Journal of the Society of Motion Picture Engineers (1930-1949)

6. Ray Hirst, unpublished work on court recording, (Eugene, Oregon) Official Court Reporter, 2nd Judicial District, State of Oregon. Discussion R. H. Ranger (Rangertone, Inc.) : Through the courtesy of the Magnecord Company, I have had the privilege of using one of these equipments and I want to say that it is certainly most intriguing to have the opportunity to do so. The particular reason they were anxious to have me try it was to see if we could record a synchronizing signal on this same tape and I can report to you people who are obviously very interested in synchronizing that it is quite feasible. We have recorded the longitudinal track in the center between the other two tracks, so that you can get synchronous operation using this binaural equipment. I might just add one little reaction that I have had with it and which I confirmed with Dr. Fletcher just yesterday in New York, and that is that not only is it interesting to get two speakers differentiated spatially by this process, but the actual quality of a single speaker, a single person singing, or a single instrument seems to be improved. As Dr. Fletcher said, "I'm too old to figure that out. We'll have to leave that to the younger people." Anon: Is there any provision in your equipment for playback on one channel while recording on the other? Mr. Bixler: No, there is not at the present time. Anon: I have asked that only because there are several applications for which I think that would be a very useful feature. One of them, for instance, is prescored accompaniment in music, while the person ! practices his solo beside it. Mr. Bixler: I might say that there is a single multiple contact selector switch which is used to switch both channels simultaneously from record to playback, and that you could do what you suggest if you were to go into the circuit and build in two switches, in place of this single switch along with seme other minor modifications. C. H. Lankester (United Nations) : In view of the fact, as I understand it, that there is a longitudinal displacement between the record heads, have you found it possible to standardize a positioning of the two heads perfectly accurately, that a binaural recording made on that recorder would play back on another without loss of the binaural effect? Mr. Bixler: I might say that the speed of the tape actually helps in this respect because it's relatively fast and each wavelength covers quite a bit of tape when you "lay" down the signal. On the other hand, heads are supported in fixed castings so that these same patterns are used in all our machines — it's the standard casting we've been using for years, so that insofar as our equipment is concerned, the location of the heads automatically falls in identically the same position in each and every machine. If there is some minor spacing difference the speed of the tape is sufficiently great so as to swamp that difference out. John G. Frayne (Westrex Corp.): I would like to ask Mr. Bixler if he found it impossible to put the two separate heads in the same head structure because the crosstalk between them would then be undesirable. Mr. Bixler: Well, yes and no. I imagine if we had tried to put them right alongside of each other we would have had some crosstalk and I looked with interest at Charlie Davis' disclosure in a recent SMPTE Journal., but it was a matter of expediency in utilizing present equipment and space location on existing castings on which, as I mentioned, we simply replace the existing record and reproduce monitor heads in standard equipment. Thereby it turns out that the heads are spaced from about one-half to about three-quarters of an inch apart automatically. Dr. Frayne: What is the separation now between the two half-tracks — between the two components, rather, approximately? Mr. Bixler: I don't know. John Boyers (Magnecord, Inc.) : 50 thousandths of an inch. Mr. Bixler: Thank you, John. Dr. Frayne: I believe that with about 50 thousandths separation you might work in the decoupler such as Davis discloses. Mr. Bixler: Yes, that is if we had heads that were suitable for that type of mounting. Otto C. Bixler: Binaural Recorder 117