GB928337A - Artificial reverberation apparatus - Google Patents

Abstract

928,337. Artificial reverberation devices. HAMMOND ORGAN CO. June 15, 1959 [Oct. 13, 1958], No. 20418/59. Class 40 (4). [Also in Group XL (b)] A device for obtaining a reverberation effect comprises at least one coil spring 40, Fig. 1, connected between two transducers 36, 37, said spring being in two parts connected in series and wound in opposite directions. Transducer 36 converts an electrical audio-frequency input signal into mechanical vibrations. These vibrations travel along the spring 40 as torsional oscillations, are reflected from its ends to derive the reverberation effect and are converted into electrical signals at transducer 37. Other coil springs 41, 42, also in two parts of opposite hand, are in parallel with spring 40. The two parts are joined at their lower ends by a sleeve 48, Fig. 6. The springs 40, 41, 42 are loosely suspended between the transducers and for shipment may be clamped by inward movement of a metal strip 66. Rubber strip is cemented to the metal strip 66 and to the adjacent part of the frame to prevent damage to the clamped springs. Clips 110 serve to retain the springs when the apparatus is tilted. The lower end of the device floats between springs 32. Transducers.-Each transducer 36, 37 comprises a U-shaped laminated core 100, Figs. 3, 4, and a pair of signal coils 106. Between the pole faces of the core 100 are magnets 96, e.g. of ferrite. The magnets 96 are supported by wires 90 and each magnet 96 is connected by a hook 94<SP>1</SP>, Fig. 5, to the end of a spring 40 &c. Damping washers 84 differing in thickness from one to another embrace the wires 90. System.-Electrical signals from a source 120, Fig. 10, which may be an electrophonic organ, a microphone, a gramophone or a tape recorder are amplified in amplifier 122 and part of the output signal is fed to loud-speaker 124 while the remainder is applied to the reverberation device 126 and then to an amplifier 28 and loud-speaker 130.