Re: [ARSCLIST] Soviet audio tech standards

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

Dear All,
    I hope I may be permitted to offer a "lateral" solution to Will's
problem. When I was a disc-cutting engineer, I was receiving a large
number of customers' tapes without any indication whether they had been
recorded on a Japanese machine (NAB equalisation) or a European machine
(CCIR). The only solution was to commission a dedicated tape-playing
machine. It had four identical audio channels, two for the actual audio
(which might be stereo), and two for the advance-signal for the
disc-cutter's "advance signals" (so it could modify its groove pitch and
groove depth) according to the signal about to be cut. But I am becoming
diverted.
    The equalisation problem was solved by each tape amplifier having
nine-way switches for the nine equalisations then standard, calibrated
in microseconds. Then I would move this switch around until the audio
sounded at its best to my ears (judged on professional loudspeakers with
which I was familiar).
    Will's problem might be circumvented by the accompanying
documentation carrying the timeconstants used for the reproduction.
Thus, at any further time a user might be able to change things by
making a reasonable choice. That is, he could use a "step filter", in
which one of the timeconstants was the one listed in the documentation.
Peter Copeland
Former Conservation Manager,
British Library Sound Archive. 

-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:ARSCLIST@xxxxxxx] On Behalf Of Prentice, Will
Sent: 20 March 2006 15:40
To: ARSCLIST@xxxxxxxxxxxx
Subject: [ARSCLIST] Soviet audio tech standards

Colleagues

An acquaintance is undertaking a digitisation project in various parts
of the former Soviet Union, involving digitising many hundreds of hours
of 1/4 inch analogue tape, recorded between 1953 and 1991. Recording
speeds are generally low (1 7/8 & 3 3/4 ips), all are mono, mostly full
track.

What equalisation standards are likely to have been used? My vague
understanding is that much (most? all?) Soviet audio technology came
about through reverse-engineering western products, and thus any
standards would accordingly be western derivatives. Is that overly
simplistic? Would that mean European standards or US? If it's of any
use, the recording/playback equipment which survives carries either a
"Romantika" or "Tembr M3" brand name. 

The archivists there could shed no light on the question, and in my own
experience in former Soviet Republics, basic AV technical expertise is
often very thin on the ground today.

In view of the difficulty in obtaining and maintaining quality machines
with such slow playback speeds, they're thinking of ingesting at
double-speed. This obviously throws up questions of appropriate EQ
curves, hence my question.

(A long shot I realise, and while I half expect tumbleweed in response
to this message, I also know not to underestimate the collected
experience of the list ;))

Regards

Will

Will Prentice
Technical Services
British Library Sound Archive    Tel: +44 (0)20-7412-7443
96 Euston Road                   Fax: +44 (0)20-7412-7416
London  NW1 2DB                  http://www.bl.uk  
UK                               http://cadensa.bl.uk (online catalogue)

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