Reinventing the pallophotophone
Hello Everyone,
I’ve known Russ DeMuth for a few years now and I have learned much from working on different projects with him.
For the last couple years he’s been telling me about the work he’s been doing with the Schenectady Museum and some of the technical challenges he had to invent around. I never quite understood the magnitude of what he was working on, until I heard the recording of Edison’s voice.
Recently, Russ also took some time out of his busy day to give me a tour or of the museum and the people he’s been working with. It gave me a first hand opportunity to see the massive historical archives the museum has of GE pictures, film, audio and products.
Furthermore, during my tour I was sworn to secrecy before I was allowed to see the latest that the museum is working. It seems that the some of the best findings are yet to come.
After the tour I asked Russ a few questions to better understand how he got involved and how he cracked the PalloPhotoPhone. Here is what he had to say.
How did you get involved with the museum?
I started working at the Research Center in 1995 with John Schneiter on a number of projects related to electro-optical systems used in the inspection of aircraft and quartz products. John became a founder of GlobalSpec and we kept in contact over the years. In 2008 he became a member of the Schenectady Museum Board of Directors and met Chris Hunter, Curator of Collections and Exhibitions. Recently, Chris discovered 13 reels hidden in boxes with the large collection of movie film in the Museum basement. The reels were labeled “radio programs of 1929-1930” andthey appeared quite different from early movie films. From his background in optics, John had an idea about the nature of the recordings and contacted me in August 2008 to discuss building a machine to playback the sound tracks. The Museum had components of a 1930 vintage PalloPhotoPhone, invented by Charles Hoxie, which we examined to determine how the device operated.
What got you interested to work on the Book Film Recorder (PalloPhotoPhone), and how did you start deciphering it?
Beginning in August 2008, we had a number of lunch hour meetings at a local restaurant to discuss the early design of the hardware. Little information was documented on the optical components, operation, and film speed used by Hoxie.Due to the age of the 13 reels of nitrate film and poor condition of the film there was concern about feeding the film thru a transport mechanism. Film restoration companies would not copy the film because they lacked sprocket holes. We discussed the basic principles of the invention and believe we could design a system to playback the sound. There was a risk that some unknown modulation technique would make sound playback impossible to decipher. To the left is a broken piece of film that was found in boxes.
The early hardware used a recent movie film “City Slickers” to test the optical system and sound output capabilities. Current movie film uses sound tracks adjacent to the movie frames. Based on using this film to debug the hardware made it more likely the system would work with the 1929 tracks.
What where some of the challenges in getting it to work, did anyone believe you could do it?
Building the hardware to playback the multi-track film required a long optical 0.001 inch wide slit and a means to move the phototransistor detector across the tracks. The initial hardware would play only a single track due to narrow slit that was readily available. With the help of a researcher at the center we fabricated a 25 mm length slit which allowed scanning of all the tracks. The basic optical arrangement is shown in this figure:
The lack of drive sprockets required a friction capstan drive with adds to the difficulty of speed control. Speed control is critical to the music sound quality. Work is continuing to improve the design.
Do you have any material of the original invention (pictures, patents) or on the person who invented it?
There are a number of historical documents that can be found on the web discussing Charles Hoxie’s PalloPhotoPhone and descriptions of the optical system based on his invention. Chris Hunter, also collected a number of documents and photos from the Museum Archives. The photographs and patents showed different designs of the early hardware and were key to understanding the optical design
In June 2010, Chris discovered in the lighting category of the photo collection (and not with radio, television, or telegraphy) were pictures of the GE sound recorder. They alternately called it the film phonograph or the book film recorder. The patent for this device was found:
There are two images from the Research Lab in 1929 where the third reel is vertical on the side of the machine. Also attached is an image of Clarence Hewlett, the inventor of the continuous sound recorder.
An April 1929 article in The DiGEst stated “A new machine may read to us the masterpieces of Literature” and tells the story of the multi-track system.
This announced the recording hardware shown on this photo:
The work of another researcher CJ Collins was also discovered relating to sound on film technology:
What else does the museum have that the general public isn’t aware of? Do they have volunteer opportunities if people are interested?
The Schenectady Museum Archives is an internationally significant collection filled with millions of advertising, business records, 2000 books, 900 films, 10000 patents and 1.6 million photographs relating to the history of the electrical industry and General Electric. The collection is an invaluable resource for the study of the electrification, industrialization and urbanization of American society and attracts researchers from around the world. The Archives, together with the 40000 objects in the collection, document the impact of the electrical industry.
The other giant collections are the motion picture films and video, totaling over 1800 items, and the Advertising & Sales Promotion Collection, which is contained in 1200 boxes.
The Museum has a number of volunteer activities and is soliciting grants to create a unique radio and television, motion picture history display based on the collection.