Are CDs getting thinner ?

My home cd player has no puck, but I have noticed quite a few newer cds that seem to be thinner than my older ones. Some of the floppier discs won't track in my car cd player.

Not sure what the industry standard is for cd thickness, but I bet there is one.

jay

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Not sure what the industry standard is for cd thickness, but I bet there is one

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I believe the red book standard is 1.5mm +/-0.3mm. Sad really, but such numbers stick in my mind...

Then, maybe some CDs do not strictly comply...

Look thinner, sound thinner - it's all getting very shoddy.

Or maybe I'm buying the wrong CDs?

Is it my imagination or have most of the people who used to know how to produce and engineer good quality recordings retired or died?

I seem to be stuck in the 80s-90s for want of something which isn't compressed and full of distortion - although of course, there are always exceptions - thank goodness. I just wish there were more of them.

Cheers

Harry

I think the thinner CDs started with the classical releases on the RCA label. If you look at the coded imprints very closely with a scanning electron microscope, you will find the words 'Dynapit'microengraved there.


Ron
Dum spiro audio
Dum audio vivo

New vinyl seems to be getting thicker.

Are we going to fall for it again ?

Yes Probably. On this Forum perhaps not. But to the great record buying public almost certainly. The only ray of light on the horizon for me is that the so called digital "revolution" could mean more and more incompatible new formats, multi speaker etc and that it could be seen by the great multitudes as a big rip off to get you to buy more and more speakers/amplifier combos and inherent conservatism and parsimony may just kick in and put a stop to it. Any views on this?

Yours in Music

Syd

Ron
Dont have a scanning electron microscope in the garage but I do have a micrometer and FWIW:
Miles Davis KOB mastersound gold thing 1.13mm
FZ stictly commercial 1.14mm
Robert Plant fate of nations 1.15mm
Joni Mitchell don juan...1.16
Ansemet conducts Rimsky-Korsakov 1.20mm
Coldplay a rush of blood......1.21mm
Bruce Springsteen tunnel of love 1.17
Naim Audio sampler two 1.20mm
Antonio Forcione dedicato 1.23mm
Cheers
Martin

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Originally posted by Alan Ball:

Are we going to fall for it again ?

-A-

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I hope not, i still haven't completed my re-buying from the first go around..the wife won't like this one bit..

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Originally posted by Martin D:
Ron
Dont have a scanning electron microscope in the garage but I do have a micrometer and FWIW:
Miles Davis KOB mastersound gold thing 1.13mm
FZ stictly commercial 1.14mm
Robert Plant fate of nations 1.15mm
Joni Mitchell don juan...1.16
Ansemet conducts Rimsky-Korsakov 1.20mm
Coldplay a rush of blood......1.21mm
Bruce Springsteen tunnel of love 1.17
Naim Audio sampler two 1.20mm
Antonio Forcione dedicato 1.23mm
Cheers
Martin

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Very interesting, and if JeremyBs measurements are accurate ie. 1.5mm +/-0.3mm then a lot of manufacturing plants are not making CDs to the redbook standard. Anybody know where we can find the Redbook Standard on the web?

Yours in Music

Syd

Martin,

Did the 1.13mm disk slip ? I'm afraid I don't have a micrometer available to check my slipping CDs. What is the threshold at which CDs spin in Naim CDPs ?

Paul

Correction!

Sorry, I must have been thinking of a different disc :-) The standard is 1.2mm +0.3mm, -0.1.

I believe the disk was original stamped from a 1.2mm thick material and then coated with 0.1mm lacquer, I guess everyone got good at reducing all the materials to a minimum and saved $$$.

We can perhaps take heart from the fact that despite having it rammed down out throats, DAT didn't get accepted into every home in the world.

Mini Disk has also not replaced the CD, although it has found its own niche and MP3 players have ended up as personal and in car appliances.

I think the evil stuidos and record companies - the real bas***ds at work here, have too much to lose by depriving people like us of the CD format.

Here's hoping anyway.

Cheers

Harry

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We can perhaps take heart from the fact that despite having it rammed down out throats, DAT didn't get accepted into every home in the world.

Mini Disk has also not replaced the CD, although it has found its own niche and MP3 players have ended up as personal and in car appliances.

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DAT had readily identifiable cost / useability issues that all linear tape-based systems exhibit (hence the total failure of DCC - remember that?). DAT was worse, since it used helical scanning, with it's inherent cost issues.

Minidisc has brought rewards to Sony's faith that it was by far the better system compared to DCC and brings the useability / random access benefits of CD to a portable medium, and sounds better and way more consistent than every tape-based Walkman except the two Sony 'pro' models.

It has resolutely failed as a pre-recorded medium though, there's no huge high-street support for such material. Sony have cleverly attached it to the mp3 market now, with netMD, once again showing their very forward-thinking approach to such things and the market they are intended for.

I doubt the thickness of a CD, within the limits mentioned here, has any audible impact on the sound, although if the disc starts to flex, it would.

Andy.

If you change the thickness of the playing surface of a CD without changing the refractive index of the material then you will affect the focussing ability of the player. In general a thicker disc will be better since the laser beam will enter through a larger area and be less sensitive to surface contamination. Probably.

Paul

Harry wrote:

"I seem to be stuck in the 80s-90s for want of something which isn't compressed and full of distortion - although of course, there are always exceptions - thank goodness. I just wish there were more of them."

Agree!

Except I'm stuck in the 60s-70s for the same reason.

C Koster wrote:

"The most depressing thing about the quality of compact discs for me is the fact that so many are printed off center"

Nothing new here either, they done it to vinyl for ages! Strangely enough it's not particulary disturbing as long as it's not TO much.

JohanR

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Originally posted by JohanR:
Nothing new here either, they done it to vinyl for ages! Strangely enough it's not particulary disturbing as long as it's not TO much.

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Try telling that to my copy of the BBC TV "Loved up" - Hardfloor's Acperience has this very stable synth all the way through on CD - but the vinyl (acquired recently - rarer even than the CD!) has audible wow due to the off-centreness...

I think a lot of the noise from CDP servos you're hearing is due to disc wobble as well - Pioneer stable platter machines are FAR quieter than any other mech I've used in this regard (never used TEAC's VRDS though admittedly) - but yeah, tolerances can be way off - all that servo movement has got to be interfering with the sound - either through poor data or power interference...

When the music's over turn out the lights

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If you change the thickness of the playing surface of a CD without changing the refractive index of the material then you will affect the focussing ability of the player. In general a thicker disc will be better since the laser beam will enter through a larger area and be less sensitive to surface contamination. Probably.

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I would expect the focussing ability of the lens to cope with these minor variations easily.

In the early days of CDP's some mechanisms had a mechanical adjustment to ensure the laser is perpendicular to the disc.

To set this up a defined, warped CD was used and the mechanism adjusted for minimal amplitude variation in the RF eye pattern from the disc.

The variation here would have been greater than the effect of changes in material thickness I'd expect.

The focussing range of modern drive doesn't seem to be any less, AFAICT.

Andy.

AFACIT the reported thicknesses here aren't outside the expected range, so we don't actually have any evidence of thin CDs.

Perhaps somebody could try grinding a CD down to a significant thinnerness and see if it still plays?

My book shows a cone of light at 27 degrees in the air and 17 degrees in the disc ending up in a 1.2um spot, at the disc surface it is 0.7mm across. I'm amazed it works at all...

PAul