Kinematograph year book (1944)

Film Exhibition and Kinema Technique. 217 G.B.-Kalee, Ltd. — The current "T" series of the British Acoustic range is offered with three different types of soundheads — the G.2 and P.T.I, and P.T.2 — and with " Duosonic " speakers, in three sizes, all with Lansing Shearer dynamic units. This equipment has been fitted to the Kalee 12 projector as a complete unit. There are seven versions of this equipment for theatres from 800 to 1,800 seats. The amplifying chain in all the "T" series is the new S.20 type, which in conception and design is a radical departure. The place of the plurality of units which previously linked the photo-cells in the soundheads to the speakers is taken, in the S.20 design, by two units only. The fiist, of small overall dimensions for accommodation on the operating box wall between the projectors, comprises in extremely accessible form, and as one electrical unit, two head amplifiers, main fader, changeover switch, and pre-stage amplifier. The second, of rack construction occupying the minimum floor space, comprises power amplifier, switch control panel and exciter lamp current supply units. The rack is designed to give absolute and immediate accessibility from the front of every component mounted on it. The push-pull negative feed back output stage of the power amplifier gives 16 speech watts with no measurable second harmonic distortion and not more than 2 per cent, of third or higher harmonic content. Every valve in the two units is metered, and a separate output valve provides five speech watts for the monitor speaker. Due to the use of cathode coupled cells and the elimination of iron-cored chokes and transformers from all but the power output stage, hum level and liability to outside electrical interference is nil. RCA Photophone, Ltd. — RCA Photophone has continued actively during the fourth year of the war, installing numerous Air Force and Army camp kinemas with High Fidelity sound reproducers, as well as manufacturing other special apparatus for Government use. A fair number of civilian kinemas have also been equipped where the Board of Trade has granted the necessary permits. In addition to preview theatre installations already made for the Ministry of Information and the War Office, the company has now completed a similar installation for the Air Ministry. A further busy programme of a similar nature to that mentioned above lies ahead for the coming year, a consigment of the very latest design of High Fidelity sound reproducer equipments having recently arrived in this country. The Radio Corporation of America, parent company of RCA Photophone, Ltd., continues to work day and night on the production of highly scientific apparatus in addition to the manufacture of their standard equipment now nearly all devoted to the furthering of the war effort. The new RCA Research Laboratories at Princeton, New Jersey, are constantly evolving new processes and equipment, amongst which some of the more notable items this year have been the introduction of the so-called " radio nail gun " and the " radio sewing machine," devices utilising radio frequencies of about 200 megacycles for the instantaneous bonding of various materials. Western Electric Co., Ltd. — While full provisions continue for the servicing and maintenance of all Western Electric installations in use, production of sound film apparatus is suspended for the period of the war, with the exception of certain equipment for Government requirements. The technica and production energies of the company are mainly concentrated on experimental work, design, and manufacture of specialised apparatus of a nature for which past experience and research in the various channels of the sound transmission field have made the organisation peculiarly fitted. During the war years the rate of technical advance is accelerated far beyond the speed of progress in normal times, and the benefits of this intensive development wil be reflected in the new sound equipment for both recording and reproducing purposes. The post-war Western Electric system will be of entirely new design, and capable of far superior results to anything achieved in the past.