While I was checking out the Jimi Hendrix CD's on Ebay, I again noticed the VERY expensive SHM (Super high material) limited edition CD's of some of Jimi's standard releases.

What I have found out about them is this: They are a JVC, Victor/Universal music Japan product, made out of Polycarbonate Plastic. This is said to provide enhanced audio quality, thru improved transparency.

Because the Discs I have seen are the limited edition Hendrix releases, I was interested. I am curious, if anyone here has tried ANY SHM-CD release, or read anything about them. If so, any sonic benefits?

If the Mastering is the same, I'd say save your money. A "1" is a "1" and a "0" is a "0" no matter what type of plastic it's sitting on.....

Larry, I'd only read some passing mention of SHM-CDs, but I took some time now to read a bit more. The bottom line from what was read is that it appears to be complete BS. The claim is that it has a new polycarbonate that features "...improved transparency...allowing for more accurate reading of CD data...". Of course, all digital audio and video discs are of polycarbonate construction, using polymers formed from monomers linked with carbonate groups. One of the characteristics of the polycarbonates which makes them suitable for this purpose is their very high transparency, comparable to glass, and I've never before read even a suggestion that even higher transparency would be useful. The laser beam just has to be able to see the point where the disc changes from one level to another, e.g., from a land to a pit or vice-versa(which is read as a digital 1), elsewhere the level part is read as a digital 0. There's no transparency problem and no subtle variations of 1 and 0 that would be subject to a "more accurate reading".

Of course, as Mark mentions, many CDs might possibly benefit from remixing/remastering and exhibit improved sound, but this is an entirely different matter from claiming a fictitious benefit from modifying the polymer.

Now if you put some green marker on the edges, you now have green 0s and 1s.
Clearly that makes the sound more rich, because the colour of money is green therefore the 0s and 1s must be richer.

No really, i'm not joking.

JohnK,

I knew I could count on you...AND, I agree with your analysis.
I thought the only problem with the materials in a CD is the potential for Aluminum oxidzing, causing reflection problems.(hence, the 24k Gold discs). The "more transparent" polycarbonate theory, is not logical to me. At first read, I thought perhaps, it was like the old LP days..."virgin vinyl", and so-many grain vinyl, etc, to deliver
higher fidelity.

Larry

Ripp your CDs to FLAC. Store the CDs to never scratch them. Back up your hard drive because it too can wear out or fail. As PC storage continues to improve, your music should be immortal.