US3095467A - Sound generating means - Google Patents

Description

June 25, 1963 H. o. SCHWARTZ ETAL SOUND GENERATING MEANS 4 Sheets-Sheet 1 Filed Feb. 13, 1961.

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SOUND GENERATING MEANS 4 Sheets-Sheet 3 Filed Feb. 13, 1961 United States Patent 3,095,467 SOUND GENERATING MEANS Harold 0. Schwartz and Anthony C. Ippolito, North Tonawanda, and William V. Machanian, Niagara Falls, N.Y., assignors to The Wurlitzer Company, Chicago, 111., a corporation of Ohio Filed Feb. 13, 1961, Ser. No. 88,908 3 Claims. (Cl. 84-1.25)

The present invention relates to electronic musical instruments such as electronic organs, and more particularly to the production of musical sound from electronic tone signals.

One object of the invention is to provide new and improved means for producing musical sounds with controlled music-al effects from electronic tone signals.

Another object is to provide, for producing musical sounds with a vibrato effect from electronic tone signals requiring amplification, new and improved sound generating means comprising electronic amplifying structure and vibrato speaker means which are correlated with each other in a manner which provides for efiicient cooling of the amplifying structure as an incident to operation of the speaker means to generate sounds with a vibrato effect.

Another object is to provide improved sound generating means which responds to electronic tone signals to produce musical sounds with controlled vibrato or chorus effects in a highly efficient manner which effectively avoids distortion and acoustical interference with the production of sound.

Another object is to provide improved sound producing means which responds to electronic tone signals to produce musical sounds with resonance at one or more frequencies within the audio range which can be controlled independently of the acoustical resonance of the sound producing structure.

Other objects and advantages will become apparent from the following description of the exemplary embodiments illustrated in the drawings, in which:

FIGURE 1 is a perspective view of a sound or tone cabinet incorporating one exemplary embodiment of the invention;

FIG. 2 is a horizontal sectional view, taken along the line 2--2 of FIG. 1;

FIG. 3 is a fragmentary vertical sectional View, taken along the line 33 of FIG. 2;

FIG. 4 is a simplified diagrammatic illustration of the electronic circuitry used in producing the sound;

FIG. 5 is a perspective view of a sound or tone cabinet incorporating a second illustrative embodiment of the invention;

FIG. 6 is a vertical sectional view, taken along the lin 66 of FIG. 5;

FIG. 7 is a horizontal sectional view taken along the line 7-7 of FIG. 6; 7

FIG. 8 is a horizontal sectional veiw, taken along the line 8-8 of FIG. 6;

FIG. 9 is a perspective view of the rotary high frequency speaker and support assembly used in the tone cabinet of FIG. 5; I

FIG. 10 is a fragmentary sectional view taken with reference to line 1010 of FIG. 9;

FIG. 11 is a longitudinal sectional view of the rotor assembly, taken with reference to line 11-11 of FIG. 9; and

FIG. 12 is a diagrammatic illustration of electronic circuitry used in the second embodiment of the invention illustrated in FIG. 5.

Having reference to the drawings in greater detail, the first embodiment of the invention illustrated in FIGS. 1 to 4, and identified in FIGURE 1 by the number 10 operates .to provide musical sound with a controllable 3,095,467 Patented June 25, 1963 ICC 2 vibrato elfect from electronic tone signals requiring amplification. Such electronic tone signals are supplied from a suitable tone generator 12, FIG. 4, which may be a component part of an electronic organ.

All the structural components of the physical embodiment of the invention used in producing musical sound with a controllable vibrato effect from the electronic signals supplied by the tone generator 12 and requiring amplification are physically integrated together within a very compact sound or tone cabinet 14, FIG. 1, in a manner which provides for very efiicient operation of the sound producing means under very favorable operating conditions which enable all the structure to operate reliably and efiiciently over a long service life.

As shown, the sound cabinet 14 has a rectilinear shape. A horizontal partition 16 supportedwithin the cabinet 14 coacts with the cabinet to define a relatively large bass reflex chamber 18 underlying the partition, and a much smaller and relatively :thin high frequency chamber 20 located immediately above the partition.

A low frequency or bass speaker 22 is mounted inside the bass reflex chamber =18 and communicates directly with the external environment through an acoustical opening 24 in the adjacent sidewall 26 of the cabinet. A second acoustical opening 28 in the sidewall 26 connects the space within the bass reflex chamber 18 to the external environment.

A high frequency or treble speaker 30, which is used to generate high frequency sound without a vibrato effect,

18 coacts with the cabinet wall 26 to isolate the high fre- I quency speaker 30 from low frequency pressure effects produced wihtin the chamber 18 by the speaker 22, thus avoiding distortion of the operation of the speaker 30 by the speaker 22.

High frequency sound with a vibrato effect is generated within the vibrato chamber 20 by means of a sound generating rotor 40 which comprises a horizontal speaker support or arm 42 mounted within the chamber 20 for rotation about a vertical axis.

Two high frequency or treble speakers 44 are mounted on one end of the arm in radially spaced relation to the axis of rotation 46 of the arm. The rotor 40 is balanced by an adjustable counterweight 48 supported on the end of the arm 42 opposite from the speakers 44.

The rotor 40 is driven by an electric motor 50 which is connected through a small driving pulley 52 on the motor, a belt 54 and a large driving pulley 56 to the rotor. The motor 50 and pulleys 52 and 56' are designed to rotate the rotor 40 at a speed of approximately six and one-half revolutions per second which corresponds to a most desirable frequency for the vibrato effect to be produced in the sound generated in the vibrato chamber 20.

Having reference to FIG. 4, the electronic tone signals supplied from the generator 12 are amplified by an amplifier 60 and fed to a cross-over network 62 which separates the sound signals according to frequency. The low frequency sound signals are supplied to drive the low frequency speaker 22 in the bass reflex chamber 18. The high frequency signals from the cross-over network 62 are supplied to a three-position selector switch 64.

When turned to the vibrato position illustrated in FIG. 4, the selector switch 64 connects the high frequency output of the cross-over network 62 to only the two rotating speakers 44, thus energizing the speakers 44 while the stationary high frequency speaker 30 remains silent. The.

rotary motion of the speakers 44 effects modifications in the pattern of sound emanating from the speakers with the result that the sound as heard by a listener has a pleasing vibrato quality.

The sound generated within the vibrato chamber 20 passes out through acoustical openings 66 in the side of the cabinet 14.

Movement of the selector switch 64 to a second extreme position connects the high frequency output of the cross-over network 62 to only the stationary high frequency speaker 30, leaving the rotating speakers 44 silent. The efiect of this is to produce sound without any vibrato effect or without any chorus effect, which will be described presently.

Movement of the switch 64 to a third or chorus position connects the high frequency output of the cross-over network 62 to the rotating speakers 44 and also to the stationary high frequency speaker 30. With reference to FIG. 4, the chorus position of the switch 64 is between the two extreme switch positions previously mentioned.

It has been found that the production of high frequency sound by the rotating speakers 44 simultaneously with the production of high frequency sound by the stationary speaker 30 achieves a highly pleasing and most desirable musical effect in the over-all sound output of all the speakers, which effect can be most accurately described as a chorus effect. The vibrato effect in the sound emanating from the rotating speakers 44 harmonizes pleasingly with the sound emanating from the stationary speaker 30 without vibrato quality.

The selector switch 64 is mounted in a conveniently accessible position on the sound cabinet 14, to enable the user to produce a musical sound with or without either the vibrato effect or the chorus effect with which the system is capable of producing sound. It will be understood that the switch 64 can be installed in any other desired position which provides the greatest convenience to the user. The capability of the sound producing system to selectively introduce controlled vibrato or chorus effects into the sound produced, greatly increases the versatility and musical capabilities of the sound system.

The amplifier 60 used to drive the speakers inherently generates heat at a substantial rate which tends to heat up the amplifier structure to temperatures which can cause premature deterioration of the amplifier and create other difficulties. However, as shown in FIGS. 1 to 3, the amplifier 60 is housed within the compact cabinet 14 and integrated with the rotating speaker structure in a manner which effectively cools the amplifier, thereby maintaining within the cabinet favorable operating conditions which provide for efiicient and dependable operation of all the structure, including the amplifier 60, over a long service life.

Thus, as shown in FIG. 2, the speakers 44 carried by the arm 42 are cone speakers having axes substantially perpendicular to the arm 42 and faces which are generally parallel to the arm 42. Hence, upon rotation of the rotor 40, the rotor structure, including the speakers 44, serves as an effective air propelling vane which generates substantial currents of air in the immediate vicinity of the annular path of the speakers.

The amplifier 60 is mounted within the vibrato chamber 20 in close proximity to the annular path of the speakers 44 to be effectively cooled by the air currents from the moving rotor 40. As shown, the amplifier 60 is mounted alongside the rear wall or panel 70 of the cabinet which defines an opening 72 alongside the amplifier which allows cooling air passing over the amplifier from the rotor 40 to escape from the cabinet.

Structural components of the second embodiment of the invention illustrated in FIGS. to 12, which form counterparts of components of the first embodiment of the invention previously described, are identified by the same reference numbers with the addition of the sufiix h. In this second embodiment of the invention, which is identified generally by the reference number 80, a pair of low frequency or bass speakers 22w are mounted in f the bass chamber 18a formed in the lower portion of the tone cabinet 14a.

As shown, the two speakers 22a are mounted on a vertical speaker panel 82 forming a part of the cabinet 14a and located just behind a louvered front panel 84 of the cabinet. In this embodiment of the invention, a relatively thin high frequency chamber 20:: is defined in the top of the cabinet 14a between the top cover or panel 86 of the cabinet and an underlying support deck or transverse panel 88. The deck 88 is spaced somewhat above the horizontal partition 16a covering the bass chamber 18a.

The amplifier 60a is supported on the transverse partition 16a in immediately underlying relation to a large air cooling opening 5'0 defined in the deck 88. Amplifier cooling air is drawn into the space 92, FIG. 6, between the partition 16a and deck '88 through an opening 94 in a rear panel 96 of the cabinet 14a. Air entering the amplifier space 92 in the cabinet cools the amplifier and is exhausted up through the opening into the high frequency chamber 20a through the cumulative action of convection currents and the suction effect of the blower action of the high frequency rotor 40a mounted in the chamber 20a, as will presently appear.

The amplifier cooling air is drawn into the high frequency chamber 20a through the opening 90 and is discharged from the chamber 20a through openings 100 in the speaker panel 82 and through louvered openings 102, 104 in the front and side panels of the cabinet.

The rotor 40a is journaled for rotation between two horizontal plates 106, 108 of a rotor support frame 110 located within the high frequency chamber 20a and providing support within this chamber for the rotor driving motor 50a. It will be noted that the lower plate 108 of the frame 110 is spaced above the horizontal deck 88 to provide space for circulation of the amplifier cooling air rising through the deck opening 90.

As in the previously described embodiment of the invention, two rotary high frequency speakers 44a are supported on the rotor arm 42a in spaced coaxial rela tion to each other and in spaced relation to the axis of rotation of the arm 42a. The speakers 44a are cone speakers, approximately four inches in diameter, which are turned back to back to face in opposite directions.

It will be understood from the previous description that the rotating speakers 44a serve to generate high frequency sound with vibrato effects. The efiiciency with which this sound is produced and the quality of the sound are enhanced by interconnecting the two speaker 44a by a cylindrical shroud 112 which coacts with the two speakers to form a closed compression chamber 114, FIGS. 10 and 11, which effects an acoustical isolation of the adjacent sides of the two speakers 44a from the external environment. As shown, the pair of speakers 44a are mounted in and serve to close opposite ends of the cylindrical shroud 112. The pressure waves from the back or inner sides of the speakers 44a are effectively contained within the compression chamber 114 so as not to interfere with or distort the sound pressure waves emanating from the oppositely facing sides of the speakers.

Preferably, the cylindrical shroud 1 12 which extends between and serves as a support for the speakers 44a is attached to the adjacent end of the rotor arm 42a by means of a clamp band 116 embracing the cylindrical shroud and secured to the arm, as shown in FIGS. 9 to ll.

Two stationary high frequency speakers 30a are used in this embodiment of the invention. As shown in FIGS. 6 and 7, both speakers 30a are disposed within the high frequency chamber 20a and mounted on the speaker board 82 adjacent high frequency outlet openings 120 in the speaker board 82. The inner or back sides of the speakers 30a are acoustically isolated from the external environment by means of dome-like enclosures 122 secured to the panel 84 in enclosing relation to the back sides of the respective speakers, as shown in FIG. 7. The enclosures or acoustical isolating members 122 preclude interference with operation of the speakers 30a by pres-' sure fluctuations within the high frequency chamber 20a, While at the same time containing pressure fluctuations emanating from the adjacent sides of the respective speakers, so as to enhance the overall quality of the sound generated in the tone cabinet.

This embodiment, like the first embodiment of the invention previously described, is also adapted to produce sound with a vibrato eifect or with :a chorus eifect, or without either a chrous or vibrato effect, as desired. The switching means used to accomplish this will be described presently in greater detail.

Provision is made for introducing resonant effects in the sound produced by the tone cabinet 60 at one or more frequencies wtihin the audio range which may differ from the acoustical resonance of the tone cabinet structure.

It will be understood that the bass chamber 18a, as defined by the speakers 22a and the structure of the cabinet 14a, will have an acoutical resonance at a frequency dependent upon the size and other significant factors in the design of the chamber. Provision is made for electrically introducing resonance into the production of the sounds at audio frequencies other than the acoustical resonance of the physical structure of the tone cabinet.

As illustrated in FIG. 12, this is accomplished by incorporating an electrically resonant network 130 into the input for the amplifier 60a As indicated diagrammatically in FIG. 12, electronic tone signals are supplied from the tone generator 12a through an output conductor 132 which is grounded through a sixteen ohm resistor 134 in an electronic organ 136 which includes the generator 12a. The electrically resonant circuit 130 is mounted in the tone cabinet 80 along with the amplifier 60a.

In the network 130, the signal imput conductor 132 connects through two parallel circuit paths 137, 138 with a common output conductor 140. The output conductor 140 connects with the input of the amplifier 60a through a 220 kilohm resistor 142 and is connected to ground through a 100 kilohm volume control rheo'stat 144. The two circuit paths 137, 138 are designed to introduce resonance into the signals supplied to the amplifier 60a at resonant frequencies within the audible range.

Thus, the circuit path 137 comprises a 1.5 kilohm resistor 146 and a 27 kilohm resistor 148 connected in series between the conductors 132 and 140. A conductor 150, between the resistors 146, 148, is connected to ground through a grounded 82 kilohm resistor 152 and a 3.2 millihenry variable inductance 154, which is connected between the conductor 150 and the resistor 152 in parallel with a .33 microfarad capacitor 156 and a 100 kilohm resistor 158 connected in series with each other. The electrically resonant frequency of the circuit path 137 can be regulated to have a desired value, by adjustment of the variable inductance 154.

The circuit path 138 comprises a 1.5 kilohm resistor 160 and a 100 kilohm resistor 162' connected in series between the conductors 132, 140. A conductor 164, extending between the resistors 160, 162, is connected to ground through a grounded ohm resistor '166 and a 10 microfarad capacitor 168' connected between the resistor 166 and conductor 164 in parallel with a 150 ohm resistor 170 and a 750 millihenry variable inductance 172 connected in series with each other.

The resonant network 130 is normally used only in the production of organ sounds from tone signals supplied from an organ 136. A jack 174 provides for connecting other sources of electronic sound signals to the amplifier 60a independently of the resonant network 130.

As further indicated diagrammatically in FIG. 12, provision is made for controlling the generation of vibratory acoustical eflects in the sound produced, by means of a simple switch 180 on the organ 136, which switch is connected tothe tone cabinet through only two conductor.

wires 182, 18 4.

In the tone cabinet 80 the coils of three control relays 186, 188, 190 are connected in parallel between the conductor 184 and a conductor 192 extending to one side of a transformer output winding 194. A .1 microfarad capacitor 196 is connected in parallel with the relay coils. The conductor 182 is coupled with the conductor 192 through a 1000 microfarad capacitor 198, and connects through a rectifier 200 with the side of the power coil 194 opposite the conductor 192.

As further illustrated in FIG. 12, the output of the amplifier 60a is connected through a capacitor 222 with the switches 1884, 190-1 of the relays 188, 190, which switches are used to control driving of the stationary high frequency speakers 30a, and rotating speakers 44a, in accordance with the setting of the switch on the organ 136.

Movement of the switch 180 to a vibrato position disconnects the conductors 182', 184, deenergizing the relays 186, 188, and 190. This causes the switch 188-1 to move to the position illustrated, to effect energization of the rotating speakers 44a while the switch -1 deenergizes the stationary speakers 30a.

Movement of the switch 180 to its chorus position connects the conductors 182, 184 together through a switch resistor 224, to allow a buildup in voltage on the conductor 184 which is sufiicient to energize relay coil 190 to energize the stationary speakers 30a through relay switch 190-1.

Movement of the switch 180 to its Ofi position connects the conductors 182, 184 directly to each other to apply suflicient voltage to the conductor 184 to energize all three relays 186, 188 and 190. The switch 188-1 then deenergizes the rotating speakers 44a while energization of the speakers 30a is continued.

The relay 186 controls the generation of tremolo effects in the sounds emitted by the bass speakers 2211. When the switch 180 is in either its chorus or vibrato position the relay 186 is deenergized and the relay switch [86-1 energizes the speakers 22a through a variable inductance 226. The manner in which the inductance 226 is varied to introduce tremolo efiect-s into the sound forms no part of the present invention.

Energizati-on of the relay 186 when the switch 180 is turned to its Off position operates the switch 186-1 to energize the speakers 22a through a nonvaryin-g inductance 228.

The invention is claimed as follows:

1. For producing musical sound with a vibrato effect from electronic tone signals requiring amplification, a sound generating unit including a sound cabinet defining therein an amplifier chamber and a vibrato chamber located above said amplifier chamber and being separated from the amplifier chamber by a horizontal partition member, said cabinet defining a cooling air inlet opening into said amplifier chamber, said cabinet defining an outlet opening from said vibrato chamber for sound and heated air, an electronic amplifier mounted in said amplifier chamber, said partition member defining a chimney opening therethrough located above said amplifier to allow air heated by said amplifier in said amplifier chamber to rise upwardly into said vibrato chamber, a speaker support mounted for rotation within said vibrato chamber about a generally vertical axis, a speaker electrically coupled to said amplifier and being mounted on said speaker support in spaced relation to said axis about which the support rotates, a motor connected to rotate said speaker support to move said speaker thnough an annular path, said vibrato chamber having a height which is only a fraction of the diameter of the annular path of the speaker, and said chimney opening through said partition being located closer to the axis of rotation of said support than is said outlet opening from the vibrato chamber so that air rising through said chimney opening is propelled outwardly through said outlet opening by the rotating speaker and support.

2. For producing musical sound with a vibrato effect from electronic tone signals requiring amplification, a sound generating unit including a sound cabinet defining therein an amplifier chamber and a vibrato chamber 10- cated above said amplifier chamber and being separated from the amplifier chamber by a horizontal partition member, said cabinet defining a cooling air inlet opening into said amplifier chamber, said cabinet defining an outlet opening from said vibrato chamber for sound and heated air, an electronic amplifier mounted in said amplifier chamber, said partition member defining a chimney opening therethrough located above said amplifier to allow air heated by said amplifier in said amplifier chamber to rise upwardly into said vibrato chamber, a speaker support mounted for rotation within said vibrato chamber about a generally vertical axis, a hollow chamber member of generally cylindrical form carried by said speaker support in spaced relation to said axis about which the support rotates, two speakers electrically coupled to said amplifer and being fixed to opposite ends of the chamber member so that the chamber member and the speakers together form a closed chamber for acoustically isolating the two adjacent sides of the speakers from the external environment, a motor connected to rotate said speaker support to move said speakers through an annular path, said vibrato chamber having a height which is only a fraction of the diameter of the annular path of the speakers, and said chimney opening through said partition being located closer to the axis of rotation of said support than is said outlet opening from the vibrato chamber so that air rising through said chimney opening is propelled outwardly through said outlet opening by the rotating speakers and support.

3. For producing musical sound with a vibrato effect from electronic tone signals requiring amplification, a sound generating unit including a sound cabinet defining therein an amplifier chamber and a vibrato chamber located above said amplifier chamber and being separated from the amplifier chamber by a horizontal partition member, said cabinet defining a cooling air inlet opening into said amplifier chamber, said cabinet defining an outlet opening from said vibrato chamber for sound and heated air, an electronic amplifier mounted in said amplifier chamber, said partition member defining a chimney opening therethrough located above said amplifier to al low air heated by said amplifier in said amplifier chamber to rise upwardly into said vibrato chamber, a speaker support mounted for rotation within said vibrato chamber about a generally vertical axis, a speaker electrically coupled to said amplifier and being mounted on said speaker support in spaced relation to said axis about which the support rotates, a motor connected to rotate said speaker support to move said speaker through an annular path, said vibrato chamber having a height which is only a fraction of the diameter of the annular path of the speaker, said chimney opening through said partition being located closer to the axis of rotation of said support than is said outlet opening from the vibrato chamher so that air rising through said chimney opening is propelled outwardly through said outlet opening by the rotating speaker and support, said sound cabinet including means defining therein a bass chamber that is acoustically resonant at one or more frequencies, a bass speaker mounted in said bass chamber and electrically connected to said amplifier, and an electrically resonant electrical network interconnected with said amplifier to provide in the sound signals amplified by the amplifier resonance at one or more resonant frequencies within the audible range that are difierent from the frequencies at which the bass chamber is acoustically resonant.

References Cited in the file of this patent UNITED STATES PATENTS 2,489,653 Leslie Nov. 29, 1949 2,831,051 Teikowski Aug. 15, 1958 2,887,000 Leslie May 15, 1959 2,995,054 Leslie Aug. 8, 1961 FOREIGN PATENTS 780,810 Great Britain Aug. 7, 1957

Claims (1)

1. FOR PRODUCING MUSICAL SOUND WITH A VIBRATO EFFECT FROM ELECTRONIC TONE SIGNALS REQUIRING AMPLIFICATION, A SOUND GENERATING UNIT INCLUDING A SOUND CABINET DEFINING THEREIN AN AMPLIFIER CHAMBER AND A VIBRATO CHAMBER LOCATED ABOVE SAID AMPLIFIER CHAMBER AND BEING SEPARATED FROM THE AMPLIFIER CHAMBER BY A HORIZONTAL PARTITION MEMBER, SAID CABINET DEFINING A COOLING AIR INLET OPENING INTO SAID AMPLIFIER CHAMBER, SAID CABINET DEFINING AN OUTLET OPENING FROM SAID VIBRATO CHAMBER FOR SOUND AND HEATED AIR, AN ELECTRONIC AMPLIFIER MOUNTED IN SAID AMPLIFIER CHAMBER, SAID PARTITION MEMBER DEFINING A CHIMNEY OPENING THERETHROUGH LOCATED ABOVE SAID AMPLIFIER TO ALLOW AIR HEATED BY SAID AMPLIFIER IN SAID AMPLIFIER CHAMBER TO RISE UPWARDLY INTO SAID VIBRATO CHAMBER, A SPEAKER SUPPORT MOUNTED FOR ROTATION WITHIN SAID VIBRATO CHAMBER ABOUT A GENERALLY VERTICAL AXIS, A SPEAKER ELECTRICALLY COUPLED TO SAID AMPLIFIER AND BEING MOUNTED ON SAID SPEAKER SUPPORT IN SPACED RELATION TO SAID AXIS ABOUT WHICH THE SUPPORT ROTATES, A MOTOR CONNECTED TO ROTATE SAID SPEAKER SUPPORT TO MOVE SAID SPEAKER THROUGH AN ANNULAR PATH, SAID VIBRATO CHAMBER HAVING A HEIGHT WHICH IS ONLY A FRACTION OF THE DIAMETER OF THE ANNULAR PATH OF THE SPEAKER, AND SAID CHIMNEY OPENING THROUGH SAID PARTITION BEING LOCATED CLOSER TO THE AXIS OF ROTATION OF SAID SUPPORT THAN IS SAID OUTLET OPENING FROM THE VIBRATO CHAMBER SO THAT AIR RISING THROUGH SAID CHIMNEY OPENING IS PROPELLED OUTWARDLY THROUGH SAID OUTLET OPENING BY THE ROTATING SPEAKER AND SUPPORT.

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