Movie Makers (Jun-Dec 1928)

paniment, but was preceded with an opening address by Will H. Hays and some orchestral and operatic numbers by Anna Case, Marion Talley. Martinelli, a jazz orchestra and a couple of vaudeville specialties. This device was based on an idea developed by sound engineers seeking to increase the tonal volume of long distance telephone messages. The idea was of no use for telephone transmission so it was passed on to other members of the experimental staffs of the Bell Experimental Laboratories and the Western Electric Company. The device was largely based on the use of electric regeneration, much the same as you will find in your radio set, and used in what is known as the "public address system", which amplifies speeches at public meetings. Adapted to the motion picture, the device took the sound off phonograph records, converted sound into electrical impulse, steeped it up by means of tubes and projected it as sound in any desired volume. Synchronism between the sound source and the sound itself was attained by operating the camera or projector machine and the phonograph from opposite arms of the same motor. Since the phonograph marked so that precisely the proper frame is in position at the aperature. The discs are specially made with 400 lines to the inch. They run ten minutes, or the same time as the single theatre reel. If the film is broken and spliced, there is a slight loss in synchronism, but every ten minutes a new reel starts, so that these slight gaps are not cumulative. The disc can be run up to about 18 times, so that two or more discs are supplied The Recording and Projection of Vitaphone Sound Film. and the projector shared the common source of motion they were bound to keep in step. Recording can be done at the point of origin of the sound, it can be made at a distant point, by wired transmission, or it can be added, if desired, at a later time. In such a case, the picture is run off, the sound is timed to fit, and recorded on the disc operated, as before, by the other side of the motor arm. Thereafter sound and sight are bound to be in harmony. The discs are cut to permit the needle to slide into precisely the proper point on the groove. The film is Center: Taking the Picture in a Sound Proof Booth; Left: Recording the Sound on a Wax Disk; Above: the Synchronised Projection of Film in the Pre Jector and of Sound from the Disk in a Theatre Projection Booth for each week's engagement. They will respond longer, but the tone is not clear. The film is more lasting, since it is nothing more than the regulation film such as is used for silent pictures. The pictures are run at a uniform speed of 24 frames per second. To run slower or faster will affect the tone, just as running a Victrola above or below 78 turns per minute will affect the pitch. But while the Warners were perfecting the Vitaphone, T. W. Case had succeeded in interesting William Fox in a device for the photographic recording of sound, and Warner Bro thers, who at that time held the exclusive right to use the "public address system," licensed the Eox-Case Company to employ the device for its Movietone. A press demonstration of Movietone was held in October of 1926, but it was not until March that the first public exhibition was given in offering the musical accompani ment to "Seventh Heaven." But at the October showing Fox-Case offered a number of short lengths with talk including a series by Racquel Meller and a bit by Chic Sale. Movietone is what is known as a "sound track" machine, as distinct from the "disc" form, represented by Vitaphone. The sound is imprinted on a band to one side of the frame eight hundredths of an inch wide. For this reason the Movietone screen does not show a picture as wide as Vitaphone, since the sound must be masked off. The sound track is merely a succession of bands of varying density, which gives another classification. Movietone is of the "band" type, instead of the "fixed density," which will be explained in a moment. The sound is photographed on the film by means of a light beam. This light comes from a special form of light tube, known as the AEO light, the letters standing for "alkaline earth oxide." In recording, one or more microphones are placed close to the action stage to receive the sounds. The vibrations of the sensitive disc of the microphone are conveyed into an amplifier. The higher the tone, the greater number of vibrations. The higher the vibration, the greater the intensity of the light. And this light, shining through an almost microscopic slot, imprints the film with greater or less force. The brighter the (Continued on page 603) 575