The Cine Technician (1935-1937)

Dec, 1936-Jan., 1937 The Journal of the Association of Cine-Technicians 87 indicated by an attenuation in response of 12 db at 120°. The frequency response curve is seen in Figure 4 and is uniform over a wide range of frequencies. Neon Volume Indicator. This piece of apparatus was designed to provide a means of giving an accurate indication of the amphtude of modulated hght reaching the fihn when sound is being monitored at a remote position from the recorder. The essentials of such an instrument are that it be linear in response over the audio range of present recording, i.e. 30 to 10,000 cycles, and that the voltage applied to the input transformer be in exact relation to that provided for the recording galvanometer and also that the observed results give the peak values of the recorded signals. The instrument designed is shewn in Figure 5 and consists of a two-unit voltage stage and gain control, the output of which is fed to the grids of a phirality of acorn type tubes. In parallel across each tube is mounted a small neon lamp so that the operation of the lamp may be controlled by varying the impedance of its associated tube. From the schematic diagram of Figure 6, it will be noticed that voltage applied to each grid may readily be preset by means of the potential dividers, and the rotation of lamp illumination made to conform with the scale calibration which is marked in decibel levels between— 45 and -1-3 decibels. The neon indicator should prove of great assistance to technicians when set monitoring, re-recording, or in any position where conditions make it impossible to observe the modulated light beam. Improvements in Film Processing. The demand for better quality from sound films has caused intensive research to be applied to problems arising from conditions and plant used in the many phases of recording up to the time the film is presented in the cinemas. This work has co\'ered acoustic conditions in both studio and theatre, functioning of apparatus for recording FIG 3 The measured dnechonal roaponae ol the Type 77 A Micophone The wide angle ol pickup is a particulaily note worthy leatuie The two curves ate typical ol the response at high and low lieguencies tespectively Curves lot inleitcediate Ite and reproducing, loud speaker mechanisms, etc., so that at the present time the many limiting conditions to improved quality are rapidly disappearing. However, it is possible to have acoustical, electrical, and mechanical conditions almost perfect but still find anticipated good quality lost by faulty processing — most probably in the transfer of sound from negative to print. Film emulsions have been developed with better resolving power and with suitable speed for sound track exposures whilst development and printing plant and film control technique has also progressed to keep pace with current demands. KANDEM STUDIO LIGHTS Are used by all Leading Film . . Studios A complefe range of Silenf Arcs up to 300 amperes and incandescenhs up to 10 k.w. is available for Hire and Purchase ISO .Ampere Arc Spot. BRITISH MADE BY— KANDEM KANDEM ELECTRICAL Ltd. 769 FULHAM ROAD LONDON, S.W.6 'Phone : FULHAM 238719 Works : PARSONS GREEN. S.W.6 . THE CROWN THEATRE PROVIDES STUDIO PROJECTION SERVICE AT ANY TIME TO SUIT YOUR CONVENIENCE. TWO DOUBLE-HEADS, n FULL RANGE SOUND, g d MIXING PANELS FOR TRACKS, a n d SEATING FOR 100 PERSONS, d a a a 86 WARDOUR ST., LONDON, w.i Telephone Gerrard 5223 c 1