US2198521A - Method and apparatus for electrically reproducing sound vibrations - Google Patents

Description

Apnl 23, 1940. R. o. WHITELEGG METHOD'AND APPARATUS FOR ELECTRICALLYREPRODUCING SOUND VIBRATIONS 4 Sheets-Sheet 1 V Filed March 7, 1939.

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0, WA? egg, BY 4 I A'TTORNEY,

Patented Apr. 23, 1940- um'rao' STATES. PATENT OFFICE METHOD AND APPARATUS I03 ml! OAILY,REPBODUOING SOUND VIBRA- TIONS mm 0. match. Him-twain. Application March '1, mo. semi No. 200,350

'2 Claims. 01. sis-1.14)

My invention relates broadly toan improved apparatus for electrically reproducing sound vibrations and more particularly to apparatus for,

tion remote from the pipes and remote from the console.

A further object of my invention is to provide a construction of tone generator for connection with the pipes of an organ or chimes or in association with vibratory reeds in a musical instrument by which electrical n m isgenerated in accordance with thvibrations generated by the musical instrument and the elec- I or to the tone cavity of a reed system for gen-' crating tones.

Still another object of my invention is to provide an electrical control system for coordinating the operation of the pipes of a musical instrument with electrical generators individual to each of the pipes for selectively generating electrical energy in accordance with the vibration of the pipes and reproducing the electrical energy in a position remote from the pipes.

A further object of my invention is to providea construction of electrical generators which may be readily attached to the organ pipes of existing organ installations for increasing the useful range of the organ by providing means for electrically reproducing sound from the organ in locations remote from the organ pipes with a high degree of quality and timbre and with accurate reproduction of pitch of the reproduced tones.

of an organ with the operation of the electrical Figure 1 is a schematic side elevational viewoi the pipes and .wind chest of a pipe organ equipped with the electrical generators of my invention;

nerating elec- 11g. 2 is a schematic plan view of the pipes and wind chest of a pipe organ illustrated in Fig. 1; Fig. 3 is anenlarged transverse sectional view in any representative position such as, for example, on'line 3-3 of Figs. 1 and 2 and showing the arrangement of the electrical generators with respect to the organ pipes and an associated sound reproducing system connected with the electrical generators; Fig. 4 is a tie view showing the control circuit for an organ equipped with the electrical generator system of with parts shown partially in side elevation taken my invention and showing the coordination of f I theorgan pipe controls and the electrical generators; Fig. 5 is a schematic view showing a modified form of my invention applied to chimes and illustrating the manner in which sound vibrations generated by the chimes may be electrically reproduced in a remote position; and Fig. 6 illustrates the application of my invention for electrically reproducing sound from a reed type instrument.

My invention is directed to an improved apparatus for electrically reproducing sound from vibratory pipes or reedswhere it is desired to locally increase the amplitude of the sound or where it is desired to transmit electrical impulses corresponding to the sound to any remote'position for reproduction at a distance. The apparatus of my invention permits the broadcasting of i an organ recital by space or wired radio for the faithful and accurate reproduction of the original tones at a remote station. I provide selecvibration of the air column in that particular pipe. The electrical generator is designed to efflciently respond to the tone frequencies of its associated pipe and the electrical circuit with which each tone generator is associated is designed to efficiently transmit the generated range of frequencies. The amplification system through which'the several electrical currents are transmitted is substantially uniform so that the wave form of the several tone generators may be uniformly amplified and transmitted through the amplification system and through a network to a transmission linelfor operation of a modulation circuit of a signal transmitter for broadcast over a wire line, or through a radio broadcast transmission system or directly to a sound reproducing system for electrically reproducing the tones generated by the several pipes. The system of m invention requires an electrical generator .individual organ pipes, a partial list of the names and various stops of which are as follows:

10%' Quint 8" Diapason 6%- 4 Sub tierce 51/31 1 4' Octave 3 3 Tlerce 2' Super octave 2% 1% Tlerce 1'- Fife Stri up 16' 4.-- Violone 10% Quint 8' Gamba 6% Sub tierc 5% Quint 4 Viol 3 Tierce 2%- Quint 1% Tlerce 1'- Fife Flute group i 16' Bourdon 10% Quint Bourdon 8' Bourdon 8' Harmonic flute 6%' Sub tierce 5% Quint 4 Flute 3%, Tierce-ilute 2% Quint flute 1% Tierce flute 1' Fife flute 1 Reed group 16' Double trumpet reeds 8' Trumpet reeds 8' Oboe reeds 8'- Cornopean reeds 8' English horn reeds 8' French horn reeds 8 Orchestral oboe reeds 8 Vox humana reeds 8 Clarinet reeds temps heretofore made in picking up organ re-' citals by variously positioned microphone circuits. Reproduction of pipe organ tones in a collective manner by either single or-multiple microphones or other device have, up to the present time been only partially successful. The average pipe organ covers a considerable cubic area which prevents a correct relative reproduction of tone frequency by a collective method, and due to many complex fundamental tone frequencies and overtones, only an average tone or power can be reproduced by a single pick-up device for-the whole instrument A performer at the console has to use special precaution to eliminate certain tonecolours to avoid microphonic disturbances,

and such tones as 16' Bourdons in many casesv fail to reproduce at all. Loud passages have to be damped to prevent further microphonic disturbances. My approach to the solution of the problem was to design a special means of conveying the tone frequencies to a pick-up device without interference with the pipe resonator, which is -designated as the portion of the pipe from the languid upto the extremity or node. A pipe res- (water to functionproperly will not tolerate any interference by attachment of equipment, the

pipe resonator'itself under power being a vibrant M factor expanding and contracting as the column of air moves in its passage in a complex manner of tone frequencies, so the problem was to find a means of conveying thetone frequencies-to a pick-up device, suitable to its own frequency without in anyway disturbing its own natural.

tone. The insertion of a tube in the languid has proven highly successful. All organ pipes sit loosely on what is termed the chest or soundboard supported in a vertical position by a rackboard, and each'is supplied with wind at its lower extremity. I By properly designing the'organ pipes and inserting a tube in the languid passing through the. wind supply chamber to a position independent of the pipe, easily detachable and remote from interference from adjacent pipes, the electrical reproduction of sound from the organ pipes becomes highly practical. In such a position in the languid of each pipe, the pick-up can only be very weakly affected by adjacent pipes and in any case the electromagnetic circuit is designed to remain open until a key closes the circuit, in which case the pick-up device functions as it is intended.

The electrical generators which generate the electrical energy in response to the vibratory air column in the pipes are of the magnetic type and consist of a pair of magnetic pole members having windings thereon and wherein the pole members are interconnected by horseshoe magnets formed from mixed quantities of iron, aluminum, nickel and cobalt having high and permanent magnetic properties. The permanent magnets which I employ in the electrical generators insure the continued operation of the electrical generators over an indefinite period of time. The magnetic properties of the material I .have se lected for the permanent magnet systems in the electrical generators are such that a permanent magnet formed from this material is capable of lifting 1250 times its own weight. The pole pieces are associated with. a diaphragm which is disposed immediately above the pole pieces and peripherally suspended in a suitable manner. The electrical generator is mounted with respect to a tube which extends into the organ pipe so that vibrations within the organ pipe are conveyed through the tube and directly impinge against the diaphragm. The sound vibrations from the organ pipe change the physical position of the diaphragm with respect to the pole members and modulates-the magnetic flux which threads the windings about the pole members due to the intense magnetic field from the permanent magnet system.- The modulations thus produced cause a change, in the current supplied to the input of the amplifier system when the electrical generator is selectively connected by operation of the console to the amplifier system for electrically 5 1 within the wind chest MI.

transmitting a tone. corresponding to. the vibrations within the organ pipe- Referring to the drawings in more detail, Figs. 1 and 2 schematically show'a pipe organ having two rows of pipes extending vertically from the wind chest. I have designated the pipes as I-34 and 10-91, inclusive; In" the side elevational view of Fig. 1 I have shown the front row of the pipes I, 3, 5,1 and3 with certain of the pipes illustrated partially in vertical section. The air under pressure from the fan blower isdelivered through wind supply pipe I to the air chamber Each of the organ pipes contains a tube I02 for conveying sound vibrations from the organ pipe to the electrical generator. The tube I02 is fixed in the languid of the pipe indicated at I03 and extends through the block I04 andis swaged therein as indicated at I05 forming an air-tight and shock-proof joint with the material of block I04. It is important that this juncture be absolutely airtight as the pressure from the air chest is delivered through the port I08 in block I05 and must be utilized in driving the organ pipe by passage through port I01 which concentrically surrounds the tube. I02. The'port I06 in block I04 registers with port I08 formed in the header I09 on the wind chest and leads to the port IIO extending into the air chamber IOI of ,the air chest. There are individual ports for the separate pipes, all leading to the air chamber of the wind chest IOI. For purposes of explaining the invention I have shown the port II 0 for serving pipe 9 and in the plan view in Fig. 2 I have shown port III serving pipe I0. Inorder to regulate the supply of wind to the pipes, separate valves are provided in the header I03 as indicated at II2,

I I3, etc. These valves are individually adjustable.

and control the supply of air from the airchamber of the wind chest IOI through ports H0, I08, I06 and I01 to the pipe 9 (for example).

tensive ports from the air chamber of the wind chest under control of a deflatable pneumatic pouch valve which I have indicated at H4. The

pouch valve II4 isnormally urged to a position closing the associated port IIO by spring H5.

The deflatable pneumatic pouch'is disposed imboth sides of the pouch valve H4 is equalized, as will be understood. The magnetically actuated valve I2I includes a pair of electromagnetic wind-- ings I22 wound on pole pieces I23 which control magnetic disc valve I24. A screen of metal ,I2Ia covers the electromagnets I22 with a port I2Ib therethrough communicating with the air chain-t of a radio transmitter or a wired radio transmitterfor effecting wide distribution of the organ the valve chamber I20. When windings -I 22 are' her in the air chest IM and by which air anatoenergized, the pole pieces I23 are magnetized-and attract disc valve I24, shutting off the air from the air chest IOI and opening port I25 which-per mits the exhausting of air from the air chamber IIS and the collapsing of the pouch valve II4 allowing air from the air chamber IOI to pass ceive a screw threaded cap I21 which serves to clamp in position the magnetic diaphragm l20 Each of the ports IIO, III, etc. admits air to the coex- I and I38 which are insulatingly supported with respect to the pole members I3I and I32 and with respect to the casing I26. A pair ofhorseshoe permanent magnets are mounted within casing I26 in magnetic circuit with pole members I3I and I 32. Only one of these horseshoe magnets I31 is illustrated in the drawings'as the complementary horseshoe magnet is in the forward port of the casing I26, not cut by the transverse section line. Suitable means for maintaining the permanent magnets in position are provided such as screw members I38 coacting with the kidney pieces I39. The permanent magnets employed have high magnetic propertiesand are construct? ed from an alloy of iron, aluminum, nickel and cobalt. The pole pieces'I3I and I32 are spaced below the diaphragm I20 and immediately beneath the sound conveying tube I02 so that sound vibrations from the vibrating air column in the organ pipeare directly conveyed through tube I02. for bombardment of the diaphragm I23. The gap bridged by the magnetic flux between the magnetic diaphragm I28 and the pole pieces I3I and I32 is varied in BCCOIdfiIlCx with the sound vibrations, thus changing the flux density threading the windings I33 and I34, and generating therein current impulses which are transmitted through the circuits I40 to the keying system designated generally at I in Fig. 3 and thence through the amplifying system designated generally at I42 for operation of the sound reproducer indicated generally at I43. Thus it will be seen that mechanical vibrations established 1 by vibrating air in the organ pipe impart movement to the diaphragm I20 effecting an electrical charge in the windings I33 and I34 which is amplified to operate an electrical sound reproducing system. Such vsystem may be located in a remote position so that it is possible to faithfully reproduce the organ recital at a point remote from the organ pipes. A listener within the area of the sound propagated by .the organ will hear the program directly from the organ and yet in some; remote locality the same program may be electrically reproduced. The remoteness in the position of the reproducing device may be indeliinitie as the control circuits from the electrical generators may control the modulating circuit recital. v Byway of illustration, I have indicated the various notes which are reproduced by the various pipes in Fig. 2.

, In Fig. 4 which shows the control circuit for thelo'rgan and electrical sound reproducing system, I have illustrated one of the keying circuits controlled by key I44. The contact system I45 controls the circuits through the chest magnets indicated generally at I2I while the contact system I46 controls the circuits through the electromagnetic windings I33 and I34 of the tone generators. I'have shown one complete key with fifteen stop controls. A mixing transformer I41 having a primary winding I48 and a secondary winding I49 is provided between the keying circuit and the input to the amplifier I42. A high impedance coupling circuit is provided between secondary winding I49 0! the mixing transformer I41 as indicated at I50. The power supply to the amplifier system is furnished through leads indicated generally at I5I. The mixing transformer has the primary'winding thereof tapped to resonate the input circuit of the amplifier at the frequency of the tone generator which is connected to the keying circuit. The circuits to the diflerent tone generators which produce diflerent notes extend from taps on primary winding I48 indicated at 0, 6', 8', II', I5, 22', 30, 40, 52', 64', 19', 91', 8', I46 and I8I'. The individual keying circuits are each provided with series connected resistors which I have indicated generally at I62. The power supply for the chest control magnets is obtained from generator I53 with filter system I54 connected therewith as shown. The fact that an individual electrical generator is functioned by each organ pipe enables the separately generated frequencies to be integrated in the input system of the amplifier for reproduction of sound with quality and timbre and pitch comparable to the originally generated sounds.

The two leads at I80 extending through individual resistors I52 to taps 0' and 6' on primary winding I48 are required for the reason that these circuits independently control and operate at tones having difierent strengths. The two leads on the I6 circuit at I80 provide for soft register number one and two at a louder strength, and similarly with the three leads'on the 8' line indicated at I8I, different amplitudes may be reproduced. These are musical interpretations of tone power. These tone strengths are obtained by using different ratings of resistors I52 in series in the line, as indicated in Fig. 4.

The system of my invention may also be employed in chimes of the kind illustrated in Fig. 5. A tubular chime has been shown at I55 suspended through link I56 from support I51. The lower end of the tubular chime I55 has a transversely extending central flange I58 thereon which is gripped by means of screw cap I21 which engages casing I26 and also supports magnetic diaphragm I28 in suspension between gaskets I29 and I30. The parts of the electrical generator have been numbered similarly to the parts illustrated in Fig. 3. The connections from the generator to the electrical sound reproducer are similar to the connections illustrated in Fig. 4; The striking mechanism for the chimes has been shown generally at I59, including a hammer I60 pivoted at I6I and having an armature I62 which is actuated by electromagnet I63 against the action of spring I64. The chime is struck when key I65 is operated closing contactor I66 disposed in series with generator I61 and with the winding of relay I68. The contactor I69 of relay I68 is arranged in series with winding I63 of the actuator I59. The power to the magnetic actuating circuit is supplied from the power source through leads I10.

In Fig. 6 I have shown a reed system in which tone generating reeds I1I are mounted adjacent a windchamber I12. Theair pipe to the wind chamber I12 is indicated at I13. A valve for the reed indicated at I1I is-illustrated at I14 normally pressed to closed position by means of' spring I15. Control link I16 extends from the valve I14 through systemof levers I11 to the control key I18. The electrical generator which is operated in accordance with the vibration of the air column in the tone cavity I19 is mounted adjacent an aperture I in the wall of the tone cavity I19. The electrical generator has the screw cap I21 thereof apertured at I8I, the said aperture registering with aperture I80 in the wall of the tone cavity I19. The magnetic diaphragm I28 is mounted intermediate suitable annular gasket members I29 and I30, as heretofore explained, and adjacent the pole pieces I3I and I32 associated with the electromagnetic windings I33 and I34 arranged in association with the permanent magnet system I31 within casing I26. The outputs .of the several electromagnetic windings I34 and I33 of the electrical generators associated with the various reeds are impressed upon the input of the amplification system I42 through coupling circuit I50 operating sound reproducing system I43.

The coordination of the individual pipes and the means for reproducing each pipe tone electronically, greatly increases the esthetic qualities and musical tone colour that can be expressed by a performer. Heretofore in simple organ mechanisms where. coupler controls are used on individual ranks of pipes having a fixed tonal power, severe limitations have been imposed on such coupler arrangements. However, by the coordination of the electromagnetic means of my invention, it is possible to accurately determine tone strength for such intervals as require either fundamentals or partials adjusted to obtain imitative tone colours, by the inclusion of electrical resistors I52 in series in the electromagnetic circuits. The electromagnetic circuits are designed to enable a performer to obtain several determined tonal strengths, for instance at 16 pitch two are provided as at I80 and again at B pitch three are provided as at I8I, permitting a flexible arrangement for a performer, which is not possible with only a simple organ mechanism as applied to method of general organ construction. In small instruments the coordination is invaluable, saving the necessity of specially constructed chambers, if it is not desired to hearthe pipes which produce tone frequency for transmission to a pick-up device. The elimination of several chambers can also be accomplished and the amplification system can be located at various positions, providing ample power,

whereas without the coordination method of my invention, it might be necessary to install many additional ranks of pipes. My invention is particularly applicable in meeting problems in large auditoriums, and in places normally unsuccessful for organ reproduction due to acoustical conditions, absorption and loss of tone power and interference in sound travel, particularly where installations are provided with chambers distant from the console and having a time lag that is detrimental to the proper technical interpreta tion of music by a performer. The coordination provided by my invention is an economy, while at the same time making possible a true reproduction of pipe organ tones.

It will be understood that the electrical generators may be secured in relation to the pipes ortone cavity in any suitable manner such as by means of detachable brackets by which the individual generators may be insulated or replaced. It will also be understood that in certain instances it is desirable to mount the electrical generators adjacent the tube of a pipe or at one side of the pipe in a position to receive a portion of the pressure diverted from the pipe through a tubular member having its inlet disposed withproduced by the pipes or reeds. It will also be understood that various methods of coupling may be provided between the input of the amplifier and the electromagnetic windings of the electrical generators.

I have illustrated my invention in certain of its preferred embodiments, but I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In combination with an organ chest having a multiplicity of pressure distributing ports extending therefrom, block members having ports therein aligned with the ports of the organ chest, organ pipes supported by said block members and provided with pressure passages connected with the ports in the block members, means for generating electrical energy associated with each of said pipes and depending from said block members, said means each including a. magnetic member vibratile in the field of an electromagnetic winding, means for conducting vibrations from each of said pipes independently.

through said block members to the vibratile member in the respective generating means, the electromagetic windings of each of said generating means being adapted for connection to sound reproducing means electrically reproducing tones corresponding to the tones generated by the respective pipes.

2. In combination with an organ chest having a multiplicity of pressure distributing ports extending therefrom, block members having ports therein aligned with the ports of the organchest, organ pipes supported by said block members and provided with pressure es connected with the ports in the, block members, tubular members extending into each of said pipes and projecting through the pressure es interconnecting the block members with said pipes and terminating exteriorly of said block members, and means for generating electrical energy mounted adjacent the exterior terminus of each of said tubular members, said means each including a magnetic member vibratile in the field of "an electromagnetic winding and individually ex- -action for an organ pipe, an electrical generator individual to the organ pipe and operable for converting the sound vibrations thereof into electrical energy. individual electrical controlmeans generator, and actuating means for said control means operative in common with respect thereto for simultaneously energizing said electromagnetic valve action for sounding said pipe and connecting said generator for supplying electrical energy corresponding to the sound vibrations of said pipe.

4. In combination, an organ pipe for sustaining a tone frequency under the action of pneumatic pressure supplied to the pipe and having a languid transversely positioned at the lower end of said pipe, a tubular member concentrically disposed within said pipe and fixed in the languid of said pipe with an inlet opening into said pipe and an outlet extending below said languid and terminating remotely with respect tosaid pipe, and an electrical generator adjacent the outlet of said tubular member and operative by pressure effects delivered through said tubular member from said pipe for generating electrical currents corresponding to the sustained tone frequency.

5. In a sound reproducing system, an organ pipefor sustaining .a tone frequency under the action of pneumatic pressure supplied to the pipe, a languid in said pipe, a tubular member concentrically disposed within said pipe and fixed in 6. In a sound reproducing system, an organ pipe for sustaining a tone frequency under the action of pneumatic pressure supplied to the pipe, a languid in said pipe, means for supporting said pipe, a tubular member extending into said pipe and fixed m said'languid with an inlet opening into said pipe and an outlet extending through said supporting means and having an end portion enlarged in diameter for securing said tubular member in said supporting means, and an electrical generator disposed adjacent the enlarged outlet of said tubular member and operative by pressure eflects delivered through said tubular member from said pipe for generating electrical currents corresponding to the sustained tone frequency produced when said pipe is sounded.

'I. In combination with a wind chest having a multiplicity of pressure distributing ports extending therefrom, block members having ports therein aligned with the ports of the wind chest, sounding means supported by said block members and provided with pressure w connected with the ports in the block members for producing tone frequencies under the action of pneumatic pressure selectively supplied to said sounding means from said wind chest, means for generating electrical energy associated with each of said sounding means and depending from said block members, said generating means each including a vibratile member, and means for conducting sound vibrations from of said sounding means independently through said block members to the vibratile member respective generating means.

RICHARD O.

in the 10

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