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ARSCLIST  November 2009

ARSCLIST November 2009

Subject:

Re: power line frequency

From:

Michael Biel <[log in to unmask]>

Reply-To:

Association for Recorded Sound Discussion List <[log in to unmask]>

Date:

Tue, 3 Nov 2009 17:53:06 -0700

Content-Type:

text/plain

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text/plain (193 lines)

The change in electrical power in Germany would not affect the
recordings of Hitler's speeches made here in the U.S. and in other
countries.  I have some complete speeches I recorded directly off the
discs recorded by CBS in Philadelphia and NBC in Chicago, and excerpts
from many other albums.  What about all those classical recordings
recorded on disc and tape in Germany during those years?  They also
would be off-speed if Hitler is off-speed.  It is quite true that many
78s were really recorded at 75 and 76, but this dates back into the
acoustical era when almost all recording machines were spring or falling
weight driven.  Many companies continued to use the falling weight
turntables into the 30s.  But there is one more factor.  ALL of these
mechanical machines had their speed controlled by centrifugal governors,
and many electrical motors also were likewise controlled.  The motors
were set to run fast and would then be reduced by the governor.  If
governor control was used, mains voltage and frequency would have no
effect, even if it varied during the recording.    


Mike Biel  [log in to unmask]  


  -------- Original Message --------
 Subject: [ARSCLIST] power line frequency
 From: George Brock-Nannestad <[log in to unmask]>
 Date: Tue, November 03, 2009 7:09 pm
 To: [log in to unmask]
 
 From: Patent Tactics, George Brock-Nannestad
 
 Hello,
 
 from time to time this crops up on ARSCLIST (although I can only locate
April 
 2004 at the moment), because it is highly relevant, both for recording
and 
 reproduction done with synchronous motor drive and when using
stroboscopes. 
 We are now so fortunate that we have a reasonable certainty of having
either 
 50Hz or 60Hz (not to mention 400 Hz in aircraft), but that was very far
from 
 the real world, say from the 1920s and until ca. 1965. I have a fairly
good 
 impression of what went on in the US and in the UK (and in central 
 Copenhagen, Denmark, they had DC until 1962!).
 
 Ca. 1980 a Danish record collector who had started late in academia,
studying 
 the subject of contemporary history, decided to write his thesis for
B.Sc. on 
 historians' problems in using sound recordings as historical sources.
His 
 name was E. B. Mortensen, in the 1970s a frequent contributor to
Talking 
 Machine Review, and his thesis was huge. It was a rambling discussion
based 
 on a lot of misunderstood acoustics, but it impressed immensely his
non-
 technical history-based supervisors. He took innumerable measurements
and 
 made innumerable calculations that were quite misleading, and he used
his 
 ears. He purported that most of the 78s we listen to were really
recorded at 
 75 rpm. He discovered that Hitler sounded much better if the speed of
his 
 recordings were reduced by 10%; the speech became much less hysterical
and 
 probably more threatening, cajoling, etc. Without any source he claimed
that 
 the Germans had reduced their power line frequency from 1935-1944 to
47.3 Hz 
 to save power, and that consequently, when we reproduce at 78 rpm we
get an 
 erroneous result. 
 
 I was given a copy of the thesis by someone who wanted an independent
review. 
 I thought the conclusions on Germany were utter nonsense, but how do
you 
 disprove such a statement? I worked my way through volumes of the
foremost 
 German electrotechnical journal, Elektrotechnische Zeitschrift, the 
 publication of which petered out in 1944, due to shortages and the fact
that 
 the pages were quickly filling up with obituaries and death notices.
Nowhere 
 did I find anything that could prove or disprove his statement, and
anyway, 
 all synchronous clocks would run slow. It was counter-intutitive to a 
 technician, because if heavy machinery needed more power at a lower
speed it 
 would simply draw a higher current, and the real saving only occurred
during 
 the actual run-down from 50 Hz to 40-something Hz, which could be
termed a 
 one-time flywheel effect. I did find papers on the instability of
frequency 
 and slow regulation of hydroelectric plants, but I also found the
frequency-
 stabilised converters used for film cameras. Apparently no problems in
the 
 professional sector. As Allan Koenigsberg said a short while ago, "How
does 
 one prove a negative?"
 
 Now, 26 years later I am finding material that seems to indicate that
there 
 may have been some truth to Mr. Mortensen's assumption: at least during
1944 
 they did lower the mains frequency to 45 Hz, and indeed it appears that

 Germany towards the end of the war had been split into two sectors, one
using 
 43 Hz and the other 41 Hz. There is a strange logic to why this would
save 
 energy. You may skip the next if it is too detailed.
 
 The frequency really only influenced operation of motors: all AC motors
would 
 run more slowly. This meant that e.g. rolling mills, overhead cranes, 
 elevators, etc. would have a lower throughput and thereby a lower power

 consumption. The voltage was maintained, so lights, heating, vacuum
cleaners, 
 etc. would not be influenced. The only real problems would be in the
iron 
 used as cores: it would be more likely to saturate and hence the
efficiency 
 would fall and transformers would risk overheating. The heavy
electrical 
 industry had already optimised the balance of copper and soft iron, and
that 
 was for the specified frequency. By the way, house wiring was made with
iron 
 wire and small transformers used zinc wire in the last days of the
Reich.
 
 Now, there are still a lot of open questions here: was any recording
and 
 reproduction done at all at mains synchronous speed at that time? And
what 
 was the timeframe: Hitler's speeches had been recorded from about 1932,
and 
 surely they could not suffer from this phenomenon before the terrible 
 shortages set in. But I am certainly no longer cocksure. But, as I have
said 
 on this list before, one of the German broadcasting houses had a
quartz-
 controlled power line installed for their tape recorders and
gramophones in 
 the 1950s. Perhaps not to re-live life's complications.
 
 I have also recently found via the website:
 
 http://vwgc.org.au/VWGCGramNotes.htm
 
 that Western Australia had 40 Hz until 1958, and they show a 40 Hz
78rpm 
 stroboscope.
 
 The BBC was aware that there might be variations in the mains
frequency, and 
 on: 
 
 http://www.btinternet.com/~roger.beckwith/bh/grams/grams_4.htm
 
 you may find calibration discs and a stroboscope "For use when mains 
 frequency at the time of recording differs from that at reproduction".
In 
 reality it was no more than 2 Hz either way, and the circles were
marked in 
 difference frequency, rather than rpm. The central German broadcast
archives 
 had actually informed Mr. Mortensen that the recordings of the German
radio 
 stations were marked on the label with the mains frequency! But he
obviously 
 did not believe them.
 
 The story continues. I would not be surprised to learn that northern
Italian 
 records were cut with machines run off 14 Hz or 16 2/3 Hz, which were
in use 
 for traction purposes. Let us see if a type-wri-toon will work here:
;-) - 
 yes, it did.
 
 Kind regards,
 
 
 George

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