Re: arsclist Transfer of multiple copies, was: Full 3-D mapping of groove?

["George Brock-Nannestad" <pattac@xxxxxxxx>]

From: Patent Tactics, George Brock-Nannestad

in the latest of a really long and quick list of exchanges Mike 
Csontos wrote:

> 
> It is unlikely that a pop or click would occur at the same point on
> three or more copies.  By completely rejecting data that deviates by a
> significant amount from the average, the defect would be removed and
> the "good" data from the other copies used.
> 
> This same technique might also remove distortion products due to
> record wear to a greater extent than simple averaging.
> -------------------
> With processors operating at two billion operations per second soon to
> reach the consumer market, the capability for this kind of analysis
> should be available.

----- now, that is precisely what the Packburn (and the MouseTrap 
from England) does in its switching mode for just one record and 
using each groove flank as an independent source, only in 
analogue. I am continuously surprised that no-one has offered a 
computer program package that will do the same digitally. There 
are serious problems, though: there is a need for an "azimuth 
corrector" function, because sadly, we cannot trust the right and 
left channel to be sampled at the same place in the waveform by 
ordinary pickup mountings and swiveling tonearms. And the best 
pickup for a pressed mono 78 is the Ortofon C (recently revived 
since its inception in the late 1940s) - it is a mono pickup. Stereo 
pickups do not have an impressive channel separation (except for 
the ELP LT, of course) - but the Packburn still does a good job.

> 
> The significance of this now is that archivists might well want to
> consider preserving three or more copies of significant early
> recordings to have them available for future processing.

----- The Danish National Collection at the State and University 
Library keeps 5 copies when possible. However, when persuaded 
to have the singer Vilhelm Herold re-issued on NIMBUS Prima 
Voce, they still sent their pristine best copies for reproduction on 
arguably the best acoustic reproduction machine ever made, which 
unfortunately leaves the records un-pristine. So not even archives 
can be trusted to treat their treasures non-invasively.

Kind regards,

George

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