Path: utzoo!telecom-request Date: Mon, 3 Jun 1991 13:01:31 GMT From: Scott Dorsey Newsgroups: comp.dcom.telecom Subject: Re: Did Western Electric Also Make Sound Recordings? Reply-To: Scott Dorsey Message-ID: Organization: NASA Langley Research Center Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 419, Message 6 of 9 Lines: 50 In article bill@rose3.rosemount.com (William M. Hawkins) writes: X-Telecom-Digest: Volume 11, Issue 416, Message 8 of 8 > I just returned from a visit to the Pavek Wireless Museum in a suburb > of Minneapolis. It's a three year old museum with a major collection > of wireless stuff. It also contains a Vitaphone Lathe, dated 1926, > with a model number of WE D85249 (yes, it looks like a serial number, > but that was on another plate). A single motor drives the turntable > from one end and the lathe screw from the other. The placard says > that Selsyns were used to couple the camera and the recording lathe. > Selsyns are back to back three phase synchronous motors. Well, the > transmitter is a generator and the receiver is a motor. So, that's > how they synchronized sound and picture. Still, I didn't think a > director could make a film a reel at a time, without cutting and > splicing. Something had to be used for sound editing, to go with the > film editing. Yup. The projector actually had mechanical coupling, but the recording was done with a selsyn arrangement. Some of the earlier Vitaphone lathes just had a 60 Hz synchronous motor which would synchronize with the indentical motor on the camera, by virtue of their being on the same power line. Because the loads were different, though, the motor slip was different and they didn't stay synched too well. Sound editing was done with a bank of synchronized turntables, a mixer, and a synchronized cutting lathe. Scenes would be shot with three cameras all synched together, and the film edited seperately, but maintaining the same length and pattern so that the edited film would stay in synch with the sound. Often scenes really would last for a full reel, and the scenes were shot all in one take with no editing within. > The placard also said the lathe cut a 17.5 inch disk, which was used > to press 16 inch copies. The disk on the turntable looked like metal, > and the head looked like it could dig a serious groove in the metal. > The 'card also said 33 RPM. Maybe they dropped the third of an RPM. The disk was a sheet of aluminum with a nitrate or acetate coating on it. There are also some glass transcription discs out there with similar coatings, though I don't believe they were used for Vitaphone. Makes me glad I live in the 1990's, with my nifty Nagra. Or is this the 1960's? Something like that. scott