Patent GB-900245-A (GB)
Title: Improvements relating to electric music instruments
IPC: G10H3/20
Filed: 1958-07-28
Abstract: 900,245. Electrical musical instruments; rod vibrators. SCHULMERICH ELECTRONICS Inc. July 28, 1958 [May 5, 1958 (2)], No. 24279/58. Classes 13 and 88 (2). An electrophonic keyboard instrument has a plurality of tuned bars, rods or other tone generators, each such tone generator being associated with a respective key and so adapted that its first four partials can be in octave relationship. Each key may actuate first and second strikers and preferably also a third striker. The first striker is arranged such that the first and second of said octave partials are louder than the third and fourth partials (harplike tone) while the second striker is arranged such that the third and fourth of said octave partials are louder than the first and second partials (celesta-like tone). A control (e.g. a stop) is operable to determine whether the first or second striker comes into operation on depression of the appropriate key. A pick-up converts the mechanical vibrations of the tone generators into electrical signals. Preferably each key has three tone generators (rods) A, B, C, associated with it for producing partials, as shown in Fig. 4. Carillon tone is produced by striking rods A, B, C simultaneously, rod A being struck at point 50 along its length (Fig. 3) and rod C generating a " burst " output. Bell tone is also obtained by striking rod A alone at point 50 or by striking rods A and B simultaneously. If rod A is struck at point 51 harp-like tone is produced while striking it at point 52 produces celesta-like tone. Other sounds may be used by utilizing different combinations of rods. The resultant sound from the instrument may be controlled by combining the output voltages from the pick-ups associated with rods A, B, C in a voltage ratio controller 58A, Fig. 6, to provide an output in which these voltages occur in desired magnitude relationship. Tone generator.-Each rod 11, Figs. 1, 2, is suspended above a horizontal base 10. The support at one end is a thread 14 supported by posts 17, 18 and attached to a spring 15 carried by post 16. The rod is supported at its other end by thread 20 bearing against damping posts 23 and fastened to posts 21. A magnetic armature 27 on the rod co-operates with a pickup coil 28 fixed to the instrument frame. To provide the first four partials in octave relationship the rod has notches 12, 13 spaced from the rod ends by a distance equal to 0.195 to 0.205 times the rod length (see Specification 845,416). Tones corresponding to rods A and B may be obtained from one grooved rod of rectangular cross-section the ratio of its sides being equal to 2: 1 (see Specification 845,416). Stops.-Selective striking of the rods A, B, C is controlled by stop control 54, Fig. 6. Stopbuttons 32-37, Fig. 7, control solenoids 40 which move slides 62-66. Portion 62A, Fig. 8, of slide 62 has contacts 44C2, 44C2#, &c., which contact rockers 30C2, 30C2#, &c., by movement of the stop 32 and -depression of the key controlling the appropriate rocker. Fig. 8 shows rocker 30C2 and contact 44C2 in engagement (slide 62A and rocker 30C2 having been actuated). An electrical circuit including a common bus 60 is thereby completed to energize solenoid 80 which actuates the hammer for striking rod A of note C2.