Patent GB-942610-A (GB)
Title: Apparatus for translating sound into correlated physical effects
IPC: A63J5/10
Filed: 1961-08-31
Abstract: 942,610. Lighting effects. R. V. O'REILLY. Aug. 31, 1961. No. 31352/61. Heading A6M. [Also in Division H4] Apparatus for translating sound into correlated physical effects comprises an input circuit for sound, a plurality of frequency channel units connected to the input circuit, each unit including a filter for accepting and passing through a different portion of the frequency content of the sound, a plurality of electrical loads each individual to one of the frequency channel units, circuit means extending from the output of each of the frequency channel units to its corresponding electrical load, control of amplitude of the physical effect exhibited by each of the loads being generally in accordance with the variation in amplitude of the frequency components passed through the units and means interposing decay control in each of the frequency channel units for effecting a delay in fall off of the amplitude of the corresponding physical effect as the amplitude of the audio frequency content appertaining to such unit falls off. The circuit comprises a master input control 33 to which a microphone or transducer 23 and or alternatively a high level external signal 24 such as an electronic musical instrument are or is connected. The master input control comprises a preamplifier 38 with automatic gain control 39, in series with a microphone gain control 10 connected to an external audio gain control 11 in series with the external signal. At very loud levels the automatic gain control prevents continuous illumination and unresponsiveness of the lamps and at low levels allows light modulation. The output is connected to three channels having band-pass filter 40 passing the range 150-1500 c/s. with a peak at 640 c/s., high-pass filter 44 passing frequencies in excess of 1000 c/s. and low-pass filter 48 passing frequencies less than 250 c/s. connected to three lamps 29, 30 and 31, blue, yellow and red, housed within a cylindrical translucent shade. The channels contain the same circuit components except for the circuit of the triode V 2  of the filter units which is different for each channel in order to pass the different band widths. A channel gain control 13 for blending each light with the others is connected to the band-pass filter 40, an amplifier triode stage 41, and rectifier 42 which charges a selected capacitor of the group 71, 72 and 73 through attach control 16 in parallel with decay control switch 19 which selects the capacitor and discontinues the time constant of the decay of voltage which is applied to the control grid of load control tube V 4  to eliminate flicker of the lights. The control resistance is connected to a tetrode or pentode tube V 4 , the plate of which is in series with the lamp 30 and voltage doubler rectifier 55. The voltage doubler consists of rectifying diodes 75, 76 and charging capacitors 77, 78 energized from a 115 v. A.C. supply by means of transformer 52 which also supplies current to the tube heater and bias control 21. The bias control is adjusted so that the lamps burn dimly under no signal conditions. Various screen resistive loads 56 of the tube V 4  may be incorporated to control the ratio of the amplitude of the physical effect and the amplitude of the frequency band. In similar apparatus controlling seven lights, a cathode follower is inserted after the audio mixer and seven band-pass channels are provided. The loads instead of coloured lights may be magnetic amplifiers, relays, solenoids, D.C. motors, reactors, electrolysis, electroplating, buzzers or alarm bells.