the first CD discs and a player which cost a hell of a lot of money at the time. He showed me that he could scratch the disc and it would still play perfect. He had a spare disc which he did scratch with a piece of sandpaper and it did play without any sound deteriation.
Why do the CDs these days jump if there is just a thumb print on them?
Does this have anything to do with the discs or does it mean that the players laser pick-ups are inferior to what they were? Or both???
I have an old Japanese CD disc here from 1988 and it`s really thick and heavy compared to todays pressings.
Why do the CDs these days jump if there is just a thumb print on them?
Does this have anything to do with the discs or does it mean that the players laser pick-ups are inferior to what they were? Or both???
I have an old Japanese CD disc here from 1988 and it`s really thick and heavy compared to todays pressings.
Answers
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What a great question, I was only speaking about the same thing a few weeks ago. I also remember a friend having one in the eighties. They seemed to be the follow on from the not very popular video disc players. The adverts at the time stated that you could 'eat you dinner off them'.
You are right in saying that they are much thinner nowadays and jump if they have a thumbprint on them.
Unless you pay premium prices nothing lasts nowadays. If you buy a washing machine you will be lucky to get a couple of years out of it. On several occasions I have looked for spare parts on the web. Most of the time there is no point because they cost nearly the same as the origional product.
Going back to the cd's, a pack of 100 can be bought from any major supermarket for about a tenner. You use them, scratch them, throw them away.
Its the throw away society we live in today.
You are right in saying that they are much thinner nowadays and jump if they have a thumbprint on them.
Unless you pay premium prices nothing lasts nowadays. If you buy a washing machine you will be lucky to get a couple of years out of it. On several occasions I have looked for spare parts on the web. Most of the time there is no point because they cost nearly the same as the origional product.
Going back to the cd's, a pack of 100 can be bought from any major supermarket for about a tenner. You use them, scratch them, throw them away.
Its the throw away society we live in today.
I agree. I remember a course tutor using a marker pen to black out an eighth section of a disc and it still played on budget cd player.
I find if I have a scratched CD it's more likely to play properly on a dvd player !
I think in the early days the cd players had more buffer memory but that would be a guess.
I find if I have a scratched CD it's more likely to play properly on a dvd player !
I think in the early days the cd players had more buffer memory but that would be a guess.
CDs most defiantly have not got thinner, the thickness of a CD is set out very precisely by, initially the yellow book standard, and subsequently by ECMA-130 at 1.2mm thick. any thicker or thinner than this and the disk would simply not work.
The same standards also very closely define the material the disk is made from (for the information area) and most other physical properties and have done since the early 80's
The same standards also very closely define the material the disk is made from (for the information area) and most other physical properties and have done since the early 80's
Most "defiantly" got thinner? Who was insisting that they stayed thick? LOL.
I remember one test when CDs arrived where a 1/8th inch hole was drilled in a CD yet it still played. In music players they do fill in missing bytes by interpolation. This would not work in an MP3 file on a disk because the compression already cuts it to the bones.
Part of the change in perfomance is no doubt that they realised a disk that never failed would never need to be replaced. Player hardware is also much lower quality. I have an ancient Sony player that will play disks that don't work in a modern player.
One of the biggest factors is the thickness and integrity of the reflective coating of the disk. The disk thicknees has a minimum limit and the coating is about the last place that cost can be cut.
I have seen CDR disks held up to the light that allow the light souce to be seen clearly through them. This is the best test of disk quality that I know. A colleague once repaired an unreadable disk by spray painting the label side to make it reflect better.
Floppy disks went throught same degradation. Early disks were quite reliable but toward the end you were lucky to get your files back of them after a few uses.
I remember one test when CDs arrived where a 1/8th inch hole was drilled in a CD yet it still played. In music players they do fill in missing bytes by interpolation. This would not work in an MP3 file on a disk because the compression already cuts it to the bones.
Part of the change in perfomance is no doubt that they realised a disk that never failed would never need to be replaced. Player hardware is also much lower quality. I have an ancient Sony player that will play disks that don't work in a modern player.
One of the biggest factors is the thickness and integrity of the reflective coating of the disk. The disk thicknees has a minimum limit and the coating is about the last place that cost can be cut.
I have seen CDR disks held up to the light that allow the light souce to be seen clearly through them. This is the best test of disk quality that I know. A colleague once repaired an unreadable disk by spray painting the label side to make it reflect better.
Floppy disks went throught same degradation. Early disks were quite reliable but toward the end you were lucky to get your files back of them after a few uses.
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