Syd, we might be able to help with that issue since we restore
analogue tapes for various organisations and individuals.
Generally speaking, without going into too much detail, the problem
is typically framed by one of two issues (although there can be
others): Hydrotropism; where humidity was absorbed by the adhesive
medium that held the tiny particles of oxide to the mylar backing
causing it to form a gummy substance. When that happens, the tape
does not move smoothly through the transport mechanism of the
playback unit. The second issue, in some early forms of tape, was
simply dessication and crumbling of the backing combined with a
shedding of the oxide.
As for the first, the tape can be baked for a period of time at 128
degrees F. (53C) in a clean convection oven to mitigate that problem
provided one is VERY careful during the process. The second issue is
a bit more difficult and requires delicate handling and usually only
one play of the medium to copy and save it.
If you'd like, we'd be happy to take a crack at recovery for you if
you'll send the tape to our lab although we offer no absolute
guarantees.
Bernie Krause
Wild Sanctuary, Inc.
P. O. Box 536
Glen Ellen, CA 95442
707-996-6677 tel
707-996-0280 fax
http://www.wildsanctuary.com
>There has been recent discussion on the Australian mailing list
><birding-aus> concerning the contention that Blackbirds in Australia (whe=
re
>they are not native) don't sing as well as do English Blackbirds. (Turdus
>merula, I assume.)
>
>Years ago, Olivier Messiaen, the French composer (now deceased) sent me a
>two-cassette set of European Birdsong produced by Jean Roche. I turned to
>that to hear at least a French Blackbird. The announcements on the analog=
ue
>cassette were very blurred. Seemed to lack higher frequencies - even with
>my hearing aids to compensate for my age-affected hearing. I could convin=
ce
>myself that I was hearing "Merle noir" because I knew I should be. And I
>think also "Chant du male". But the words were barely distinguishable.
>
>So my query is this: is loss of high frequency sound to be expected with
>long-term storage of analogue magnetic tape? (I have valuable lyrebird
>recordings on Uher reel to reel tape, older than the Roche cassettes.)
>
>
>Syd Curtis in Brisbane
>
>
>
>
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