Are your CDs losing tone as they sit upon your shelf?
mainWe used to be told CDs are indestructible. Now we know they die before you do.
Andrew Powell has been researching for us the mystery of the disintegrating Compact Disc. Here’s his report:
I once thought CDs lasted forever. But it could be that some of them, depending on the particular manufacturing process, actually last *less* time than LPs.
Do you know that Kenneth Gilbert set of the Das Wohltemperierte Clavier on Archiv? The one with Leonardo’s Vitruvian Man on the cover? Well, I took mine out in June after at least 20 years of not touching it. Totally decayed! So I bought a replacement on eBay. Same thing. Then another on Discogs. Same thing.
Which means everybody has this problem, I would bet.
Returned both, got my money back. But what to do next? Abandon the handsome original packaging and excellent documentation? No. But sadly DG only issues the thing now in its Blue series from 2003, which has no graphical relationship with the original set.
In early August I discovered that DG did reissue the set in 2015 in its Collectors Edition series as part of a larger set of ten CDs. Here the graphics were neutral enough to work with the original packaging.
But this series really was a limited edition, and the Gilbert cannot be had in the West for love nor money. Not on eBay, not on any Amazon, not at Gramola in Wien, not at Presto, not at Discogs, not at ArkivMusic in Tennessee, not at Rakuten in Tokyo, not at Dussmann, not at Saturn. New or used. They list it, of course, but it is out of stock. Try for yourself: EAN 0028947942375.
Which reminds us that the record company execs don’t know what they are doing, don’t know their markets or buyers.
The end of the Gilbert/Archiv story for me came today. After paying *€120*, no less, I was able to secure a copy in Moscow through CDandLP in Saint-Étienne. It appears that Russian traders have been buying up those at first cheap DG Collectors Edition boxes and are now profiting from their scarcity. Remember: they were released as recently as 2015!
Such insanity. Well, this copy is shrink-wrapped, so I am happy.
But why are some CDs going bad all by themselves?
Discuss.
This has been known for decades. https://en.wikipedia.org/wiki/Disc_rot
Maybe it has but not everyone would have known or had Wikipedia for decades to refer to as you obviously have had, as some of us haven’t had home computers for decades and CDs only sonce the 90s, certainly not in the UK!
Actually the CD’s which “bronzed” first to my recollection were ones on UK labels like the historical label Pearl which became unusable very quickly. they had to spend a fortune redoing discs for customers whose discs had become redundant.
I just played the first of the 5000 or so discs that I have accumulated since I came late to CD back in 1985, and they are all fine: Bax 4 Thomson, Berlioz Fantastique Abbado Chicago, the Haitink 1982 Bruckner 9 and Rozhdestvensky Shostakovich on JVC. All purchased from Circle Records in Liverpool in that year.
The problem seemed mostly to occur with discs where the reflective surface was silver, rather than the usual aluminium. The idea was that it would be higher quality, unfortunately, it was prone to tarnishing. You sometimes can see this as a golden/bronze discolouration. PDO were the plant that were known for the issue.
I noticed this also. But not all Cd’s , just some of them, probably not produced well enough.
The decay of some CD’s begins with an occasional regular ‘ticking’, just like an LP with a scar, and later-on getting stuck in a repetitive ‘choink’. An excellent box I have with Monteverdi’s Vespers by the Sixteen is now sprinkled with ticking and a degenerated sound, as if microphones have been set in the wrong way. But the CD’s were superb when I got them some 15 eyars ago.
Old LP’s I still have are still as good as ever, apart from an occasional scar.
I spent a lot of money 5 years ago on a high end CD player, amplifier and speakers. Some CDs click, just stop in the middle and the player turns off after about 10 seconds. I contacted the manufacturer (in Denmark) and they wanted me to ship it back, unable to explain why this happened. It has been so frustrating that I play less and less CDs on it now, but I have noticed it’s not only older CDs but some of my more recent purchases. Having read this, I’m now wondering whether it’s the discs and not the player at all.
The quality of CD, DVD, and Blu-Ray “media” and “pressings” has varied wildly over the years. Because of that issue, and also because of risk for scratches damaging the data readability while removing from jackets, or putting into auto-load payer devices, I recommend that such media be backed up – DRM of DVDs and Blu-Rays notwithstanding, some of those things are a nearly unfixable problem.
They are not actually “pressings”, of course. Some are pressed by individual lasers, while others are “pressed” by a chemical lithography process. They are all prone to degradation, although some very expensive discs (writable only once, individually, by laser) have promised a higher lifespan. But I personally prefer to rip them onto “computers”, and backup/copy those computer media libraries fairly frequently. those computers.
The performances, frequently going out-of-print, are kind of like out-of-print books: The ‘Bronstein editions’ of famous violin concertos with great and voluminous teaching comments, published by a certain “Paganinina Publications” in New Jersey, USA is an example of great personal distress to me – I would love to acquire the entire set for considerably less than the current $800-$2000 price of beat-up used copies. No one can make copies, because they could be sued by some invisible “heir”.
Media degradation, DRM, and unreasonable Copyright Laws are killing legendary performances AND significant printed works of great value.
Just send the records to space!
I got my local library (WA state) to get a copy of an obscure piece of music from outside it’s system … perhaps you could get a copy of the Bronsteins this way and … do what you will before returning it?
(Librarians are the best!)
Rickst29: I also recall the Bronstein edition of unaccompanied Bach, which reproduced the music on very large pages. Raphael Bronstein, who taught Elmar Oliviera, Martha Strongin Katz, Daniel Kobialka, and his daughter Arianna Bronne among other fine violinists, had the opinion, which I agree with, that the tightly packed appearance of most editions of unaccompanied Bach creates a psychological learning challenge for students and performers that can be lessened if the pages are big and notes are spacious. The only time I ever saw and played from the edition was on a music stand in a small room at Chicago’s Bein & Fushi violin dealership. Maybe it helped sell fiddles if the customer could suddenly play some Bach better than ever before, and credited the violin rather than the large print of the edition!
I am pretty sure “Paganiniana Publications” was the late Herbert Axelrod, noted violin collector and reputedly very able amateur violinist, who used his fortune made in the tropical fish business to further his interests in the violin, such as publishing the series of Samuel and Sada Applebaum books of interviews with famous violinists, which included at least one interview with Raphael Bronstein, and published Axelrod’s own biography of Heifetz and a reprint of the Lochner biography of Kreisler. He was rich enough not to care if he made money at this.
I do not recall reading of any heirs of Axelrod when he died, more or less in disgrace over tax fraud issues.
I backed up all of mine in FLAC format to a Brennan B2. Only 1,000 or so compared with the 5,000 reported above. It’s not difficult and can be done whilst getting on with the remainder of the day’s chores.
One bizarre puzzle arose with the Werner Jacob set of Bach’s organ music. The box contained all 16 CD sleeves, but not a single CD.
I cannot imagine any circumstances in which I would have removed all 16 from their sleeves.
Suggestions welcome.
An organ transplant?
They didn’t just vanish into thin air: someone took them.
I’ve ripped my ~3,000 CD collection to Apple Lossless, and play them on my stereo system via Apple TV. And the drive that the collection is stored on is backed up locally as well as the cloud (Backblaze). So I feel that my collection is well secured for the rest of my life. Pro tip: the benefit of going to the Apple/iTunes route is that for $25 a year, you can get iTunes Match that lets you stream your whole collection on your phone from iTunes. It’s pretty nifty to always have access to the collection.
“Suggestions welcome.”
Make backups.
And the requisite electronics engineering/computer systems degrees for those who have to do this – or even keep up with or understand the need for it.
Absolutely pass.
“And the requisite electronics engineering/computer systems degrees for those who have to do this – or even keep up with or understand the need for it.
Absolutely pass.”
Erm. Sure. Whatever. 😀
ITunes does it for free, on any Mac you buy, or you can download the download the app on Windows. No doubt there are Windows apps not made by Apple which are similarly capable.
Emaculate disintergration
Well this is one way to deal with the oversized collection, let it rot – then tossing them out won’t be so painful. I did have a number of disks years ago that corroded; most from the UK on the Unicorn or ASV labels. Some Vox disks were bad, too.
I had three CD’s with all the works of Xenakis and after a number of times that I played them, they became fluid and dripped from the cases. When I called the shop they said it was the music and they couldn’t help it.
Sally
Michelin knows how to make tires that last a life time, but they don’t.
Apple knows how to make phones and laptops that last a life time, but they don’t.
Pfizer knows how to make a single shot vaccine that lasts a life time, but they don’t.
DG knows how to make CDs that last a life time, but they don’t.
There is no profit in selling things that last a life time.
There is only profit in re-selling the same thing over and over again.
Time to buy that “booster” CD to that CD you already have.
; )
Excellent comments!! In-built obsolescence is a major feature of the capitalist business model. With that and normal wear and tear you know you’ll be replacing whatever you buy!!
If you find that part of your collection has succumbed to disc rot, check with the publisher to see if they have a replacement policy. As recently as a few years ago, Hyperion would still supply (free of charge) new clean copies to replace old bronzed discs. See https://www.hyperion-records.co.uk/pages/bronzed.asp.
Depends on the CD factory. Stuff that is manufactured cheap from cheap materials doesn’t last
Ten years ago, some fan sent me a CD with recycled music by Tomas Ades on a recycled disc and strange enough, that disc is still in perfect condition.
Maybe the reason is that I only played it once.
I have had cds since 1984. Never had a problem.
Most of my failed discs were either from the former PDO plant – I had them replaced while I had the chance – or 1990s EMI discs. (Curiously, the Artist Profile 2-disc sets were most likely to go bad.) Typically, it’s the final tracks, which play from the outer part of the disc, which go bad first. Having said that: My Strauss Vier Letzte Lieder with Jessye Norman, which I purchased 35 years ago, still plays just fine.
So far, I’ve only had this happen with no-frills freebie copies given to journalists for review purposes. So I do think the manufacturing process or some other aspect of disc production must be relevant.
It primarily affects CDs manufactured for PolyGram by PDO in West Germany during the 1980s.
“It primarily affects CDs manufactured for PolyGram by PDO in West Germany during the 1980s.”
No, that’s bullpucky. PDO in Blackburn (UK) is known for its disc bronzing. Got my ASV discs.
http://www.classical.net/music/guide/society/krs/excerpt3.php
http://www.classical.net/music/guide/defective.php
(Bronzing is a form of disc rot.)
If it’s what I have experienced, I believe it’s called “cd rot”. (If someone knows otherwise, please inform.)I’ve been able to find some replacements and some items were transferred to iTunes. My “rotten” discs were almost exclusively from German/Dutch labels. Hmmm…
It’s a matter of cultureal identity. The German and Dutch culture are famous for being thorough and trustworthy, so they sell the discs with that marketing pitch, but hope you will buy new ones as soon as they rot. Namely, the factories cleverly build-in a time duration, as in light bulbs.
Huh now I finally know why some of my favorite CDs just suddenly stopped playing…they had no scratches so I was ConfuseD.
But if it was the “original packaging and excellent documentation” that was important, why don’t just look at and read from your original CD package while buying and listening to that Blue edition which appears to be readily available?
Because of this risk which has been known for a long time, I spent months digitizing all of my cd’s about 13 years ago. Out of about 2000 cd’s, there were a few that were badly degraded. The streaming services, digital downloads, youtube and my digital collection are enough that I haven’t had the need to buy a cd since.
It’s true that the quality of both factory pressings and CDRs vary in terms of longevity and even audio quality. And let us not forget the humble cassette tape. Just recently, I wished to hear a November 1991 interview I did on Hear and Now, hosted by Julie Lyonn Lieberman and Cynthia Bell on WBAI-FM in Manhattan, the reason being La Monte Young had phoned me after hearing the show leading to a lengthy conversation, and I wished to be reminded what tracks had been played from my first album, Trembling Flowers, because my new album, A Parrot Sipping Tea, apparently represents the first time another composer has used a tuning La Monte invented in 1964 for his Well-Tuned Piano, if adjusting the tunings for 4 of the 12 swaras (tones). Fortunately, I was able to locate the cassette recording made back then, and the sound quality was superb like the show was aired the day before. I was interviewed the first half hour, and Philip Corner the second half of the show. More so for cassettes, when I began my studies of Indian classical music with Harihar Rao, the senior disciple of Ravi Shankar, I discovered how Indian shops here in Los Angeles and Little India (Artesia) sold cassette tapes of various Indian music genres, including classical, for 2 or 3 dollars each. The most sublime artists, including Pandit Jasraj, Shivkumar Sharma, Hariprasad Chaurasia, Ravi Shankar, and others were represented by stellar performances, a genuine treasure trove of sheer musical genius that grew into the hundreds. Music from cassette tapes tended to provide a warm, personal interaction despite whatever limitations of the medium.
http://azuremilesrecords.com/lovingandrerigginglamonteyoungstuning.html
http://azuremilesrecords.com/tremblingflowers/index.html
http://azuremilesrecords.com/aparrotsippingtea.html
“A Parrot Sipping Tea.” I don’t think Joan Sutherland sang that on her recording of Noel Coward songs.
Found the recordings on Apple Music. Looking forward to giving them a listen tonite
I purchased the Kenneth Gilbert “48” CDs when they were first issued. Checked them this evening and all four discs are still playing without a problem.
Some companies (Nimbus, Lyrita, Priory etc) issue recordings on CD-R (burned CDs) and I have often encountered problems, either immediately or after a couple of years. In every case the company has replaced them without charge within a few days.
As you get older, your hearing loses its high frequency response.
Yes, and that’s a terrifying experience for a music-lover. I bought high-end equipment 5 years ago. Too late!!
It happens with everybody, but it has worse consequences for some (e.g. H v Karajan).
Also, your pitch will sink to sometimes a fith lower, which makes all music considerably more sad than intended.
Ah, so that’s why Beverly Sills sounds like Ezio Pinza to me.
I too have some CDs that are decaying – some Hyperion that are turning brown on the label side for example. It becomes an issue if the brown spots show through on the silver playing side. However some CD writers (pc and others) will read them better than the standard hi-fi CD player. There is no real cure – just back them up.
This has been known about for a long time, and I seem to recall was predicted by some during that original euphoria over “perfect sound forever.” I do recall the guy at the record store raving that you could spread peanut butter on CDs and just wipe it off and they’d still play great. Never tried it. Sounds like he might have.
The first hints that this could happen was the fate of those who went out on a limb and bought laser disc movies — those discs that were about the size of an LP but had the silvery look and sheen of CDs. The format was abandoned about the time people learned that the discs were actually kind of fragile and needed to be handled with great care.
But the first real exploration of the topic was the “bronzing” problem that afflicted discs made at the PDO plant in the UK It was a processing error. Worst of all for me, one label that was particularly affected was Pearl which had many wonderful historic reissues of violinists, cellists and such. Another interesting label, with new recordings, was Nuovo Era. They had some excellent HIP recordings as well as Salvatore Accardo Mozart sonatas which are now unlistenable. I think Hyperion also had problems.
I also know from bitter experience that photographs saved on CD-Rs are also prone to an aging process that deteriorates. And as with sound the deterioration is more intrusive than the way an LP ages, with more and more ticks and pops. Some evidence suggests that CDs and CD-Rs stored in plastic cases last longer than those stored in paper sleeves.
But again this is NOT new or news.
Apart from the “rot” & “bronzing” issues referred to in the wikipedia link above a more recent phenomenon is melting foam inserts.
Multi CD boxes, the “fat” ones, not “twofers”, were often padded out with foam inserts between the cd’s. These have tended to degenerate over the years leaving a horrible sticky residue over the discs. For some reason the Polygram/DG foam inserts seem more prone to degenerate than EMI foam inserts. Google something like “cd foam insert melted” & you’ll see what I mean.
The residue is almost impossible to remove, I’ve had to scrap half a dozen box sets of cd’s because of it. My advice is to go through your box sets & throw away any foam inserts you find. They don’t serve any useful purpose – indeed it seems the cd companies stopped using them some time ago!
Thanks for the heads-up on this. We are moving into a new house in February and selling this one; I have all mine packed and in the garage where they will be exposed to heat during the coming summer. I will rescue them immediately, while we still have Spring.
I , too had the same problem with the London/Solti/Culshaw Wagner Ring set. All the foam inserts turned into a gelatenous mass destroying the CDs. I finally found an original undamaged replacement on ebay. Oddly enough, I had the same problem with a pair of Electrovoice microphones. They came in a metal case stuffed with foam with cutouts to form-fit the microphones. The mics had been kept for years in these cases with no severe temperature or humidity changes, and were damaged. Fortunately when I contacted Electrovoice and told them of this problem, they replaced both mics at no charge. This was 20 years ago. I don’t know if this company would be so responsible today even if the problem was initially their fault.
My copy of the original issue of the Gilbert WTC – bought in 1985 – has no decay traces at all and still plays flawless. I have round 10.000 CDs and I experienced this problem only with 4 items in nearly 40 years: Caruso Complete RCA box, Kubelik’s Mathis der Maler (EMI) and two Pearl CDs (Gieseking/Debussy, Sibelius Koussewitsky 2CD set).
I sympathize. I also had the same RCA Complete Caruso set many years ago. I didn’t think RCA (BMG/SONY) would be generous enough to replace this set free of charge knowing how cutthroat the recording has been (and still is) throughout its history. Fortunately at that time I had a friend working at Tower Records who replaced this set for me.
Had same problem with Mathis der Maler and bronzing of Nuova Era cds
The problem of long-term preservation of optical media (CD, DVD, Blu-ray, etc.) has been a concern for archivists almost since the inception of those media.
After the first decade, the multiple vulnerabilities of CD, many of them time-dependent, became evident.
Libraries have struggled with them, and addressed them, ever since.
So the Library of Congress:
https://www.loc.gov/preservation/scientists/projects/cd-r_dvd-r_rw_longevity.html
The British Sound Archive:
https://www.girona.cat/sgdap/docs/lxc10nkrichard%20ranft_english.pdf
et passim:
https://www.nps.gov/museum/publications/conserveogram/19-19.pdf
Strategies for safeguarding have included special optical discs less prone to chemical decay.
But the real safeguard is cheap and simple, for it lies in numbers: duplicating the digital files early and often, to a variety of physical supports, never relying on one kind, one format, and one system only.
This is the real magnificence of digital data files: the complete independence of data from their physical support. Data as structures are immortal; every physical support is ultimately doomed, but the data themselves — the *information* — can be transferred and conserved without loss, as long as intelligent beings are capable of devising methods and devices for their storage and reproduction.
In final analysis, the question is not, How to safeguard this or that physical medium, but: Are we intelligent enough to preserve the information that constitutes our heritage?
Same problem with nitrate film from the first 50 years or so of cinema. Clever preservation platforms have ensured the survival of many, while some have disintegrated completely. I admire the work of an organization like Criterion which subsidizes and markets these wonderful restorations.
Even with these (often digital) film restorations there’s no guarantee they will remain in good condition in perpetuity. It’s an ongoing challenge, the same as it is for CDs.
True.
But:
“…… as long as intelligent beings are capable of devising methods and devices for their storage and reproduction.”
…. is reflecting a hope on the human condition which seems to be on the optimistic side, especially now that it appears that even the reproduction of their own kind is not always a priority of humanity.
None of my CD’S, even the oldest suffered the likes. They are all in fine condition. Recently I bought Beecham’s La Boheme, a second hand of the original edition on cd. I guess it’s age is 40 years and it plays smoothly.
Y’all are NUTZ, I have several thousand CDs of all kinds of music genres since CDs first came out and they’re all perfectly fine…
Did you, immediately prior to posting that insult, play all several thousand to check their “fineness”?
I bought my first CDs in 1984. I haven’t come across an issue with any of them. Some are loaded into two Sony 300 disc players; the balance in their original cases. All’s well.
These wonderful recordings are easily available for download from a number of source and, unlike the discs that you struggled to find and purchase at a high price, the files can be maintained (with back-up) indefinitely without deterioration. Notes, too, can be downloaded or copied from your corrupted disc sets.
The answer is NO. Unless subjected to very hot storage conditions such as the glove compartment of an automobile. Optical disc, like what hospitals use for archives, is an extremely stable medium.
Sorry, not all optical discs are created equal!
It is a source of deep worry for the wokes.
This is, truly, much ado about nothing.
CDs that are known to rot are mostly limited to discs pressed at the PDO UK plant in the late 80’s. The sad thing is that there ARE a number of rare discs that were only ever pressed there, and during this time period. However, the Archiv set mentioned in this article is not one of them. If you can’t find a good copy, you haven’t been looking very hard!
For starters, it was first released in 1984, no? This predates the PDO UK plant entirely. The first run of these discs was probably pressed in West Germany, as were many other Archiv discs I have from the timeperiod. And those Polygram WG discs are always as good as new if cared for, they are perhaps the best pressed CDs ever manufactured. I have many dating back to 1983 when they first started manufacturing CDs.
You are not specific as to what has deteriorated. Is it physical, or audible. If its audible is it something that can be qualified via bench test. Wheres the bench test. Finally is the CD just unplayable. I’ve gone full circle from vinyl collector to CD store owner and collector, back to modern vinyl pressings which compared to the pressings of the 70’s and 80’s are truly awesome. But I must say I have not experienced any CD decay in my collection. They just don’t sound as good as the new modern vinyl pressings.
“You are not specific as to what has deteriorated. Is it physical, or audible.”
Your criticism lacks understanding.
While there can be physical deterioration without an audible impact, the opposite is not possible. I mean, really, how do you think that would work?
I have the Gilbert WTC on Archiv, bought as a new release at the time of issue. All four discs (pressed by Polygram in W Germany) look and sound fine. I also have many CDs going back to 1983 which play without problems. The only CDs to suffer disc rot were some of those produced at the PDO Plant in Blackburn UK during the late 1980s. Many small UK labels used PDO, such as Hyperion, Unicorn, ASV, RPO, etc. A few DG/Decca/Philips titles were also pressed by PDO – particularly reissued discs at mid and budget-price. Often, the faulty discs display discolouration (they turn a bronze/brown colour, rather than silver) on the label side. Sometimes, the writing on the label side can be seen on the playing side – as though the ink used has eaten-into the aluminium. However, some PDO discs, despite showing clear discolouration, will still play perfectly well, while others that show no signs of bronzing do not play. Also, some CD players cope better with corrupted discs than others, due to superior error-correction.
I don’t want to make things unpleasantly simple but Gilbert’s WTC 1 and 2 are on youtube.
Just… ugh.
Who doesn’t like highly compressed audio with everything cut above 16 kHz.
A few websites catalog commercial classical CDs suffering from “CD rot” or “bronzing:
http://www.classical.net/music/guide/defective.php
http://www-personal.umich.edu/~bpl/cdrot.htm
This problem was widely discussed in 2006 when the CD manufacturer Philips & DuPont Optical (PDO) went out of business and stopped replacing rotted CDs.
Some companies will replace defective CDs (https://www.hyperion-records.co.uk/pages/bronzed.asp).
Sometimes you need to know someone; my Complete Caruso Recordings and Complete Rachmaninoff Recordings box sets on BMG were melting away and I got them replaced by writing to a BMG executive I had met at a convention.
APR replaced defective CDs for a while about a decade ago after PDO’s demise, but they may since have stopped – at least that’s what I was told when I wrote them and got replacement CDs.
I had an aunt who suffered terribly from bronzing after she had moved to Australia and she deteriorated as fast as any CD, also greatly influencing the sound quality. My uncle wanted to have a replacement but she objected firmly. It became a family story.
Sally
Are your aunt’s initials “CD”?
My Gilbert set (purchased 1985) is holding up just fine. But those thin foam pads were a mistake, and have deteriorated with the decades, leaving nasty bits of sticky detritus on the discs.
My first CDs that I bought back in 1986 still play perfectly with no decay. Seems like this is an alarmist article about a single CD release with manufacturing defects.
It was a difficult process to develop the CD recording technology. It took years from the first attempts (with large square wooden discs) to the small round format which was presented in the eighties. Also the booklet size was a problem and a Japanese firm offered to provide a small plastic amplifying glass with the booklet but the Sony director at the time protested that the device was meant for ‘a clearsighted and clearhearing audience’.
Also… am I a bad person to say Gilbert’s WTC sounds, today, a little bit like the way they used to play baroque music in the early eighties? We have moved on since then.
Nothing has ever been so bad as the way they played baroque music in the 17th and 18th century.
It may be too much trouble but could you post photos (ideally a flat bed scan) of the inner hub of those CD’s that have gone bad? Just enough to give us all of the pressing info (the mould codes, etc.)
As mentioned below, this has been known for a while, but if you’re having problems with multiple copies of a particular title (especially a particular edition or re-issue), it seems to hint that the problem was with that pressing in general. It may even be the pressing plant that made that CD, and without burying anyone into too many details, there were pressing plants in the 1980s that were notorious for poor quality pressings that would go bad with time (not over the long run, but within several years).
Here’s a new hobby for the long winter nights: rip your collections to HDD/SSD, scan or photograph the covers. Keep the two drives separated from each other, preferably in different houses, if you’re really paranoid about security and theft.
If you really want the Gilbert Well Tempereds then they are found in the Bach 333 Box set with about 220 discs featuring all the Bach bits and bobs popular and arcane…
CDs must be kept in the dark.in a drawer and in their box!