RE: arsclist Re: Elgar and Menuhin

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

Dear All,

    Oh dear, this is going to be a long answer. I shall re-key the evidence
as described in my Manual of Analogue Sound Restoration Techniques section
5.34 (the Blumlein system is described earlier):

5.34. The Gramophone Company System

    A Gramophone Company report dated 12th June 1930 describes how HMV
engineers hoped to evade Western Electric patents. Their Dr. Dutton made a
trivial modification to a Western Electric microphone capsule (cutting
"slots" instead of "grooves" in the backplate) to evade one patent; and a
very conventional valve amplifier was built to replace the Western Electric
push-pull design. A cutterhead invented by Angier, Gauss and Pratt (British
Patent 372870) uses ideas voiced in that report.
    When trials began in Abbey Road Studio 3 on 16th December 1931, the
matrix numbers were followed by a "swastika", actually the mirror-image of
the swastika later used by the German Nazi party. When E.M.I was asked for
an explanation of this in 1964, the enquirer was told that it meant
"recorded by the Gramophone Company system", which seems quite ambiguous;
but I must also report an alternative explanation (Ref. 26). This says the
mark identified a moving-coil cutter (presumably Blumlein's), and that the
swastika changed after complaints from various continental export markets.
    I have not been able to distinguish between these two explanations, and
it is even possible that *both* are true. If the first is correct, then only
the cutterhead was novel. It was in fact a classical moving-iron cutter, and
one of the features (in Claims 1 to 4 of the patent) was that the recording
characteristic was defined by the electrical features of the coil, as we saw
in Section 5.12. Fortunately E.M.I did not pursue these claims, or a great
deal of sound-recording would have been strangled at birth! However,
previous systems (like Western Electric) had used the same principle but not
claimed it in a patent.
    The resonant frequency of the armature was given as 5400Hz in the
patent, with a peak of +4dB or +6dB depending which graph you look at.
Spectral analyses of surviving discs suggest a lower frequency and a lower
peak than that, although the patent shows five designs of armature (which
could have had different resonant frequencies), and the effect of the
cutting stylus was not quantified.
    The constant-amplitude turnover was quantified with the words "for
example, 250 cycles per second."
    The performance of the microphone and amplifier do not seem to be
documented, and we only have the historic photograph of Elgar and Menuhin at
their recording of Elgar's Violin Concerto in July 1932. This shows a
Blumlein HB1 microphone, although the recordings all have "swastikas." It is
not generally possible to hear any difference between "swastika" recordings
and others (possibly because they used the same microphones). Current
practice is therefore to treat the former as if they were recorded to the
"Blumlein 250Hz" curve. 
Ref. 26: Bernard Wratten, in a letter to Jerrold Northrop Moore dated
24-01-74, quoted in the latter's book "Elgar on Record" (Oxford University
Press, 1974) in the third footnote to page 174 of the paperback edition. 

    Personally I disbelieve Reference 26 on the following grounds. As far as
I can tell, the Menuhin/Elgar recording was the *last* to carry "swastika"s,
and it was made in July 1932. But the right-wing government in Germany did
not take office until October 1933 (I think), so it cannot have been a
causal relationship. I am happy to be corrected about this, and look forward
to nailing down the ambiguity if anyone else can help.

Peter Copeland
<peter.copeland@xxxxx>
 
-----Original Message-----
From: Russell W. Miller [mailto:rwm@xxxxxxxxxxxxxxx]
Sent: 30 August 2001 13:59
To: ARSCLIST@xxxxxxxxxxxxxxxx
Subject: RE: arsclist Re: Elgar and Menuhin


Peter Copeland writes:

> It's a Blumlein HB1 moving-coil microphone (the one which had the
> electromagnetically generated field, rather than the permanent-magnet
> introduced about 1934). However, the *recordings* made at that session
> probably weren't done with Blumlein amplification or cutterheads; the
> mirror-image swastika in the shellac indicates the Gramophone Company's
> moving-iron system.

Peter, I may have my history a bit confused then.  I understood that the
system represented by the swastika, and subsequently by the square, was the
system Blumlein had developed for Columbia.  This was the system denoted by
a "C" on Columbia discs, and the Gramophone Company was able to use this
technology when they joined with Columbia to form EMI.  If I have this
wrong, please set the record straight!

Thanks,
Russell W. Miller

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