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Re: [ARSCLIST] Cassette obsolescence - digitizing standards
At 01:26 PM 2/20/2006, Steven Smolian wrote:
These suggestions are all good and fine. However, whoever is not
financed on the scale of a national library, and departs from 44.1
16 bit, expecting to store on a CD must consider the long-term
consequences of a non-standard or only temporarily standard storage
medium with its required investment in harware of dubious future
repairability, processing (changes in the cataloging system) and the
gamble that whatever technological substitute choice is made will be
decodable say, twenty five years hence.
One more item in favour of 44.1/16...
I was going through and setting up my "new" (via the world's largest
garage sale) Dolby 422 B-C-S encoder/decoder. It had the option board
for 19kHz low-pass filters on the input to the encode section (it can
be two channels encode, two channels decode or for channels decode).
With this filter bypassed, the specs for the unit are 20 Hz to 15 kHz
+/- 2dB. The filter degrades the high end even more.
There are several options, including a sharp cut at 20 kHz for Dolby
S, the standard filter, and a special one for TV, which presumably
notches out the 15,734 Hz horizontal sweep frequency.
This is just more evidence that cassettes don't have that much high
end. All cassette machines with Dolby encoding HAD to have the
multiplex filters. A switch was allowed, but not required, as I
understand it. No switch meant that the mltiplex filter (down lots 'o
dBs at 19 kHz) was always in the circuit.
Cheers,
Richard
Tape Restoration Seminar: MAY 9-12, 2006; details at Web site.
Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm