RE: arsclist cylinder frequency range

["Copeland, Peter" <Peter.Copeland@xxxxx>]

Dear All,
    From about 1927 Edison's Blue Amberols were electrically recorded, and
although this was achieved by mechanical dubbing from electrically-recorded
Diamond Disc masters, I would expect this type of cylinder to have the
most-extended frequency-range in the treble. The trouble in measuring this
is (a) there is always a gradual changeover from "music" to "noise" as you
go up the frequency range, so it's a subjective judgement even with a proper
frequency analyser; and (b) your web-delivery plan muddies the water
further, because noise consumes more bits than anything else when digital
compression schemes based on psychoacoustics are involved.
    We are facing exactly the same problems here at the British Library, and
I'm afraid my response at the present time must be :
(1) Learn the properties and sampling-frequency options of the system you
propose to use for web distribution;
(2) Wire up the facility to compare the original analogue sound with the
compressed version on a changeover switch, listening upon wide-range
equipment in quiet conditions;
(3) Use several high-frequency rolloff solutions, try them all, and pick the
one which does least damage to the recorded performance when comparing
"before" with "after".
    I would also add that some hardware for web applications also does
automatic volume controlling. You will need to eliminate this (or
reverse-engineer it), to prevent yet more noise corrupting the music.
    Even so, when you have done all this, I suspect LoC's choice of 11kHz
would not be significantly wrong!
Peter Copeland

-----Original Message-----
From: David Seubert [mailto:seubert@xxxxxxxxxxxxxxxx]
Sent: 16 January 2002 17:57
To: ARSClist
Subject: arsclist cylinder frequency range


Hello,

Can anybody tell me what the maximum frequency range present in a well 
recorded wax cylinder might be? We are trying to determine what the minimum 
sampling rate should be when converting a cylinder recording to a 
compressed file format for web delivery. Since the sampling rate only needs 
to be twice the maximum frequency, we'd like to use the lowest one 
possible. I see that the Library of Congress used a sampling rage of 11Khz 
for some 78s in American Memory, but that seems too low to me.

Thanks,
David
David Seubert, Curator
Performing Arts Collection
Davidson Library Special Collections
University of California
Santa Barbara, CA  93106
(805) 893-5444 Fax (805) 893-5749
mailto:seubert@xxxxxxxxxxxxxxxx
http://www.library.ucsb.edu/speccoll/pa/



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