I was sent this by Andrew Emmerson who edits a journal called
"405 Alive" for enthusiasts of television history. He received the
question in a letter from a reader. Please reply to the digest and
to Andy directly.
> From (Andrew Emmerson) midshires@cix.co.uk.geentroep [ drop .geentroep to reply ]
>
> "In the centre of George Cushing's collection of organs at Thursford,
> Norfolk, is a superlatively restored Wurlitzer organ from, I think,
> the Plaza Leeds. Upon it Robert Wolfe gives dazzling performances
> throughout the summer. In one of them, a tribute to the Movies, he
> played Lullaby of Broadway and Jolson's Mammy, accompanying the film
> clips projected on a huge video screen.
>
> What puzzles me is that he was in tune with the film sound. Films are
> shot at 24 frames a second, but television scans at 25 frames (fields)
> a second. This accounts for the Titanic film being several minutes
> shorter on video than in the cinema and makes the sound, both music
> and speech, about a semitone higher (sharp). So how did Thursford do
> it?
>
> My Owl's Book of Knowledge tells me that musical 'A' is 440Hz, and
> 'A sharp' 466.16Hz; thus note 'A' on film projected to video will
> be 25/24 x 440 = 458.33Hz, producing an audible dissonance even if
> transcribed up a semitone. Even Bernard couldn't tell me!"
Jeffrey Borinsky
[ There are 3 TV transmissions standards that I remember: NTSC,
[ PAL, and SECAM. NTSC, used in the US, transmits at 30 frames
[ (60 fields) per second. 24 frame per second movies are transmitted
[ synchronously by scanning some frames more times than others.
[ Thus there is no speed alteration. The speed problem represented
[ by 25 frames per second (PAL, right?) is interesting. Since
[ music harmony is "relative", I would expect that only those
[ with "perfect pitch" hearing and those trying to "play along"
[ with the tape at the piano would be bothered by the playback
[ speed (and pitch) difference you describe. -- Jody
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