Recording media - http://www.straightdope.com/columns/020816.html

[coolestwhiteboy]

If microfilm is itty bitty recording stuff, can large or very large messages be considered "macrofilm"?

[dantheman]

Do CDs have a life expectancy of 10 years? (http://www.straightdope.com/columns/020816.html)

[Probably better if the link is in the message...]

[Leslie Gerber]

I'm a classical record dealer (LP & CD) and publisher in both formats with 32 years of experience, just to set my credentials on this subject straight. There were actually two producers of defective CDs which have oxidized, Optimes in Italy (which made the Italian bootlegs and many other Italian discs) and PDO (a branch of Philips) in the U.K. The latter produced many thousands of defective classical CDs, which it has been replacing with new discs even if the originals are out of print. Cecil's emphisis on playback equipment is certainly justified, although you can still buy new LP turntables and cartridges if you look hard enough for them. CDs have automatically received an extension of their lifespan since they are backwards-compatable with DVDs; that is, a DVD player can play almost any CD. But eventually DVD will go away too. Still, with so many CDs and DVDs out there, it seems impossible that finding a player will become impossible within our lifetimes.

[Don H.]

Originally posted by Leslie Gerber
Still, with so many CDs and DVDs out there, it seems impossible that finding a player will become impossible within our lifetimes.

That's what they said about LPs when CDs were first out.

[Shifty]

Record companies themselves transfer master recordings to new media. Even if the companies don't _release_ every title on retail CD's, they may still have the original master and the original equipment, plus the equipment to move the music from the master tape to master digital tape to master digital computer file and so on.

Also, there's the access issue. The web makes it a lot easier now to find a recording than ever before, despite CDs v. tape v. LP's v. 78s v. wax cylinders v. player piano rolls. And you can still buy/borrow equipment to play all of these, somewhere. Once you play a recording once, you just record it on a more modern medium, and digitize the recording so you can record it again to an even newer medium.

The longevity of CDs is less important than whether the music (or whatever) on them gets placed on a new medium and lives on.

[BobT]

I think the Oral Tradition is best. I shall just pass on all information I know to future generations in this way exclusively from now on.

[coolestwhiteboy]

Shifty--

The problem with digital recording, of course, is that certain nuances characteristic of the original analog recording (tape or vinyl or wax cylinder) may be lost, though newer technology is getting closer to capturing those nuances.

Smartypants

[Musicat]

With regard to Cecil's statement It's now recognized that tape degrades after 20 years, maybe sooner,..., in my experience, this is far from gospel. I recently have begun to copy old open-real 1/4" audio tapes and 30-year old cassettes to digital storage, and have found considerable differences in longevity, not directly related to age.

I have some 50 year-old open-real, acetate and polyester-backed 1/4" tapes that appear to be perfect. They are flexible, not flaking in the slightest, not cupped or otherwise damaged and they play just fine in a Teac recorder.

But I have some 30-year old tapes that won't play for 30 seconds without gumming up every surface they touch. And this is name-brand, studio-quality media (typically Ampex 406).

So I think that anyone who makes a statement as Cecil quoted is probably doing what the blind men did while examining the elephant -- taking a sample of one batch and ascribing the discovered characteristics found to all other batches.

Same thing with the "CD rot" story.

And in case you're wondering, all my media has been stored in similar environments, (not carefully controlled, but "room temperature/humidity") so that is probably not a major factor in longevity.

Addendum: Sometimes the deterioration is not the "data-surface" of the tape, but oils in the backing causing capstan slipping, or pressure pads in cassettes that harden. Pressure pads can be replaced, but I haven't found a solution to the oily or sticky backing problem.

[MootheMagicCow]

I don't know about you guys, but CDs seem to get worn out in no time at all. Myself and others I know have played CDs to the point where they easily skip on any stereo. Saying a CD will last for 100 years is garbage. It may survive, but would the songs?

[Princhester]

I'm with Shifty. The big point Cecil does not mention is that once something is digitized, it can be transferred easily to whatever other digital storage with no loss of quality whatsoever, unlike an analogue medium which loses data and gains new noise each time you re-record it onto a new medium.

Precisely the same digital data could be swapped from a current cd to whatever becomes the latest medium time and time again for the next millenia with no loss of quality.

And I can't say I think much of the Rosetta Stone analogy. The Scientific American article (and Cecil) suggest that it is not the longevity of the medium but the redundancy of the equipment to read it that tends to limit a technology's lifetime. They compare how comparatively easy it was for the world's top linguists and historians to decipher the Rosetta stone, with how hard it might be for your average Joe Blow to decipher an 8 inch floppy.

Not fair at all.

A fair analogy would be comparison of the former (deciphering the Rosetta by the world's top linguists and historians) with how easy it might be for the same calibre of experts to decipher a cd in the year 4002. Do you think they would fail if the CD were still intact? I don't think so. Particularly if the CD was encoded in three different languages, one of which was still known to some extent (as for the Rosetta).

If anything would stop them it would not be the lack of ability to make the equipment to read the CD, it would be the deterioration of the CD itself.

[Musicat]

Originally posted by MootheMagicCow
I don't know about you guys, but CDs seem to get worn out in no time at all. Myself and others I know have played CDs to the point where they easily skip on any stereo. Saying a CD will last for 100 years is garbage. It may survive, but would the songs?
If your player is operating properly, I doubt if the playing of CDs is what is wearing them out. Unlike a record or tape, there is no physical contact between the media and the "data pickup" mechanism. You could play a single CD continuously for years and there would be zero wear.

Most likely your problems are caused by improper handling of CDs when they are not being played. Stacking them on top of each other, leaving them around on the table, putting them in cases where they have to slide past a relatively abrasive substance, not to mention your hands and fingers -- all these introduce scratches, smears and other defacement. A laser beam is tame by comparison.

[saoirse]

Originally posted by Princhester
A fair analogy would be comparison of the former (deciphering the Rosetta by the world's top linguists and historians) with how easy it might be for the same calibre of experts to decipher a cd in the year 4002. Do you think they would fail if the CD were still intact? I don't think so. Particularly if the CD was encoded in three different languages, one of which was still known to some extent (as for the Rosetta).

If anything would stop them it would not be the lack of ability to make the equipment to read the CD, it would be the deterioration of the CD itself.

I think it's more a question of the transparency of the technology. Our future scientists in 4002 would have to somehow intuit that, say, this little disc with a picture of four guys on it is actually a device to store the music that those four guys made. I don't know how they would come to that conculsion without knowing what a CD was.

[Princhester]

They would look at it under a microscope. They would find regular series of pits. They would try the hypothesis that the pits represented digital data, and it would flow from there.

You underestimate human ingenuity and curiosity, IMHO.

[partyofone]

As to the original question, I just happne to have spent the weekend researching a similar subject and ran across a CD supplier's page on CD reliability.

The page, which I didn't bookmark, talks about the 10 yr life in terms of a specific benchmark of 50 read errors. Based on their analysis of aging of CD in a dark enclosure, but otherwise subjected to thermal cycling, they get a 10 yr life based on their benchmark.

Furthermore, they point out specifically that the CD is readable well beyond 50 errors. If you think about the CRC error correction, it can probably handle hundreds and possibly thousands of read errors before the CRC fails to correct a single error. Which means that CD's can be usefully read well beyond 10 yrs.

This means that unless you have a CD player than can give you bakc the number of read errors from an old CD, you really can't say if it is actually meeting its 50 errors after 10 yrs requirement.

TTFN

[CurtC]

coolestwhiteboy wrote:
The problem with digital recording, of course, is that certain nuances characteristic of the original analog recording (tape or vinyl or wax cylinder) may be lost, though newer technology is getting closer to capturing those nuances.

What nuances are you talking about?

[Biffy the Elephant Shrew]

Originally posted by Musicat
With regard to Cecil's statement , in my experience, this is far from gospel. I recently have begun to copy old open-real 1/4" audio tapes and 30-year old cassettes to digital storage, and have found considerable differences in longevity, not directly related to age.

I have some 50 year-old open-real, acetate and polyester-backed 1/4" tapes that appear to be perfect. They are flexible, not flaking in the slightest, not cupped or otherwise damaged and they play just fine in a Teac recorder.

But I have some 30-year old tapes that won't play for 30 seconds without gumming up every surface they touch. And this is name-brand, studio-quality media (typically Ampex 406).


That's because the tape formulations changed. Studio tapes from the 1970s are notorious for having turned into goo by now, requiring them to be baked before they can be transferred to another medium. Older tapes used binders that turned out to have better longevity. That's progress for you.

[Musicat]

SOME tapes from my 70's collection have turned to near-goo. MOST from the same era, even some with the same brand & version number are in fine shape.


So not all manufacturers produced short-lived media. But I do recall buying a case of 1/4" pancakes (big, bulk tape with no reels) and brand new, out of the box, they started to shed. I couldn't get two minutes of recording out of them. The manufacturer's rep (and I can't recall the manufacturer's name, but it was something like A***x), came to see me, took the entire box, and offered me another free. I declined, and took the refund instead.

Maybe this was the start of the goo-batch and I caught it just in time.

[parkerea]

Originally posted by coolestwhiteboy
The problem with digital recording, of course, is that certain nuances characteristic of the original analog recording ... may be lost

IMHO, what many call "nuances, " others would call "flaws."

(Total off-topic digression here down…)

I wonder what the result of the following test would be:
1) Take a well recorded LP and dub it to CD.
2) Take a similarly well recorded CD and dub it to LP.
3) Compare all four: the original LP, the original CD, the dubbed CD, and the dubbed LP.

My suspicion is three of the four cases would end up sounding essentially the same: like an LP. I believe the "LP sound" is not due to any superiority of the recording medium, but is in reality an artifact, and many mistakenly attribute the audible difference to the LP's quality. Like it or not, psychoacoustics are a powerful manipulator of our sense of hearing.

Does anyone know of a decent double-blind LP / CD comparison using trained ears?

BTW, I have over 300 LPs, yet am a CD devotee.

[sublemon]

Originally posted by Leslie Gerber
you can still buy new LP turntables and cartridges if you look hard enough for them.

Actually, there are probably more high quality turntables in production now than ever before. There may not be as many cheap or budget components as in the days before CD, but for anywhere from $500 to $50,000 you can buy an excellent turntable. Some manufacturers include VPI, Rega, Michell, Acoustic Signature, Music Hall, ClearAudio, Basis, Nottingham, etc. In the high-end, vinyl is still thriving. And on a quality system, it really does sound better than CD.

[Chronos]

Quoth Princhester:I'm with Shifty. The big point Cecil does not mention is that once something is digitized, it can be transferred easily to whatever other digital storage with no loss of quality whatsoever, unlike an analogue medium which loses data and gains new noise each time you re-record it onto a new medium.Don't be so confident. Back at my undergrad Alma Mater, the astronomy department had rooms filled floor to ceiling with old data. Paper tape, to be precise, with the data encoded in punched holes. It's digital data, to be sure, and a few of the devices to read it might even still be sitting around in museums. Someday, maybe, there will be an effort to transfer it over to a more modern medium. More likely, though, by the time that happens, either the tapes or the machines to read them will have deteriorated to the point of unusability.

[Musicat]

And let Chronos' experience be a lesson to us all.

During the transition overlap from one media to another, there are ample opportunities to transfer from the old to the new. But after a time, that becomes more difficult.

I have some files on 8" floppy that would have been easy to transfer to 5" or other media at one time. Now that is next-to-unpossible. If only we could see ahead to the obvious!

[Leospace]

I have a stainless steel wire recorder my dad used. The media seems permanent. The magnetic field probably decays slowly due to cosmic rays, but certainly very slowly. The sound is as good as ever, even from recordings from the 40's.
What did my dad consider important enough to put on this media?
Lawrence Welk shows.
Sigh.
Oh, I do have a report from a deer camp from one year. Waiting in line to use the ferry across the Mackinac Straits to get to the Upper Penninsula.
And a speech by a labor organizer trying to organize a farming cooperative.
But about 8 hours of Lawrence Welk.

[Markar]

I used to work for a company that put digital data onto audio format CD's (red book audio). We ran into all sorts of problems doing this, and, by necessity, became somewhat expert in CD data encoding. What we found was that there are a suprising number of errors that occur in reading even a well-preserved disc, often going beyond the capability of the built-in error correction algorithms to correct. Most of the time you don't notice this when you are listening to music because the default action is to average between the last two good values that were decoded. For most music, you won't notice this missing (and clumsily replaced) data unless you are paying very close attention.

We found that light and heat caused a very noticable degradation in the data, particularly for rewritable discs. We could make a CD-RW pretty much unplayable by leaving it on a desk in the sunlight for a week or so. These discs didn't get hot, just warm. Maybe they have changed the formulation of the average CD-RW since then, but my suggestion is to keep any CD with data you can't easily replace out of the sun. And don't count on any CD-RW lasting longer than 5 or 10 years, even in perfect climate-controlled storage.

Stamped CD's are substantially hardier, but you are still vulnerable to variations in transparency and delamination over time. The long-term stability of the plastic and the plastic-metal interface has not been proven. And, as has been mentioned above, variations in the plastic formulation will probably yield variations in longevity.

On the sub-thread of nuances lost in the digital conversion, this is a well-researched subject which is very well understood. Digital sampling at 44 kHz is audibly different from high-quality analog recordings. The reasons are easy to understand, and easily available elsewhere, so I won't bore you with the details unless someone provokes me with more talk of psycho-acoustics and double-blind tests.

[li'l Dickie Dirtz]

Originally posted by Princhester:
They would look at it under a microscope. They would find regular series of pits. They would try the hypothesis that the pits represented digital data, and it would flow from there.

You underestimate human ingenuity and curiosity, IMHO.

Indubitably. (http://www.cs.huji.ac.il/~springer/) Not digital, I realize, but still . . .

[Abe]

Originally posted by Markar
On the sub-thread of nuances lost in the digital conversion, this is a well-researched subject which is very well understood. Digital sampling at 44 kHz is audibly different from high-quality analog recordings. The reasons are easy to understand, and easily available elsewhere, so I won't bore you with the details unless someone provokes me with more talk of psycho-acoustics and double-blind tests.

I've always wondered about this question, because a number of musicians (Eric Clapton that I remember off-hand) have claimed that LPs can deliver better quality audio than CDs. Is there somewhere I can educate myself on this topic?