Roger Hecht wrote:

>There may be something contractual involved with the Lyritas.  I'm not
>sure, but I've heard odd things over the years about this.

Perhaps someone can fill me in, but I have somewhere in the back of my
mind that some of their master tapes were lost.

and in a separate message, Len Fehskens wrote:

>At the risk of wandering afield of the subject of music: my understanding
>is that the passage of the stylus actually deforms the groove, due to
>the pressure involved, rather than any heat generated.  This plastic
>deformation is recoverable (the groove slowly returns to its original
>shape) but not if it is further deformed by repeated playing before it
>has had time to fully recover.

As far as I know the pressure is significant, but it is the heat that
makes the surface pliable.  If played quickly a second time, the weight
of the stylus can do significant damage.  A single pass, with a clean
stylus, tracking at relatively small pressure will not significantly
damage a vinyl disc.

>Even at a gram or two of tracking force, the contact patch is so small
>that the pressure (kg/m^2) applied is enormous.

Absolutely, and that pressure causes friction and then heat.  There are
photographs of vinyl discs played many times with no observable wear,
yet discs played repeatedly with no cool down will show significant wear
in a short period of time.

A worn needle, on a single play, can shave the vinyl.

Looking at a groove you can see even under the best of circumstances,
that a needle has a rough ride.

   http://www.up.ac.za/academic/electron/phono.htm

And for storing your digital audio

Labels placed on CDRs will eventually peel and take the reflective surface
with them...most inks will compromise the reflective surface of a CDR.

And for the care and handling of CDs and DVDs

   http://www.itl.nist.gov/div895/carefordisc/index.html

Karl