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The main point about pre-World War II wire and tape technology would  
seem to be that, while various magnetic formats were already in use  
on radio, they compared poorly to prevailing disc technology. They  
suffered from a gamut of problems ranging from high distortion levels  
and inferior signal-to-noise (AEG Magnetophon), to speed fluctuation,  
sheer physical size of equipment and the chance of the engineer being  
decapitated if the tape broke (Blattnerphone).

Admittedly, the Philips-Miller optical film system offered up to 15  
minutes of high-quality audio, but the film was not reusable, editing  
was nightmarish and the whole process pretty costly. By and large,  
1930s tape equipment did not adequately satisfy the broadcasting  
industry's main criteria of audio quality, duration, portability and  
editability.

In Germany this situation changed irrevocably in 1941 when AEG  
engineers von Braunmühl and Weber stumbled across AC tape bias, where  
the addition of an inaudible high-frequency tone resulted in a  
striking improvement in sound quality — something that was radical  
enough to be discernible in prerecorded German AM broadcasts, if the  
BBC's Caversham Park wartime monitoring reports are to be credited.

In fact, this is not so hard to believe, as the generous bandwidth of  
national AM channels in the 1930s and '40s offered a far higher level  
of AM fidelity than we're used to today. Nazi speeches aside, the  
technical leap forward was most glaringly obvious in prerecorded  
broadcasts by the likes of Fürtwängler and the Berlin Philharmonic,  
as recent CD reissues have adequately confirmed.

While Jack Mullen may have been able to kickstart Ampex by sending  
home a couple of these liberated machines in bits via the no-doubt  
bemused Army Post Office, the final broadcast requirement for tape —  
superior editability — was only really achieved when the notoriously  
fragile German acetate-backed "paper" tape could be abandoned in  
1947-48 in favor of 3M's new, sturdier #111 stock. From that moment  
on tape was definitely superior to disc as a studio medium, even if  
Bing's transcriptions were still pressed up as discs.

Tony B.


>
> Robert Cham wrote:
>>> All the networks started airing one-hour delayed programming for  
>>> the non-Daylight Saving Time stations after the war, and this led  
>>> to ABC (which had been NBC Blue before 1942) allowing Bing Crosby  
>>> to pre-record and edit Philco Radio Time in 1946.
>>
>> After financing Alexander Pontiof's (SP?) development of the first  
>> Ampex tape recorders from the Telefunken recorders brought back  
>> from Germany after WW II.  Crosby used to tell the story of how  
>> the superior signal to noise ratio of tape was responsible for  
>> ABC's decision.  Similar stories of how Telefunken's development  
>> of tape recording during WW II enabled the Germans to confuse the  
>> allied bombing command about the whereabouts of Hitler at any  
>> given time abound.
>>
>> Bob
>>
>>
> This story is almost complete fiction.  First of all, the tape  
> machine was developed and made by AEG not Telefunken.  Two entirely  
> different companies.
>
> Second, that Hitler story is laughable.  Hitler would "be" where  
> ever the broadcast announcer said he was!!!  Besides, Hitler was  
> not making many speeches during the war.  The sound quality of  
> distant radio reception would mask any differences between a speech  
> recorded on tape and a speech recorded on disc.  Steel tape  
> recording on Blatnerphone/Marconi-Stille machines was done by the  
> BBC in England since 1929, so there were other familiar ways to  
> avoid surface noise.  The Philips-Miller mechanical recording- 
> optical playback machine was in common use in Europe before the  
> war, and was capable of long continuous quiet recordings of higher  
> quality than the early tape recorder.  And a freshly recorded  
> lacquer disc was very, very quiet and capable of frequency response  
> way beyond 10 KHz even in the 30s.  There are so many other reasons  
> why that Hitler story is a joke but these should be enough  Those  
> stories only "abound" because they get be repeated without any  
> research.
> Lastly, the entire first season of Philco Radio Time was recorded  
> and edited on DISC.  Tape was only used for mastering and editing  
> starting in the second season, and even then the tapes were dubbed  
> to disc for broadcast.  The tapes were not directly aired until the  
> final weeks of the second season.  Therefore the use of tape had  
> absolutely nothing to do with ABC's decision.  The only part of the  
> story that is true is that Crosby put money into Ampex, but Jack  
> Mullen had already gotten Ampex working on developing improvements  
> on the AEG Magnetophons he had brought back.  But ironically the  
> first tape machines ABC bought were Stancil-Hoffman.
>
> Mike Biel  [log in to unmask]