The motion picture projectionist (Nov 1930-Oct 1931)

March, 1931 Motion Picture Projectionist 45 A Separate Sound Track (Continued from page 18) track. The two heads are tied together by a shaft so that there is no chance of one starting before the other. The Binaural Effect Mr. Phelps: It seems to me that President Crabtree's mention of the binaural effect is worthy of further consideration. I am going to ask if the effect could not be achieved by using two sets of loudspeakers, at opposite sides of the stage, in conjunction with two sound tracks. I think this has dramatic possibilities such as, for example, two characters carrying on a conversation from opposite sides of a wide screen. I should like to hear something on this point. Mr. Irby: In connection with this, several patents have been issued recently calling for binaural recording as well as reproduction and the tests reported were favorable. Mr. Hill : Regarding the recording of two sound tracks on separate film and then reproducing each sound track separately by loudspeakers placed on either side of the stage, this does not work out very satisfactorily because of the fact that each ear picks up the sound from both loudspeakers. The results of several tests, which have been made, show that if a head set is used for reception and one sound track output applied to each head piece, good binaural effect is produced, due to the fact that the sound from one sound track is received by one ear only. If, however, loudspeakers are used, the binaural effect is almost entirely lost. Mr. Palmer: I do not see any particular difficulty with regard to space requirements or the synchronizing requirements arising from using a separate sound track. The apparatus for the projection of sound on the separate track need not be any larger than the present film recorder, which takes up very little space. As far as synchronizing is concerned, there is no difficulty in doing this with the projection machine by the present method used in the studio for keeping the sound recorders in step with the camera. Mr. Edwards: At the Chinese Theater in Hollywood, when the sound recorders were installed the room was packed so that it was almost impossible for the men to walk about. The Microphonic Tubes Most every projectionist has run across a microphonic tube, which could not be used in the photo electric amplifier. A microphonic tube usually produces a howling noise, which increases in volume and rises in pitch, making reproduction impossible. Sometimes the microphonic noise is caused by vibration and sometimes there seems to be no external source of vibration at all. 15,000 Griswold Film Splicers are in constant use daily in theatres throughout the World. The standard film splicer for efficiency, durability and economy. GRISWOLD MACHINE WORKS Port Jefferson, L. I. New York IN WESTERN CANADA! CANADIAN THEATRE SUPPLY CO. Authorized distributors for SIMPLEX— MOTIOGRAPH— POWERS— HOLMES and all theatre equipment of the leading manufacturers. Also, an extensive line of stage equipment Complete Sound Picture Service! 306 Canada Building Winnipeg, Man., Canada Alberta Representative M. L. ADAMSON 9921 — 113th St., Edmonton, Alb., Canada Give This to Your Friend — Have Him Fill It in and Mail to us at Once The Motion Picture Projectionist 45 West 45th Street, New York City Gentlemen : Enclosed please find $2.00 for which enter my subscription for one year (12 issues) starting with issue. (Two years, $3.00.) Name Street .City State Local No.