The Technique of the "Movie-Tone"

Radio Record, Volume II, Issue 47, 7 June 1929, Page 3

The Technique of the "Movie-Tone"

Possibilities of Great Future Development

NLY a few weeks back the advent of the "movie-tone’ in New Zealand was heralded, but it was impossible at the time to outline its technical features. Its success has been unique, and it is quite safe to predict that is is essentially the entertainment of the future. Already, several theatres in New Zealand have installed ‘or ate installing ‘this new apparatus, and it seenis that before. very long all large picture theatres will be thus ‘equipped. The technique of the system has been almost perfectly developed the ough radio, A few years ago, it wy have been ridiculous to have sugge’ ‘sted that one could. see and ‘hear what .was enacted, say, six or twelve meyths ago at a scene thousands of miles away, but now this is an accomp) shed fact. The greater number of. movie-tone fili:is released here, with the exception of news items, have.the actions accompanied by musie rather than. speech. .The result of, this is that a special score can be written. for the film, and at-the critical points, the music can be suspended and the voices of the ac‘ors reproduced. ’udibility is perfect when the actors speak perfectly clear, and the language of: these contrary. to accepted ideas. is of.4 very high standard. The orchestral musie is certainly perfect, and the fict that one of the largest theatres _ iy New Zealand has covered the orches-

tral pit with a decorated lattice is significant of future development. Systems of Talking Film. , O far, the moyie-tone’ system has been most widely used, but there are two others that will be introduced ere long. The vitaphone and the phototone. The former is a discrecording system while the latter re sembles the movietone in. that the sounds are produced through medium of light impressions on the side of the film. On examining a piece of movie-tone film, series of bands varying in their density can be seen. These resemble film negatives, though not so intricate ns far as impression. When the film passes through the projector it is taken to a point lower down, where a strong light is thrown on to the bands at the side. The variations in the intensity of these causes a variation in the intensity’ of the light, passing through. This is. recorded by a photo-electric cell. This latter, known usually as the "eye" of television, is a valve which may be -likened to microphone. It transforms variations in light into variations of electric current, whereas the micro‘phone transfers variations in the ether

into variations of electric current. From this point on, amplification is the same. ° The. weak currents’ from the photoelectric cells are taken to an adjacent amplifier, comprising two A.C. amplifying valves of the usual receiver type. The strengthened signals are passed on to a power amplifier, where they are handled by five more valves, the last two being transmitting valves in .pushpull. From this point relay lines carry the signals to the points at which the speakers are located. In the case of the Paramount Theatre, Wellington, the management of which enabled us to get the full technical particulars, eight dynamic cone speakers are situated in two columns at the sides of the screen. From these the signals are thrown perfectly t- the rear of the theatre. In making a movie-tone film, the process is just the opposite. ‘Speech vibrations are carried to a neon lamp, which causes fluctuations in the intensity of . ght, resulting in bands of different densities corresponding to the differences in the strength of the impressed signal. As it is almost impossible, both from the secording and reproducing standpoint, to have the photo-electric

apparatus and the apparatus concerned with the photography exactly beside one another, the tone process is retarded eleven exposures behind the photograph. The photophone, working on the same principle, varies only in that the bands vary in size and not in intensity. It, is considered that from a point of view of durability, they are more suitable than the movie-tone. Both can be used in the same apparatus without adjustment.