Hi Tom:

Been out of touch for a few days here....just noticed the post.

I think you've managed to find most of your answers in the Kellogg 
articles. Based on the dates on some of the documents I have on file, it 
would appear that Westrex issued modification kits for their RA-1231 
recorder and RA-1251 series dubbers in June 1949. RCA introduced a few 
different mag kits for use with their PR-23 recorders and dubbers in 
1948, but for some reason I never really saw too many of these in use.

Paramount had adopted 17.5mm mag recording for production work by April 
of 1950, but were still transferring to optical tracks for cutting and 
re-recording. The transports remained similar to their optical 
predecessors, and were interlocked to the cameras by 3-phase selsyn systems.

I think the first dedicated RCA PR-41 series portable magnetic recorders 
(many of which were 17.5mm) were introduced around 1952, but I don't 
have the manuals handy to verify the printing dates at the moment.

Western Electric (Westrex) introduced their RA-1467 series 3 track 
magnetic recorders and portable mixers in early 1951, which saw service 
on various stereo films such as "The Robe" shot during the 1950's.

As stated by various sources, by 1952, Hollywood was about 75% magnetic, 
even though the many of the editors hated it, because they could no 
longer "read" the track modulations. With the advent of the DAW, they 
now have their wish!

--Scott

Scott D. Smith CAS
Chicago Audio Works, Inc.

On 2/9/2012 7:15 AM, Tom Fine wrote:
> Hello ARSC brain trust:
>
> Does someone know exactly when folks in Hollywood started using 
> magnetic-coated film in their sound recordings? I found this article 
> from a Dolby executive:
> http://www.cinematechnologymagazine.com/pdf/dion%20sound.pdf
> which seems to put the date around 1952, with the development of 
> Cinerama, which apparently used stripe-coated magnetic tracks. I think 
> Westrex developed its stripe-coat and full-coat recorders around that 
> same time, and that magnetic recording of master tracks started to 
> become common as the various widescreen formats developed in the early 
> 1950's. Is this historically correct?
>
> Thanks in advance for your input.
>
> -- Tom Fine