Tremolo effect producing system
United States Patent 1191 Suzuki Apr. 8, 1975 TREMOLQ EFFECT PRODUCING SYSTEM Primary ExamineF-Kathleen H. Claffy Assistant E.\&#39;aminer-Douglas W. Olms 75 Inventor: Shoichi S k&#39;, H t. J I 1 um I amama w apan Attorney, Agent, or F1rmCushman, Darby &amp; [73] Assignee: Nippon Gakki Seizo Kabushiki Cushman Kaisha, Shizuoka Japan [21] Appl&#39; 375913 A tremolo effect producing system comprises, in combination, a closed housing, an electro-acoustic trans- [30] Foreign Application Priority Data ducer such as a loudspeaker supported in said housing July 15. 1972 Japan 47-71101 for revolutions a Plane and capable convening electrical audio signal to an audible sound, a plurality [52] Us. 61 ..179/1J of accustc-electric transducers such as microphones [51] Int. Cl. H02p 5/00 Provided at different PositionS in said housing to face 581 Field of Search 179/1 J; 84/] .25; said sleeve-acoustic transducer successively as the 181/31 3] B, 3] R latter is rotated and capable of converting audible sound to an electric signal, and at least one electro- [56] References Cited acoustic transducer such as a loudspeaker disposed UNITED STATES PATENTS outside said housing and connected to the output side 7 7 of said acousto-electric transducers via means for con- A trolling the magnitude of the output signals of said fl 41969 acousto-electric transducers and via at least one amh 6/197 plifier connected to said controlling means so as to be 5 10/197] driven by the amplified signals of said outputs.  
 665 10 I197 Chownmg l79/l J 9 Claims, 10 Drawmg Figures M I M /@l 4 1 11 4.10 g z A 6 j &#39;--&#39;=1 D g V v12 z 4 o i 15 j SP 13 000 1 o f l/l/l/l/l/l I ///I [1/ FATEHTEC 81975 3,876,834 I sum 1 o 3 FIG. 1 FIG. 4  
 PRIOR ART PRIOR ART I V /I Z I g i Fl G. 2  
 PRIOR ART F G. 5  
 PRIOR ART FIG.3  
 TREMOLO EFFECT PRODUCING SYSTEM BACKGROUND OF THE INVENTION a. Field of the Invention The present invention-relates to sound reproducing systems for producing tremolo effects. and, more particularly, to novel tremolo effect producing systems most suitable for use with electronic musical instruments.  
 b. Description of the Prior Art As the conventional sound reproducing system for producing a tremolo effect on sounds as they are generated by an electronic musical instrument, there is known the type having a rotational disc located in front of a loudspeaker or speakers to thereby provide a tremolo effect, as disclosed in, for example, Japanese Utility Model Publication No. 22436/1965 and US. Pat. No. 3294722.  
  Said Utility Model Publication, as shown in FIG. 1, discloses a tremolo effect producing apparatus comprising a motor I. a rotational shaft 2 operatively connected with the motor, an acoustic reflecting plate 3 of which the center is supported by the end of the shaft so as to be rotatable in any plane involving the shaft, a bearing 4 slidably engaged with the shaft 2, a connecting lever 5 connecting the bearing 4 with the side portion of the reflecting plate 3, and a loudspeaker 6 in front of which is located the reflecting plate 3 so as to face it. whereby the sounds from the speaker provides a tremolo effect through the reflecting plate as the plate is rotated with respect to the direction of the shaft. namely. axially of the loudspeaker.  
  Said US. Pat. as shown in FIGS. 2 and 3, discloses another system for generating a tremolo effect on the sound waves from speakers including a sound reproducing speaker enclosing cabinet, a vertically disposed speaker supporting panel spaced inwardly from an open side of the cabinet, a plurality of sound reproducing speakers 6 mounted on the panel, a rotating disc 7A spaced from and operating in a plane parallel with the speaker supporting panel and having openings corresponding in diameters with the diameters of the diaphragms of the speakers or a rotating plate 78 having cutouts and a motor for rotating the disc or the plate at a required revolution speed.  
  Other known device of the type in which a plurality of speakers are rotated in a plane to produce a tremolo effect is referred to in the following two US. Pats. That is, US. Pat. No. 3,100,024, as shown in FIGS. 4 and 5, discloses an apparatus for producing vibrato or tremolo effects, comprising a motor I, a drum 8 arranged on the inside of a peripheral wall on which a plurality of speakers 6 are revolvably mounted for rotating about an axis, the drum being operatively connected with the motor through a belt so as to be rotated. and slip rings R through which low frequency currents are supplied to the respective speakers, whereby the sounds from the speakers are given vibrato or tremolo effects as the speakers are horizontally rotated in the same plane with that of rotation of the drum driven by the motor.  
  As shown in FIG. 6, US. Pat. No. 3,084,585 indicates an acoustic modulator comprising a speaker mounting disc 9 having circumferentially disposed plural speakers 6 which may be rotated about a horizontal axis, namely, circumferentially by means of a suitable motor MA and may be rotated about a vertical axis of a vertical standard 1C, namely, perpendicularly to the vertically diametric direction of the disc, by means of another motor MB, to produce a Doppler effect and a tremolo effect.  
  However, these known tremolo effect producing systems having the following disadvantages.  
  First, the known tremolo effect producing apparatus are inconveniently bulky, occupying large space and complicated in mechanism and are impossible to effectively produce a tremolo effect when reproduced by means of headphones in an electronic musical instrument. Furthermore, when incorporated in an electronic musical instrument, such an apparatus generally requires a fixed loudspeaker for sound reproduction having non-tremolo effect, as well as a rotating loudspeaker for providing a tremolo effect, and also separate power amplifiers therefor.  
  Accordingly, such an apparatus not only tends to be very expensive but also are impossible to radiate&#39;tremolo and non-tremolo sounds from the same speaker, resulting in the lack of naturalness of sound in the performance of the electronic musical instrument.  
 Summary of the invention Therefore. it is an object of the present invention to provide a novel tremolo effect producing system, which is able to eliminate the abovementioned defects and which is widely adaptable as an electro-acoustic modulator.  
  A further object of the present invention is to provide a tremolo effect producing system which is small in size or space-saving and is inexpensive to manufacture, and is able to dispense with a conventionalloudspeaker which has been used only for obtaining a tremolo effect in an electronic musical instrument.  
  A still further object of the invention is torprovide a system for producing a tremolo effect which is adaptable for a headphone as a sound reproduction system of an electronic musical instrument and will impart the sounds from the headphone with a tremolo effect having a sufficient depth.  
  Another object of the present invention is to provide a sound reproduction system with a specific tremolo effect producing housing member for generating an audio signal electro-acoustically modulated with a tremolo effect, which comprises, in combination, a closed housing, an electro-acoustic transducer such as a loudspeaker supported in said housing for revolutions in a plane and capable of converting an electrical audio signal to an audible sound, a plurality of acoustoelectric transducers such as microphones provided at different positions in said housing to face said electro acoustic transducer successively as the latter is rotated and capable of converting audible sound to an electric signal, and at least one electro-acoustic transducer such as a loudspeaker disposed outside said housing and connected to the output side of said acoustoelectric transducers via means for controlling the magnitude of the output signals of said acousto-electric transducers and via at least one amplifier connected to said controlling means so as to be driven by the amplifled signals of said outputs.  
  Other objects, features and advantages of the present invention will become apparent from the following detailed description of some specific embodiments thereof when taken in conjunction with the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 through 6 are views illustrating conventional tremolo effect producing means by way of examples.  
  FIGS. 7 and 8 are partially sectional views. respectively, for showing an example of the essential part of an embodiment of the present invention.  
  FIGS. 9 and 10 are schematic diagrams showing a couple of examples of the manner in which the present invention is used.  
 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to to the present invention, there is provided a unique tremolo effect producing system which is useful in, for example, electronic musical instruments, which system is arranged so that a loudspeaker is supported at, for example, the central part ofa closed box or housing for being rotated in a plane, and that a plural number of microphones are provided, for example. one at each corner within the housing to pick up the sound produced from the rotating speaker and imparted with tremolo effects, and that the outputs of these microphones are amplified and reproduced outside the housing. This tremolo effect producing system provides more realistic tremolo sounds also when a head-phone is used with this system.  
  Referring to FIGS. 7 through 10, description will be made with respect to some embodiments of the present invention.  
  In FIGS. 7 and 8, there are shown a partially sectional plan view and a partially sectional side view of an example of a tremolo effect producing unit according to the present invention to show a basic construction. which comprises in combination: an acoustically sealed, closed square housing 10 as viewed from above which is somewhat rectangular in shape when viewed from its side; a rotatable shaft 11 provided at a substantially central part within said housing 10; a loudspeaker SP and a balancer 12 both of which are secured to said shaft 11 in a direction normal thereto: a pulley 13 is mounted on the lower part of said shaft 11; a motor provided in said housing; a belt 14 applied between this motor 15 and said shaft 11 to rotate the shaft 11 and the loudspeaker SP as well as its balancer l2. Arranges ment is provided so that low frequency currents are supplied to the loudspeaker SP via a brush 16 and slip rings R. The aforesaid basic construction further comprises microphones M. M, which are provided at the respective corners within the housing 10 to face the central part of the space in this housing to be able to pick up, respectively, the sound waves produced from the loudspeaker SP. These main parts described above constitute the tremolo effect producing unit which is indicated generally at T.  
  This tremolo effect producing unit T may be used, for example, in either of the&#39;following ways.  
  As a first example which is shown in FIG. 9, the output of the program source 17 pf, for example, an electronic musical instrument is first amplified by an amplifier 18. This amplified output is then applied to the rotating loud-speaker SP contained in the tremolo effect producing unit T via the terminal t, to thereby generate sound waves within said housing 10 from said rotating loudspeaker SP. The varying sound waves produced from the rotating loudspeaker SP are then picked up by the microphones M, M, which are provided at the respective corners of the housing 10. Then, the outputs of these microphones M, M, are mixed appropriately through variable resistors VR VR VR and VR, which are provided outside said housing 10, and the mixed output signals are amplified by an amplifier 20 which is also provided outside the housing 10 and these amplified sound signals are emitted as audible sounds from a fixed loudspeaker SP which is provided outside the housing 10. These audible sounds when listened to are imparted with realistic tremolo effects which give natural feeling to the listener. A head-phone 21 may be attached to the output of the amplifier 20 via a jack J. In this case, the user of this head-phone 21 is able to enjoy equally interesting tremolo sound waves through the head-phone 21.  
  In FIG. 10, there is shown another example of use of the tremolo effect producing units T of the present invention. In this example in the same way as is done in the preceding example, the output side of the amplifier 18 is connected to the terminal t of the tremolo effect producing unit T. The output of this amplifier 18 is applied to the rotating loudspeaker SP contained in said unit T to cause varying sounds of waves to be produced within the housing 10. The resulting tremolo sounds are picked up by the respective microphones M, M, in exactly the same way as described above. The output signals of these microphones are passed, via variable resistors VR -VR and via amplifiers 20 -20,, independently of each other, which are serially arranged to said resistors, respectively, to loudspeakers SP -SP which are provided at the respective corners within the listening room L. By doing so, it is possible to produce a further interesting tremolo effect.  
  In each of aforesaid examples, low frequency currents such as those of the outputs of, for example, an electronic musical instrument are supplied to the loudspeaker SP contained in the housing 10, while rotating this loudspeaker SP at a speed of the order of 0.5-l5 revolutions per second. Whereupon, the input sound waves of the respective microphones M, M, are imparted such tremolo effect as are corresponding to the rotation speed of the loudspeaker SP contained in said unit T. Accordingly, the outputs of these microphones give tremolo signals. These tremolo signals are supplied to either a loudspeaker SP or loudspeakers SP,-SP or to the headphone 21 after being amplified by the amplifier 20. There can be heard such sound waves whichv consist of the sounds of the program source after being imparted tremolo effects.  
 It should be understood, however, that the presentinvention does not contemplate direct listening to the sounds radiated from the loudspeaker SP contained in the housing. Therefore, this loudspeaker SP may have a small size and accordingly the housing itself also may be compact in size.  
  As stated above, according to the present invention, a loudspeaker is rotatably provided in a housing such as a closed box, and the sound waves produced from this loudspeaker after being imparted tremolo effects caused by the rotation of said loudspeaker are received by the microphones. At the same time, another loudspeaker or loudspeakers are driven by the amplified signal of the output signal of said microphones, thereby obtaining sounds having tremolo effects. Thus, by the use of a housing and a loudspeaker having a small size, it is possible to acquire such tremolo effects that give natural feeling which has never been experienced before. Moreover, according to the present invention, equally interesting tremolo effects are available also when a head-phone is used.  
  It is to be understood also that the loudspeaker or loudspeakers for the listener are fixed. Therefore, it is possible to use a loudspeaker or loudspeakers of large weight and large output. Thus, this system can be used also effectively in a large hall so that the present invention provides a very great advantage.  
  It should be understood further that, in the present invention it is possible to use. concurrently fo obtaining tremolo effects, an amplifier of a large output and a loudspeaker of a large input and a large output. both for non-tremolo purposes. Therefore, the present invention can be utilized with markedly great advantage as compared with the prior art with respect to the space occupied by the system and also to the cost. Moreover. the present invention is of the arrangement that the sounds having the tremolo effects are converted first to sound waves and then these tremolo sounds are picked up by microphones to reproduce tremolo effects. Therefore, there are obtained sound waves which are natural when heard and which are free of the so-called feeling of electrified sound. Thus, it is possible to enjoy an interesting performance of, for example, an electronic musical instrument.  
 I claim:  
  I. A tremolo effect producing system comprising, in combination, a tremolo effect producing unit having a closed housing, an electro-acoustic transducer capable of radiating sounds and supported rotatably in said housing, a plural number of acousto-electric transducers disposed at different positions within said housing to face said rotatable electro-acoustic transducer for picking up the sounds delivered from said electroacoustic transducer during its rotation and converting these sounds to electric signals, and means provided in said housing for giving rotation to said rotatable electro-acoustic transducer; amplifying means provided outside said housing for amplifying the electric signals from said plural number of acousto-electric transducers; and at least one electro-acoustic transducer provided outside said housing and connected to the output said of said amplifying means for converting the resulting amplified output signals to sound waves.  
  2. A tremolo effect producing system comprising, in combination, a tremolo effect producing unit having a closed housing, one electro-acoustic transducer capable of radiating sounds and supported rotatably in said housing, a plural number of acousto-electric transducers disposed at different positions within said housing to face said one rotatable electro-acoustic transducer for picking up the sounds delivered from said electroacoustic transducer during its rotation and converting these sounds to electric signals, and means provided in said, housing for giving rotation to said one rotatable electro-acoustic transducer; means provided outside said housing and connected to the output side of said tremolo effect producing unit for controlling the output signals of said acousto-electric transducers; at least one amplifier provided outside said housing and connected serially to said controlling means for amplifying the output signals after controlled by said controlling means; and at least one electro-acoustic transducer provided outside said housing and connected to the output side of said at least one amplifier for converting the resulting amplified output signals to sound waves.  
  3. A tremolo effect producing system comprising, in combination, a tremolo effect producing unit having a closed housing, one electro-acoustic transducer capable of radiating sounds and supported rotatably in said housing, a plural number of acousto-electric transducers disposed at different positions within said housing to face said one rotatable electro-acoustic transducer for picking up the sounds delivered from said one electro-acoustic transducer during its rotation and converting these sounds to electric signals, and means provided in said housing for giving rotation to said one rotatable electro-acoustic transducer; means provided outside said housing and connected to the output side of said a plural number of acousto-electric transducers, respectively, for controlling the output signals of these acousto-electric transducers, respectively; one amplifier provided outside said housing and connected serially to a joint of said controlling means for amplifying the resulting controlled output signals; and one electroacoustic transducer provided outside said housing and connected to the output side of said second-occurring one amplifier for converting the resulting amplified output signals to sound waves.  
  4. A tremolo effect producing system comprising, in combination, a tremolo effect producing unit having a closed housing, one electro-acoustic transducer capable of radiating sounds and supported rotatably in said housing, a plural number of acousto-electric transducers disposed at different positions within said housing to face said one rotatable electro-acoustic transducer for picking up the sounds delivered from said one electro-acoustic transducer during its rotation and converting these sounds to electric signals, and means provided in said housing for giving rotation to said one rotatable electro-acoustic transducer; means provided outside said housing and connected to the output side of said a plural number of acousto-electric transducers, respectively, for controlling the output signals of these acousto-electric transducers, respectively; amplifiers provided outside said housing and connected serially to said controlling means, respectively, for amplifying the resulting controlled output signals; and electroacoustic transducers provided outside said housing and connected to the output side of said last-occurring amplifiers, respectively, for converting the resulting amplified output signals to sound waves.  
  5. The system according to claim 1, in which said electro-acoustic transducers and said acousto-electric transducer are loudspeakers and a microphone, respectively.  
  6. The system according to claim 2, in which said electro-acoustic transducers and said acousto-electric transducers are loudspeakers and microphones. respectively.  
  7. The system according to claim 3, in which said electro-acoustic transducers and said acousto-electric transducers are loudspeakers and microphones, respectively.  
  8. The system according to claim 4, in which said electro-acoustic transducers are said acousto-electric transducers are loudspeakers and microphones, respectively.  
  9. A tremolo effect producing unit comprising a closed housing, an electro-acoustic transducer capable of radiating sounds and supported rotatably in said housing, a plural number of acousto-electric transducers disposed at different positions within said housing to face said electro-acoustic transducer for picking up the sounds delivered from said electro-acoustic transducer during its rotation and converting these sounds to electric signals, and means for giving rotation to said rotatable electro-acoustic transducer.