US3726358A - Rotary loudspeaker - Google Patents

Abstract

A rotary loudspeaker system comprising, in combination, a rotatable loudspeaker and a reflector plate for reflecting sound radiated from the loudspeaker toward a listener. The reflector plate is located near the loudspeaker in such position that it does not interfere with the rotating movement of the loudspeaker and at such angle that it reflects the sound radiated from the loudspeaker toward the listener. The reflector plate is formed by a part of a cabinet in which the loudspeaker is housed. The angle of the reflector plate may be made adjustable. The reflector plate may be closed to form a completely enclosed cabinet.

Description

United States Patent 11 1 Kaisha, Shizuoka-ken,- Japan [22] Filed: Apr. 14, 1971 [21 Appl. No.: 133,972

30 Foreign Application Priority Data Apr. 17, 1970 Japan....' ..45/36689 Apr. 14, 1970 Japan ..45/36690- [52] US. Cl. ..181/31 A, 181/27 A, 312/7 R. [51] Int. Cl ......Gl0k 13/00, H04r H28 [58] Field of Search ..l8l/27 A, 31 B, 31 A;

[5 6] References Cited UNITED STATES PATENTS 2,622,693 12/1952 Leslie "181/27 A 2,642,948 6/1953 Olson et ..181/3l B 3,070,660 12/1962 lppolito ..l81/27 A 3,483,945 12/1969 Michael ..1s1/27 A Hiyama Apr. 10, 1973 15 ROTARY LOUDSPEAKER 3,500,953 3/1970 Lahti ..1s1 31 B [75] Inventor: Ryu Hiyama, Hamamatsu-sh i, FOREIGN PATENTS OR APPLICATIONS Shizuoka-ken, Japan 85,979 1191 B 1 1 73 Assignee: Nippon Gakki Seizo Kabushiki 7 I 6 Great 8 mA Primary Examiner-Stephen J. Tomsky Attorney-Henry T. Burke, Robert Scobey, Robert S. Dunham, P. E. l-lenninger, Lester W. Clark, Gerald W. Grifiin, Thomas P. Moran, R. Bradlee Boal, Christopher C. Dunham and John F. Scully ABSTRACT closed to form a completely enclosed cabinet.

5 Claims, 8 Drawing Figures PATENTED 01975 3; 726,358

SHEET 1 [1F 5 INVENT OR PW fi/ m/m BY A'IT RNEY PATENTEDAFR 1 01915 SHEET 2 OF FIG. 6

FIG. 7

INVENTOR BY f ATT NEY ROTARY LOUDSPEAKER BACKGROUND OF THE INVENTION The present invention relates to a rotary loudspeaker system for an electronic musical instrument or the like.

A complicated musical effect which would be produced by concurrently applying modulations in amplitude, frequency arid phase to the sound which radiates from a loudspeaker by rotating the loudspeaker, is generally called a tremolo effect. Such an effect is produced by variation of sound volume according to continuous change of radiating direction of the loudspeaker relative to a listener, variation of phase of sound wave, variation of frequency due to Doppler effect, or the like.

FIG. 1 shows an example of a rotary loudspeaker 1 which is usually housed in a tone cabinet 8 including a rear plate 9, a top plate 10 and a base plate 2. In order to simplify the description, the rotary loudspeaker without the tone cabinet will be explained with reference to FIG. 2.

Referring to FIG. 2, the rotary loudspeaker 1 is mounted on a shaft which is journalled on a pair of suitable brackets 4, which are fixed on a base plate 2 by bolts 3 or the like. The driving force for rotating the loudspeaker 1 is applied from a motor 7 through a belt 6 to a pulley I3 fixed on the shaft 5.

It is assumed that a listener is positioned in the direction designated by an arrow A. When the rotary loudspeaker l is rotated in the direction designated by an arrow E, the sound volume which reaches to the listener from the rotating loudspeaker may be generally considered to be maximum when the front side of the loudspeaker 1 comes to face toward the direction A, minimum when it comes to face toward the opposite direction designated by C, and medium when it comes to the transverse directions designated by B and D. The difference between the maximum and minimum values is considerably large. When the variation of the sound volume reaching to the listener during a period of the rotation to the loudspeaker is extremely large, the rotary loudspeaker gives uncomfortable effect to the listener, rather than providing comfortable tremolo effect. Accordingly, the rotary loudspeaker is usually combined with a suitable reflector means in order to reduce the extreme difference in sound volume. The reflector means may be constituted by a tone cabinet or a room itself in which the rotary loudspeaker is used. Such a reflector means, however, has some disadvantages.

The tone cabinet 8 housing the rotary loudspeaker 1 as shown in FIG. 1 has been most commonly used as a reflector means. Assuming that the listener is positioned at the left side of FIG. 1 and the loudspeaker I rotates in the direction E, it may be considered that the sound volume reaching to the listener becomes maximum when the front side of the loudspeaker l faces toward the listener, minimum when said front side faces toward the top plate 10 or the base plate 2 of the cabinet 8, and medium when it faces toward the rear plate 9 of the cabinet 8. In such construction, the

during a period of the rotation of the loudspeaker is still large so that satisfactory tremolo effectof the rotary loudspeaker I cannot be obtained. Particularly when the listener is not properly positioned relatively to the cabinet 8, that is, the listener is not positioned in the position immediately forward of the rotary loudspeaker, the reflecting effect due to the rear plate 8 and the top plate 10 of the cabinet 8 is considerably reduced.

Where the cabinet 8 has no top plate and the ceiling of the room, in which the rotary loudspeaker l is placed, is used as a reflector means, if the room has a high ceiling or a flat ceiling, the reflecting effect may be reduced, so that the sound may not be satisfactorily transmitted to the listener. That is, the effect to be obtained by rotating the loudspeaker is increased or reduced, depending on the shape of the room in which the loudspeaker is placed.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the disadvantages of the rotary loudspeaker as explained above.

In accordance with the present invention there is provided a rotary loudspeaker system which comprises a rotary loudspeaker and a reflector plate which is located near the loudspeaker in such a position that it does not interfere with the rotating movement of said loudspeaker and which is arranged in parallel relationship with a rotating axis of said rotary loudspeaker at such angle that it reflects the sound radiated from the loudspeaker toward a listener.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of a tone cabinet housing a conventional rotary loudspeaker, a side plate of said cabinet being removed to illustrate arrangement of said loudspeaker.

FIG. 2 is an enlarged schematic side view of the rotary loudspeaker shown in FIG. 1.

FIG. 3 is a fragmentary, schematic side view of a tone cabinet housing a rotary loudspeaker according to an embodiment of the present invention, a side plate of said cabinet being removed to show the arrangement of said loudspeaker.

FIG. 4 is a schematic side view, similar to FIG. 3, showing another embodiment of the present invention.

FIG. 5 is a view, similar to FIG. 4, showing a further embodiment of the present invention.

FIG. 6 is a fragmentary schematic side view showing a modified form of a groove or rail shown in FIG. 5.

FIG. 7 is a schematic side view, similar to FIG. 5,

v showing a further embodiment of the present inventremolo effect is somewhat improved, compared to the tion, including two reflector plates.

FIG. 8 is a view similar to FIG. 4 and showing another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS.3 through 7 illustrate several embodiments of the present invention. Through these drawings, same numeral designates same or similar part.

FIG. 3 shows a first embodiment of the present invention, in which a rotary loudspeaker 1 is driven in the direction designated by an arrow E (or in the opposite direction) on a shaft 5, which is journalled on .a pair of brackets 4 fixed on a base plate 2 by means of bolts 3. The driving force for rotating the loudspeaker is supplied from a motor 7 through a belt 6 to a pulley 13 mounted on the shaft 5. A listener is positioned at the left side of the loudspeaker, as viewed in FIG. 3. A reflector plate 11 is provided in such position that it does not interfere with the rotating movement of the loudspeaker 1 and at such direction or angle that it most effectively reflects the sound radiated from the loudspeaker 1 toward the listener. In the embodiment as shown in FIG. 3, the reflector plate 11 is fixed between a pair of side plates 12 by means of bolts, screws or like suitable fastening means at an angle, such that a left portion'of a top plate 10 is inclined upward. The reflector plate 11 may be movably mounted so that the direction relative to the listener may be adjusted as desired. In this embodiment, the reflector plate 11 is shown as mounted outside of the cabinet 8, but it may be supported within the cabinet by means of the base plate 2 or other suitable supporting structure.

In the construction of the loudspeaker provided with the reflector plate as shown in FIG. 3, when the loudspeaker 1 is directed upward (the sound volume would be reduced to minimum if the top plate 11 were posi- 27 which are pivotally connected together at 26. The link 27 is pivotally mounted at its end on a side plate 12 of the cabinet 8. Thus the movable top plate 21 is movable from the position as shown in FIG. 3 to the position where the movable plate becomes flush with the fixed top plate 20, by folding said links 25 and 27. Although the movable top plate 21 is shown as movable between the FIG. 4 position and the flush position, said plate may be positioned in an intermediate position between said positions if the links 25 and 27 are made adjustable in length.

In this embodiment, the sound of the loudspeaker can be effectively reflected toward the listener during a period of rotation thereof. The position of the loudspeaker 1 relative to the listener can be relatively freely selected, that is, the cabinet 8 containing the rotary loudspeaker 1 is not necessarily positioned at same height as the listener and may be mounted at high ground. Even when the loudspeaker is arranged in a large hall, it can direct the reflected sound toward the listener as desired, and thus the effective tremolo effect can be obtained, independently of the structure of the room in which the loudspeaker is placed. The reflector plate may be made by a part or whole of the top plate of the cabinet and it can be closed so that it does not form tioned as shown in FIG. 1), the sound volume is not so 1 reduced due to the reflection by the reflector plate 11 that the extreme variation of sound volume is not produced. It has been found that the best result can be obtained when the inclining angle of the reflector plate relative to a line directed to the listener is within a reflecting effect rapidly decreases. This is due to narrowing of the range in which the reflection of the sound of the loudspeaker by the reflector plate 11 effectively reaches to the listener.

By providing the reflector plate combined with the rotary loudspeaker, it becomes possible to substantially freely select the relative position of the loudspeaker and the listener. The reflector plate can efi'ectively reflect the sound radiated from the loudspeaker along the line directed to the listener, thus giving comfortable tremolo effect to the listener and producing as remarkable effect as if the number of the rotary loudspeaker were doubled. This is similar to the manner in which a mirror produces a virtual image. This loudspeaker can be constructed with simple addition of the reflector plate having desired size and shape, and consequently it can be manufactured without appreciable increase of manufacturing cost.

FIG. 4 illustrates another embodiment which is substantially similar to that shown in FIG. 3, except that a reflector plate is adjustably mounted on the top of a tone cabinet. In FIG. 4, a top plate of the tone cabinet 8 comprises a fixed top plate 20 and a movable top plate 21 pivotally connected to said fixed top plate 20 by means of a hinge 22 or the like. The movable plate 21 is provided adjacent its free end with a bracket 23, to which is pivotally mounted at 24 a series of links-25 and an obstruction. Thus the cabinet can be very conveniently transported. FIG. 8 illustrates a loudspeaker cabinet wherein the entire top plate 21a of the cabinet is a reflector plate. The cabinet shown in FIG. 8 is substantially similar to the cabinets shown in FIGS. 3 and 4; the only difference is that the entire top plate 21a of the'cabinet is a movable reflector plate, as opposed to the reflector plates 11 and 21 in FIGS. 3 and 4 respectivelywhich comprise only a portion of the top wall of the cabinets shown in FIGS. 3 and 4.

- FIG. 5 illustrates another embodiment in which the top plate comprises a fixed plate 30 and a movable plate 31. The movable plate 31 has pins 32 at its opposite sides, only one of the pins 32 being shown in FIG. 5. The pins 32 are slidably and pivotally received in a pair of grooves or rails 33 provided on a pair of side plate 12 of the cabinet 8. The pin 32 may make frictional engagement with the groove 33 or the side plate 12 with suitable friction by the aid of a spring or the like in order to prevent accidental motion of the pin in the groove.

The movable plate 31 has a recess (not shown) at its side end, into which a stay 34 is removably and pivotally fitted- An adjusting member 35 for adjusting the length of the stay is fixed on the side plate 12. Said member 35 adjustably receives said stay 34 and is adapted to fixedly engage with the desired position of said stay. The position of the engagement between the stay and the adjusting member can be adjustably fixed by means of a set screw or the like. The member 35 is made rotatable according to the direction of the stay 34.

In the construction as shown in FIG. 5, the movable top plate is adjustable not only in its inclining angle but position of the movable top plate acting as a reflector is further increased.

- FIG. 7 illustrates a further embodiment which comprises, in addition to the reflector plate formed by the movable top plate 31 as shown in FIG. 5, a second reflector plate formed by a movable front plate 36 which is supported at 32A on the side plate 12 of the cabinet 8 by means of a stay 34A and an adjusting member 35A in the same manner as in FIG. 5.

By the provision of the second reflector plate, the tremolo effect of the rotary loudspeaker l is further increased. When the reflector plates are not used, they can be closed to form a completely enclosed cabinet, thereby preventing foreign material from entering into the cabinet.

I claim:

1. A rotary loudspeaker system comprising a rotary loudspeaker, means for rotating the loudspeaker about a defined axis of rotation, a cabinet housing and supporting the loudspeaker and the means for rotating the loudspeaker, said cabinet including a top plate and a side plate, said top plate includinga first reflector plate for reflecting toward a listener sound radiated from the loudspeaker, and said side plate including a second reflector plate for reflecting toward a listener sound radiated from the loudspeaker, said first and second reflector plates disposed adjacent the loudspeaker but spaced from the rotary path thereof, said first and second reflector plates defining therebetween an opening in said cabinet for directing toward a listener sound radiated from the loudspeaker.

2. A rotary loudspeaker system as in claim 1 including means for adjusting the angle of at least one of said reflector plates with respect to the rotary loudspeaker.

3. A rotary loudspeaker system as in claim 1 wherein at least one of said reflector plates has an open position at which it is at an angle with respect to the cabinet plate which includes it and a closed position in which it is flush with the same cabinet plate.

4. A rotary loudspeaker system as in claim 1 wherein each of the reflector plates is at an angle of between 15 and 45 with respect to the cabinet plate which includes it. 1

5. A rotary loudspeaker as in claim 1 wherein the loudspeaker axis of rotation is in the horizontal plane and wherein each of said reflector plates is in a plane which is at an oblique angle with respect to the horizontal plane, and wherein the top and side plates have portions which are, respectively, horizontal and vertical.

Claims (5)

1. A rotary loudspeaker system comprising a rotary loudspeaker, means for rotating the loudspeaker about a defined axis of rotation, a cabinet housing and supporting the loudspeaker and the means for rotating the loudspeaker, said cabinet including a top plate and a side plate, said top plate including a first reflector plate for reflecting toward a listener sound radiated from the loudspeaker, and said side plate including a second reflector plate for reflecting toward a listener sound radiated from the loudspeaker, said first and second reflector plates disposed adjacEnt the loudspeaker but spaced from the rotary path thereof, said first and second reflector plates defining therebetween an opening in said cabinet for directing toward a listener sound radiated from the loudspeaker.

2. A rotary loudspeaker system as in claim 1 including means for adjusting the angle of at least one of said reflector plates with respect to the rotary loudspeaker.

3. A rotary loudspeaker system as in claim 1 wherein at least one of said reflector plates has an open position at which it is at an angle with respect to the cabinet plate which includes it and a closed position in which it is flush with the same cabinet plate.

4. A rotary loudspeaker system as in claim 1 wherein each of the reflector plates is at an angle of between 15* and 45* with respect to the cabinet plate which includes it.

5. A rotary loudspeaker as in claim 1 wherein the loudspeaker axis of rotation is in the horizontal plane and wherein each of said reflector plates is in a plane which is at an oblique angle with respect to the horizontal plane, and wherein the top and side plates have portions which are, respectively, horizontal and vertical.

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