Do CD's degrade with age?

[trashyrich1157]

I was just wondering if they get worse with age, I have a few that when I listen to them in my truck , I have to turn the volume up 4 or 5 clicks compared to some newer ones.

any thoughts?

[russ69]

No but the inside of a car can get pretty extreme, temps up to 140 and the sunlight can really do a job on most plastics. They still do better than a LP!

Thanx, Russ

[Islander]

Many newer CDs, particularly ones made in the last five years, are recorded at much higher levels than older CDs, at the cost of much more distortion. If you Google for "loudness wars", you'll find out what I mean. There's also been some discussion here on the forum about that very subject.

[JJkizak]

I have new/loud and old/not so loud CD's and I hear no difference in distortion.

JJK

[Joe Shmoe]

It has to do with ever changing technology. Alot of older CD's don't sound as good or as loud because when they were recorded/mastered back then the equipment wasn't as good as it can be today. That's why you have alot of bands/musicians re-releasing their catalogs in "remastered" versions.

I think the distortion problem comes in when bands try to compete with the higher bitrates of MP3's, Metallica's latest release is a good example of this.

[WMcD]

There seem to be many issues.

Yes, CD's degrade to the extent the data bits can not be read.

1) This is because the plastic surface becomes scratched and the laser and opticial photocell can't read the data (like you have a dirty set of glasses). You can see this just by looking at the undersurface. Cleaning can help.

Or 2) the aluminum backing corrodes. This is somewhat an argument for the disks with a gold surface. You can see the effect of this by holding a CD up to light, i.e. putting the label side, or the other side toward the light. You may see pinholes.

The inability of the optical system to read data just causes the skipping and repeating. Or the player freezes. (When my DVD player quits and gives a message "the disk is dirty" I always tell it that PG-13 is not dirty. Smile.)

But the question is whether a damaged disk will play back but with low level of audio. The answer is no, from the best that I can tell technically, and by my own experience. And conversely, if the level seems to be low, "Is that from damage to the disk?" No, again.

As described by others above, more recent "pop" recordings tend to be highly compressed in the mix just before they get sent to the equivalent of the CD burner. You might be experiencing that. (This went on with vinyl too even in the early days.)

There might be some notion that a damaged disk just happens to be missing the bits which lead to high output. Obviously damage can't happen only to all the "loud bits" at random.

Further, the CD format is very complicated with a Reed-Solomon interleave coding. (Too much to explain here. Meaning, I don't understand it either.)

But re R-S. The data stream is broken up into blocks of data describing the level in time. What is recorded is that block (first block) but also another block (second block) is recorded too; describing the frequency spectrum (Fourier transform) of the first block of data. These two have redundant information, in a way.

This is different than just sending the same signal encoded the same way, twice. That would be simple. We could compare the first block of data to the second and if they are not identical, they we know there is a problem. And this assumes the same exact error does not occur in the two blocks. We've got a problem that the two blocks are not the same, but where is the error? We can't go back to the source and ask for another transmission.

Apparently this is the magic of the R-S interleave coding. We've got the data in time and the data's frequency components too. By a lot of math, these two data can be used to reconstruct the orignal data because it is encoded in two different ways and "missing bits" damage to either is not possibily affecting the missing data in both the real time block and the frequency response block the same way. So the little internal computer of the play back unit figures this all out.

The fall back is is when a data block is too messed up for help and recalculation. The little computer has memorized the level of the blocks before and the blocks after. It says, I'll just make the missing block the average of the one before and the one after. This is interpolation.

- - - -

Even though the above is very complicated, it does not mean that a damaged CD is going to play at a lower level. Rather, it prevents it.

Best,

Wm McD

[Guest " "]

Older CD'shad a 3 digit leter code on the labels. The lowest dynamic range were coded AAD. AAD meant that an analog souce was analog mastered and then ditigally pressed to a CD. The highest dynamic range were DDD. DDD meant that a ditigal source was ditigally mastered and pressed to a CD.

The point of these codes is that today, you don't see DDD, AAD, ADD codes anymore. Makes me think that all CD's are now ditigally recorded, mastered, and pressed to CD.

So, comparing an older AAD, or ADD to todays probable DDD's could be what the issue really is. The newer ones sound better becuase they are.

[Don Richard]

Factory disks do not degrade, per se, but may become physically damaged. CD/Rs, however, may degrade over time, although I have not personally seen any that have. Yet.

[Jay481985]

cd-r and whatever use organic dyes that a laser burns information onto which degrades

real cds are pressed, meaning they never lose the information.

The plastic can though become an issue.

[Schu]

In the older days... the metalics were known to oxidize. this was a major concern in some Laser Disks

[nola]

A few yrs back when trying to figure out which kind of CD and DVD blanks to buy, there were many "computer geek" type postings. Huge differences were pointed out, many lead back to the actual maker of the CD or DVD blank, regardless of whose name was later imprinted on it. Much like wafting thru info on Flash drives, memory chips, etc. Rewritable media uniformly flunks out with significant data loss expected with age (even days) or multiple uses. I do not know what standards are in place, if any, regarding heat tolerance. I assume there is good heat tolerance, but some data loss is likely to be expected esp if the aluminum data pits can be damaged by 100 degree heat - and I don't think car in the sun heat can do this. If you find some "old timers" that use M&K gear, they might be formerly employed from recording studios, etc, and might know.

However, I have no idea what standards, if any, most major music CD / DVD makers adhere to. There might be actual, true and verifyable info available via the archivists at the Library of Congress, or similar government labs in Canada, UK, etc. I know the LOC does have info available on preserving records and other recordings. My guess is that data on properly stored CDs or DVDs might have a 25 plus yr shelf life. Lots of assumptions here. Most members of this forum have 20 yr old CDs that are fine. However, does anyone really expect CDs or DVDs to be the storage method of choice for much longer? Anybody still use 1.44 MB floppys or 3.5s, etc, anymore - do you even have readers for these anymore?

[Schu]

I regulalry still use a 1.44... but I have a unique situation. Point was well taken though as OWNING a physical item will soon be outside of market norm

[Andy W]

People (recording studios) used to respect the limits of digital recording, but no longer, especially music intended for radio listening.

Now everything is compressed to about 3dB of dynamic range.

And they wonder why "old" people stopped buying CD's...

Not to mention the music just pretty much stinks.

[Jay481985]

Yes, all these kids and their "rap music"!

Eh we listen to the music of our generation, it is how it works. Just our generation is mp3 now........