Patent GB-190303666-A (GB)
Title: Improvements in the Art of and Apparatus for Generating and Distributing Music.
Inventor: BOTTOMLEY WILLIAM
Filed: 1903-02-17
Granted: 1904-05-17
Abstract: 3666. Bottomley, W., [Cahill, T.]. Feb. 17. Instruments with sonorous plates, or in which telephone diaphragms are used to translate electric alternations s in a circuit into corresponding musical vibrations, the invention constituting a method of and apparatus for generating and distributing music electrically, and being a modification of that described in Specification No. 8725, A.D. 1897, the object being to improve the quality of the music, to facilitate the expression, to increase the number of subscribers' instruments that can be supplied with musical electrical vibrations from a single centralstation instrument, and to enable the subscribers to regulate independently the power of the musical sounds produced. The generating - instrument more particularly described resembles a pipe organ in that it has a number of keyboards, three manuals and a pedal keyboard, swells, means for altering the tonecolour or quality of the notes of a keyboard, and a dynamic manual or keyboard for governing the loudness of the tones. The electrical vibrations for the fundamental notes and the harmonics or partials up to the sixteenth are supplied preferably by inductor alternators, and the tuning is rendered unchangeable by the employment of toothed gearing for the shafts of the alternators. Figs. 1 and 2 show diagrammatically the electrical connections for one keyboard and one set or register of tones, Fig. 3 the electrical connections for the various orders of partial tones, for the keys corresponding to the successive octaves of one note of the scale, and Fig. 5 the electrical connections of one key in each keyboard. The principal set of alternators 2 have frequencies corresponding to the frequencies of the notes of an equally-tempered scale, and from them are derived the fundamental tones and the second, fourth, eighth, and sixteenth partials ; the supplemental set of alternators 3 give the third, sixth, and eighth partials ; and from the third set of alternators 4 are derived the fifth and tenth partials. The supplemental alternators in simplified instruments are omitted. For the tones of the middle and the higher compass, the alternators have rotating iron armatures or inductors, but for the tones of lower range, the alternators have disc armatures without iron in the air-gap between opposite sets of pole-pieces. Any suitable form or construction of alternator may be used. One form of gearing for the twelve pitch - shafts 1<a>, 1<b>, 1<c> . . . 1<k>, 1<l>, 1<m> of the ground-tone alternators is shown in Fig. 7, the shafts being arranged in four groups and driven from the shaft 8 by the electric motor 11, but numerous alterations and arrangements of shafts and toothed gearing may be adopted. The alternators may be similar, or the numbers of inductor teeth may differ, and the angular velocities be proportioned accordingly. When any key 45 of the keyboard, or other suitable switch or circuit - controlling device, is depressed, the appropriate alternator circuit is closed through the contact-spring 49, the screw 53, the bar 54, the primary coil 56, the switches 55 or 55<a>, and a common - return bar. The induced currents in the coils 58, 62 act on the secondary coil 63, and if one of the dynamic keys 67 be closed, the currents act upon the secondary coil 65, which, through the line wires 68, 69, transmits the vibrations to the vibrationtranslating devices or telephones 70. The switches 55, 55<a>, the rheostat 60, 61, and the dynamic manual constitute expression devices. One or more of such devices might be dispensed with. Impedance coils 120 are employed in the timbre or quality controlling device 55, 55<a>; the switches resemble the different draw stops of an organ. Crescendos and diminuendos are produced by the brush 61 and the coils 60. To alter the impedance gradually, the set of contact-fingers 61, Fig. 28, of unequal length is employed, these fingers being moved to desired positions in relation to the contact plates 130 by means of swell pedals. Each subscriber regulates the loudness of the music by means of the rheostat handle 73. Any suitable telephone may be used as a translating-device. Preferably a telephone and horn device is used. The telephone may have a permanent steel magnet, or an electromagnet may be used with exciting-coils supplied with current by a local battery. The impedance coils and the inductoriums may have iron cores or be without them. In large plant, the contact-springs 49, 49<a>, 49<b> ... are knife-switches making a sliding contact and operated by power mechanism that is controlled by the key. Modified and alternative constructions for synthesizing notes of the timbre required may be adopted, as also modified and alternative constructions of the timbre-controlling devices and of the expression-controlling devices. The mutual inductance subsisting between vibration - transferring and vibration - receiving circuits may be varied instead of varying the self-induction, or resistance, or both of the circuits, or the intensity of inductive action of one coil on another may be varied by varying the number of active turns in a coil, or coils screened by Foucault or eddy currents, or a third inductive circuit may be employed, or the impedance of the circuits may be varied by altering the capacities. Instead of using a number of armature windings corresponding to the different orders of partial-tones furnished by the alternator to notes of different pitches, vibrations may be supplied to the several circuits by transformers or inductoriums or by any suitable means. The alternators separately are not improved units, but their arrangement and combination with the toothed gearing and the various expression devices are such as to constitute a feature of the invention. The various toothed gearings suitable for driving the alternators may be used to give movement to the organization of rotatory rheotomes described in Specification No. 8725, A.D. 1897. The claims are restricted, broadly speaking, to the following features in the electrical music-generating apparatus or system:- The means for altering the timbre or quality of the tones, the use of a number of registers of circuits, the use of a number of sets of vibration-generating devices, and the derivation of sets of harmonics from single sets of vibration generators, each in combination with other parts of the apparatus or system.