US2033440A - Apparatus for the production of music - Google Patents

Description

March 10, 1936. B. F. MIESSNER 2,033,440

APPARATUS FOR THE PRODUCTION OF MUSIC Filed March 25, 1933 Z Z Z4 ATTORN Patented 10,1936- I 2,033,440

"UNITED STATES PATENT OFFICE- APPARATUS roa 'rnn rnonoo'rron or Music Benjamin F. Miessner, Millburn Township, Essex County, N. J., assignor to Miessner Inventions, Inc., a corporation of New Jersey M Application March 25, 1933, Serial No. 6Ii2,697

' 14 Claims. (Cl. 84-197) This invention relates to musical instruments bears on the top (right-shown side) of the bridge, v

employing a plurality of vibrators, and more pareach string I bears on the bottom (left-shown ticularly to those wherein electric currents are side) thereof. The strings themselves may form utilized in the process of translating their vithe sole support for the bridge, which is preferbrations into sound, ably a single one common to all the strings in 5 It is an object of my invention to provide an the pitch range of the instrument. improved instrument of the class described. A For setting each string I into vibration there further object is the provision of improved is providedahammer I2. These may be actuated means and methods for coupling the vibrators toby a conventional piano action. For damping 1O gether. A still further object is the provision of each string I may be provided a damper I4, actu- 1o improved means and methods for regulating the ated conventionally. rate of dampingof the vibrations of the vibrators. For translating the vibrations of each string I Other and allied objects will more fully appear into electric oscillations Ihave shown mechanicofrom the following description and the appended electric translating system beginning with a 15 claims. strip I5. This strip may have a narrow, elec- 15 In such description reference is had to the trically conductive surface 90 in slight spaced accompanying drawing, of which: relationship to a point .on each string I prefer- Figure 1 is a view, partly cross-sectional and ably a little forward of or above its contact with partly schematic, of an instrument embodying bridge In. This conductive surface 90 may be g my invention in one form, wherein tuned strings, electrically connected to the grid of a thermionic coupled together in a novel mechanical manner, vacuum tube I6, whose cathode may be energized are set into vibration by percussion, and their viin any suitable manner and whose anode cur brations are controllably damped and translated rent may be Supp d as m a po v p H into sound through the medium of electric osoilon high voltage vattery or other source iii, the

Ill/$10115; a negative terminal of which may be hereinafter 25 Figure 2 is an enlarged detail view of the bridge referred to as ground. The grid of tube I6 I0 and parts immediately adjacent thereto, inmay be maintained slightly negative with respect eluding surface 90. to the cathode by connection through high re- Reference being had to Figure 1, there will be sistance I9 to ground,.the cathode of the tube seen a string I and a string I, strung respectively being rendered slightly more positive than ground 30 from tuning pin 2 to hitch pin 3 and from tuning by virtue of anode current flow through conpin 2' to hitch pin 3. The tuning pins may pass densively by-passed resistance 20. In the anode through clearance holes in plate portion 4 into circuit of tube I6 may be provided in cascade wrest plank 5, and the hitch pins may be reamplifier 2|, volume control or potentiometer 22,

tained in insulating bushings 5 and these in turn further amplifier 23, and loudspeaker or other set into plate portion I. Each string may pass electro-acoustic translating device 24. All the under capo or pressure bar 8, and may be eleestrings I are for ordinary purposes connected trlcally insulated from capo 8 and frame portions through the upper-shown blade of switch 25 to 4 and 1 by insulating members or strips 9. It the positive potential of high voltage battery I8.

will be understood that the plate portions 4 and They may thus be said to be polarized-i. e., 40 I and capo 8 may each be part of an integrally maintained at a high potential difference from east plate or frame, or may be otherwise rigidly the mean potential of the conductive surface 90 or interconnected, according to common piano practhe grid of tube I6. At the same time the strings I may conveniently be groundedi. e., main- 5 While only one string I and one string I have tained unpolarized. been illustrated, it will be understood that there The functioning of the translating system may will be employed at least one string I tuned to be best understood by observing that between each note in the pitch range of the instrument. each string I and the conductive surface of strip A similar number of strings I, similarly tuned II a small electrostatic capacity exists. These 59 if desired, may be employed, but this number capacities in parallel with each other form a 59 and'condition of strings I' maybe-varied actotal capacity from strings to strip; and this cording to principles hereinafter set forth. A capacity is charged through resistance I9 to the bridge i0 is provided, to which all the strings potential of source I8. Because of the high value are engaged as by conventional bridge pins I I. of this latterresistance this charge cannot change It will be seen, however, that while 68.91 string l r pidly. If now any string I be set into vibra- 55 tion toward and away from the strip I5. as results from striking by its associated hammer I2, the capacity from the string to the strip will be varied in accordance with the frequency and Waveform of the point of the string opposite the strip; and the total strings-to-strip capacity will be likewise varied, though in reduced degree. By virtue of the relative constancy of the charge in this capacity, the voltage across it will vary correspondingly. The oscillation variations in this voltage are applied to the grid of the tube It and are thereby and by amplifiers 2| and 23 amplified, may be controlled in respect of amplitude by volume control 22, and are finally translated into sound by loudspeaker 24. It will be appreciated that any slight capacity from the conductive surface 90 to strings I will not be charged as long as strings I are not polarized, and that vibratory variations in this capacity are therefore not effective in producing electric oscillations or sound.

While the mechanico-electric translating system disclosed operates upon an electrostatic principle, my invention is not limited to the use of translating systems of this type, since it will be obvious that other types of mechanico-electric translating systems, such for example an electromagnetic, are equally capable of employment therewith.

Referring more particularly to the bridge Ill, supported solely by its engagement with the strings, it will be seen that strings I' take the place of the more conventionalbridge support comprising a resonator, or of the alternative support comprising substantially non-radiating wooden ribs as disclosed and claimed in my copending application Serial Number 573,319, filed November 6, 1931 (on which U. S. Patent 1,929,029 has now been issued). Their substitution for these other forms of coupling media oiiers certain advantages of control, in that for varying degrees of coupling the number, size and tension of the strings I' may be variously chosen. Additionally, if the strings I are respectively tuned to frequencies identical with or harmonically related to the frequencies of certain .of the strings I-preferably those engaging the bridge near such respective strings I'-the advantage of generation of extra high frequency vibrational components and their reaction on the strings I is obtained. This effect is aided by proportioning the length of each string I, from its point of engagement with the lower-shown bridge pin I I to its point of engagement with the'insulation 9 on plate portion 1, asan integral fraction of the length of the same string from its point of engagement with the upper bridge pin II to its point of engagement with insulation 9 on capo 8.

If provided in-number and pitch corresponding to those of adjacent strings I, the strings i' may be employed for the generation of tones rela-' tively free of percussion components according to principles set forth in my co-pending application 'Serial Number 583,613, filed December 29, 1931.

Under these conditions when a string I is set into vibration as by its associated hammer I2,.the coupling existing by virtue of bridge I0 between that string I and the adjacent similarly tuned string I will transfer a portion of the vibratory energy of the string I to the string I'. This transfer is not instantaneous, however, andthus the string I will go into vibration with a gradual, rather than abrupt, initial amplitude rise. If now the vibration of a point on the string I,

preferably near its rigidly supported (uppershown) end, be translated into sound, this sound will resemble rather the tone of the organ or a like instrument than a piano or other percussion tone. I have therefore shown a mechanicoelectric system for translating these vibrations of the string I into electric oscillations, from which of course they may be translated into sound.

This system comprises a strip I5 similar to the previously described strip IS, with narrow conductive surface 90' in slight spaced relation to the strings I near their points of engagement with insulation 9 on capo 8. This strip may conviently be mounted, as by rigid strips 26, to capo 8. The conductive surface 9! may be connected to the grid of tube I8 through switch 21, by the selective manipulation of which this connection may be efiected either alternatively or additionally to the like connection to the grid of the conductive surface When strip I5 is substituted for strip I8 by switch 21, switch 25 may be reset (downwardly one contact) so that it grounds strings I and polarizes strings I. This charges the capacity between the conductive surface and the strings I', and renders it effective in translating the vibrations of strings I' into electric oscillations. The strings I being unpolarized, their capacity to the surface 90 is ineffective in producing electric oscillations.

It may be noted that with the surface 90 alone connected by switch 27 to the grid, switch 25 may be further re-set to its down-most position, polarizing both the string I and the strings I and charging capacities from strings to both strip surfaces. Again, switch 21 may be set to connect both strip surfaces II and II to the grid, and switch 25 in this case employed to polarize either strings I, strings I', or both strin s I and 1 strings I. These various possibilities of switch settings aflord various tone characteristics, both in respect of abruptness of tone inception and of harmonic structure, the latter being influenced of course by the position or positions along the strings from which translation is effected.

When strings I' are translated from it is desirable that each damper ll, normally provided for a string I, be made simultaneously operative on the similarly tuned string I, and the dampers have been so illustrated in Figure 1.

The inherent effect of a string supporting sys- ."4

tem of the type described is that of coupling the strings together without exerting an appreciable damping influence thereon. The tones produced by the instrument as thus far described may therefore tend to have an abnormally slow rate of damping. For damping the vibrations of the strings I have shown a damping system associated with the bridge I0, it being understood that this system is not limited to use with-the particular form of bridge and supportabove described. This damping system comprises a member 28, which may conveniently be in the form of a long strip, ofhigh electrical conductivity, firmly secured as by bars29 to the bridge III at frequent points along the latter. Through this strip at frequent points along its length may be maintained astrong, steady magnetic field. Thus! have shown in Figure 1 an electromagnet 30, which may be rigidly mounted, with its poles II in close proximity to and on' respectively opposite sides of member 28.

This electromagnet, of which it will be understood a plurality may be employed, may b cited by a strong electrical current, preferably direct, as from battery or other source II. A

ling device may control the strength of the fields maintained by the electromagnets through member 28.

The operation of this damping means depends on the induction of currents in a conductor upon motion of the latter in a magnetic field. When any of the strings are vibrated the bridge II is likewise vibrated, principally in a horizontal direction as shown in Figure 1. Member 28 consequently vibrates in and out of the gap formed by the poles 3|, and electric currents are consequently induced therein. These currents produce a power loss in the form of heating of member 28, and this power loss represents energy originally abstracted from the strings and not returned to them. This energy loss suffered by the strings increases their rate of damping. The strength of the currents induced in the member 28, the power loss in this member, and hence the rate of damping of the strings, increase with the strength of exciting'current supplied to the electromagnets, and hence with a decrease of the resistance of 32. The latter therefore provides a means of control of the rate of damping. It will be understood that alternatively the member 28 may be rigidly mounted and the electromagnets 30 secured to the bridge.

It will be appreciatedthat the foregoing deing all of said strings and supported solely thereby.

,3. In a musical instrument, the combination of two groups ,of tuned vibrators, and mechanical coupling means interposed between the respective vibrators of said two groups and solely supported by said vibrators.

4. In a musical instrument, the combination of two groups of tuned strings, and a bridge interposed between the respective strings of said two groups and supported solely by said strings.

5. In a musical instrument, thecombination of two groups of tuned vibrators;. mechanical coupling means interposed between the respective vibrators of said two groups and supported solely thereby; means for exciting vibrations of the vibrators of one of said groups; and means for translating into sound the resulting vibrations of the vibrators of the other of said groups.

6. In a'musical instrument, the combination of two groups of tuned vibrators; mechanical coupling means interposed between the respective vibrators of said two groups and supported solely thereby; means for exciting vibrations of the vibrators of one of said groups; and means selective with respect to said two groups for translating vibrations of the vibrators thereof into sound.

7. In a musical instrument, the combination of a group oftuned strings, a bridge against one face of which said strings bear, a second group of tuned strings bearing against a face of said bridge opposite said first mentioned face, selective means for exciting the strings'of said first group whereby to initiate gradually rising vibrations of strings of said second group, and means for translating electric oscillations from said last mentioned vibrations.

8. In a musical instrument, the combination of a group of tuned strings, a bridge against one face of which said strings bear, a second group of tuned strings bearing against a face of said bridge opposite said first mentioned face, said bridge being fioatingly held between said two groups of strings, selective means for exciting the strings of said first group, and means for translating electric oscillations from vibrations of the strings of said first group.

9. In a musical instrument, the combination of a group of tuned strings, a bridge against one face of which said strings bear, a second group of tuned strings bearing against a face of said bridge opposite said first mentioned face, means selective with respect to the several strings of said first group for producing vibrations thereof whereby to initiate gradually rising vibrations of strings of said second group, and means selective with respect to said two groups of strings for translating electric oscillations from their said vibrations.

10. In a musical instrument, the combination of a plurality of tuned vibrators, a vibratile bridge engaging said vibrators. and electromagnetic means associated with and influencing said bridge for damping said vibrators.

11. In combination in a musical instrument: a tuned vibrator and means for exciting the same into vibration, and means, including electrically conductive member and means for maintaining thereth'rough a strong magnetic field, for damping saidvibration.

12. In combination in a musical instrument: a tuned vibrator and means for exciting the same into vibration; means, including an electrically conductive member and means for maintaining therethrough a strong magnetic field, for damping said vibration; and means for varying the strength of said field.

13. In a musical instrument, the combination of a plurality of tuned vibrators, a vibratile bridge engaging said vibrators, and means for damping said vibrators, said means comprising an electrical conductor and means for maintaining a stron magnetic field through said conductor,

one of said two last mentioned elements being mounted to said bridge and the other being rigidly mounted, whereby said conductor is vibrated relative to said field upon vibration of said bridge.

14. In a musical instrument, the combination of a plurality of tuned vibrators, a vibratile bridge engaging said vibrators, and means for damping said vibrators, said means comprising an electrical conductor, means for maintaining a strong magnetic field through said conductor, one of said two last mentioned elements being mounted to said bridge and the other being rigidly mounted, whereby said conductor is vibrated relative to said field upon vibration of said bridge, and adjustable means for varying the strength of said field.

BENJAMIN I MIESSHER.

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