The Bioscope (Jul-Sep 1931)

July 15, 1931 MODERN CINEMA TECHNIQUE THE BIOSCOPE Hi Getting Down to Essentials New' Sound-on-Film Equipment for £245 This extremely ingenious and compact Sound Head has been specially designed to permit largescale standardisation. It has no mechanical or electrical drive, and stress variations are very cleverly taken up by a flexible link between the two lower sprockets. The tiny P. E. Cell is in the projecting cylinder A month or two ago a paragraph appeared in The Bioscope suggesting that there was a field for some inventor and manufacturer who would do for sound what Henry Ford has done for the motor car. The suggestion was that a simplified form of sound head and amplifier should be evolved, cutting out all components that were not absolutely essential to satisfactory reproduction, and then, on mass production methods, turn the outfit on the market at a price in the neighbourhood of £150. The paragraph aroused a good deal of comment, and one of the results of its publication has been to bring a new sound head and equipment to our notice which seems likely to fill the essential requirements of that suggestion. The sound head is illustrated herewith and its extraordinary compactness and beauty of design will need no emphasis. It is, without qualification, one of the most pleasing pieces of sound engineering we have yet examined. Defies Mute Head Eccentricities It can be fitted in a few minutes to any projector and, thanks to its swivel base, in almost any position or angle. It involves no direct drive, mechanical or electrical, and yet it can be fitted to a projector in almost any state of disrepair. The mechanism has been so ingeniously devised that so long as the projector will run, the sound head functions perfectly, regardless of the erratic behaviour, vibration or flicker of the mute head. The operation of the sound head is simple. The film, after leaving the mute head, passes over the large sprocket at the right, thence over the top small idler sprocket, over the curved sound gate, which has no pressure device of any kind, then under the second large sprocket, emerging finally from the underside of the entering large sprocket. Visible Pull Compensation The top small sprocket is an idler, and the large milled nut on its spindle permits of an adjustment of pressure, regulating the braking effect of the idler. All this is fairly straightforward. The interesting feature is the way in which the two large lower sprockets are connected on the far side of the sound head. The method of connection includes a heavy fly wheel. Although these two sprockets are mechanically interdriven, the drive is not rigid and there is a spring link introduced in the drive which gives the connection resiliency ; so much so that, no matter how erratic the pull on the first sprocket, it is smoothed out before the sound head is reached. The film, in passing from one to the other of the two lower sprockets, is looped. An examination of this loop, while the sound head is running, shows how constantly the fluctuations on the pull are being taken up. Neat Optical Assembly So much for the mechanical lay-out. The optical arrangement is equally interesting. The exciter lamps, of which there are two, are contained in the metal cylinders at the left, and there is ample provision for prefocussing and adjusting. In the event of a lamp burning out, the touch of a finger swings over the assembly on which the two lamps are mounted into a new correct optical position instantly. The assembly works on an arc sector and is very simple and precise in operation. The photo-electric cell is of unusually small size and is con tained in the projecting cylinder above the two bottom sprockets. All adjustments and replacements are extremely simple and the head will work at any angle and in any position with equal accuracy. Price May Be Reduced Further This sound head is, of course, the central item in the new equipment. It fulfils every possible need from the sound engineer’s point of view, is as pleasing in operation as it is satisfying to the eye, is small and, finally, is cheap. It is in many ways the most satisfying piece of work in its class that we have yet seen. The other details of the equipment, which is being marketed by the Roth Sound Company, of 159, Queen Victoria Street, are less interesting and naturally less important. In itself the amplification of initial sounds has become a relatively simple and commonplace matter. Amplifier design is fairly well standardised in itself and there are no insurmountable difficulties either with amplifiers or loud speakers. So far as the Roth Sound System is concerned, a straightforward Parmeko amplifier in metal case is standard equipment. This amplifier is small and compact, measuring only about 2 ft. by 1 ft. by 7 in., and the two loud speakers are of conventional pattern. The total outfit is being marketed at about £245, though there is a probability that, if the response is as prompt as is expected, this price may be considerably reduced. The main point is that a serious effort has been made to standardise a British sound equipment designed by a man who has had an unusually wide experience in this field, and marketed at a price that brings it within the reach of the smallest exhibitor. Incidentally, it meets the needs of the growing army of industrial users, and though no publicity has yet been given to this apparatus, quite a number of large industrial users have already heard rumours of it and have been making eager inquiries. The whole move to standardise a simple and efficient talking outfit at a low price is one with which we have the utmost sympathy, and we trust it will be as successful as it deserves to be. NEW DECORATIONS FOR WALLASEY CAPITOL In decorative treatment the Capitol, Wallasey, which has been closed for a short season to enable the contractors to have a free hand, is an excellent example of modem design and colouring. The walls, panels and ceiling have been treated in tones of apricot and peach, the large full length panels being shaded from deep apricot at the base and gradually dissolving into peach. The only breakaway from these restrained colourings is over the proscenium, where the artist has executed a striking bas-relief marine scene, and in the framework of the panels in the vestibule.