GB408998A - Improvements in or relating to electrical musical instruments - Google Patents

Abstract

408,998. Electrical musical instruments. JACKSON, L. MELLERSH-, 28, Southampton Buildings, Chancery Lane, London.-(Vierling, O. ; 7, Kloedenstrasse, Berlin.) Sept. 21, 1932, No. 26276. [Class 88 (ii).] In a musical instrument wherein the vibrations of tuned bodies which are fixed at least at one end, e.g. strings, are electrostatically translated into electric oscillations operating a loud-speaker or the like, the electrostatic strip, e.g. 76, Fig. 1, which forms a capacity with the strings is made so narrow as to pick up oscillations from substantially only a point on each string, and crosses the strings in a regular manner. A strip 76 may divide all the strings in the same ratio (Fig. 2, not shown) or may run parallel to one end of the strings (Fig. 3, not shown). Means are described for mingling in various proportions and in the same or opposite phases, vibrations taken by a number of strips 76 ... 80 placed at different points along, and above or below, the strings (the vibrations at the different points containing different proportions of harmonics) so as to obtain any desired timbre. Strips 76, 77, 78 are connected respectively to valves 84, 85, 86 and by means of switches 81, 82, 83, may be associated with or substituted by strips 79, 80 on the other side of the strings. The combined outputs of these valves are amplified at 103, 104 and delivered to loud-speaker 105, being mixed in the desired proportion and phase by closure of selected switches of banks 98, 99, 100 connected on either side of the centres of tapped resistors 95, 96, 97, the centres of which are connected as shown. For instance, combination of the strips 76, 80 alone with similar amplitudes and aiding phase of the fundamental produces vibrations without the even partials. If the fundamental phases are opposed, the octave is produced. The switches may be operated by tablets like the stop-keys of organs. A tone-control device, comprising an inductance 109 and capacity 110, with potentiometer 111, may be used with amplifier 103 to attenuate the lower partials of bass tones, or the higher partials of treble tones as desired. Similar frequency-discriminators 108<1> may be used with the valves 84, 85, 86, producing further tonal effects. Electrostatic shielding 106 may be provided.