Exhibitors Herald World (Oct-Dec 1930)

42 Better Theatres Section November 22, 1930 shutters are provided for, as it should be in every projection room. The Bradleystat used for our stepless monitor volume control is connected in series with the speech coil of the horn unit. The ideal mounting position for the Bradleystat is on one side of the fader box, where a suitable hole may MONITOR ouiTijt f>— Monitor speech J/60 OHrrj y COIL ,C^ Monitor volume control setup. be drilled in order to allow the shaft to protrude so that the operating knob may be fastened 'to the outside. The shaft is surrounded by an outer threaded bushing, which also will protrude through the hole in the box. The tightening down of a locknut then fastens the whole unit in position. This device is, in our case, in connection with the output of Western Electric number 46-B amplifier. We urge that in no case this or any other device be connected into this equipment without at first receiving the approval of this company's service engineer. "We know that you are mentally digesting the idea of applying this principle to the control of the main horn input, thus securing stepless fader adjustment and incidentally getting away from poor contact in f aders, which latter trouble is sometimes encountered. With the carbon disc pressure for adjusting resistance, stepless control is obtained, but it must be pointed out that as we use it there is no contact with the fader. The Bradleystat merely cuts out resistance to the monitor speech coil, regardless of the fader setting. "We believe the idea of applying this principle to the fader proposition is worthy of consideration. "A photograph of our motor generator set, with its coil spring suspension and the necessary switching arrangement to interchange with the rectifier, is enclosed. (Also, a view of the theatre interior, executed by Projectionist Ward, than whom, as a photographer, there is no whomer.) You will note the iron switch rack containing main and individual switches for the motor generator and the emergency mercury arc rectifier. There also is a box containing a three-pole cartridge cut-out, where the moving of a fuse out of one fuse clip into another provides instantaneous connection of arcs to either the motor generator or the rectifier. There too is the ballast resistance for the two projectors and the stereo, all compactly mounted. "RETURNING for the moment to the photograph of the projection room emergency lighting arrangement you will see the toggle snap switch, its holding cord and a section of the shutter suspension bar, all clearly shown. The large switch box upon which is is mounted is not the magnetic switch but merely another switch, which was already in place, so that we used it as a support for the snap switch and tension spring. The conduit above the large switch shown afforded us an easy means for bringing the two wires for the snap switch into position. The magnetic switch, which was mentioned at some length, prior to this, is located outside of the projection room. Returning now to the carbon-resistingfader-control proposition, there may be some difficulty in applying this to the main horn control, because the variable pressure in a device of this kind may make it difficult to bring a given volume to a given fader setting (as shown on the dial) twice in succession, the adjustment being so very fine. However, so long as the monitoring of the main sound can be done for monitoring purposes, the dial as it now is would be unnecessary, except for purposes of making a record." I present this to you, gentlemen, just as it is received. The devices I saw in Coil spring suspension of the emergency lighting setup, with switching and metering rack, also rheostats in position. Cranbrook worked perfectly. I would advise that you study these drawings and photographs, because they are worthy of it. The suspension of the motor generator is an adaptation of the plan set forth in this department and in the Bluebook years ago. A heavy plank is suspended by ropes, which as I remember it, are attached at their upper end to iron hooks, the hooks passing up through the main support attached to the iron frame and through a coil spring upon which the supporting nut at the top rests. The motor generator stands on the boards. The springs absorb all the vibration and you can hardly hear a sound. GENERAL CONDITIONS IN PROJECTION TODAY I HAVE before me a letter from the office suggesting that I write an article describing projection conditions as I found them on my nation-wide tour this summer. Now I don't mind a suggestion from the head office when it is a good one, and this one is so very good that I will act upon it. Projection conditions throughout the country, while they show a tremendous advancement over conditions of some 13 years ago, when I made my last trip, may still be very greatly improved, particularly with regard to sound. Insofar as has to do with motion picture projection, sound has almost entirely eliminated the curse of over-speeding. With sound, it just can't be done, at least to any very damaging extent. The principal fault now encountered is travel ghost and under-illumination. As I have explained to you, travel ghost is very harmful, because of the evil effect it sets up on definition by slightly blurring the horizontal lines of the picture, and by pulling the whites up or down over the blacks, which, of course, in the very nature of things, reduces the contrast of the picture. While it is true that the blurring effect above mentioned may be very slight, still it is there, and it makes the picture hard on the eyes of the theatre patron — especially on such eyes as are very sensitive to such things. I have found that pictures without any travel ghost at all are the exception, though it is true that in many theatres the ghost will be so slight that one must go down to the forward seats to see it. A great many believe that such a small ghost does no harm, but such a conclusion is very erroneous and one which