Orally Operated Electronic Musical Instrument

Abstract

Means forming an air channel is connected between the output of a loudspeaker and the input of a microphone. The output of the microphone is amplified by means of an amplifier, the output of the amplifier being fed to the speaker, an acoustical feedback path thus being formed between the speaker and the microphone. A mouthpiece is connected in this acoustical path such that an operator can determine the frequency of the feedback signal by adjusting the size of his oral cavity, thus forming musical tones.

Description

This invention relates to electronic musical instruments, and more particularly to such an instrument in which the basic tones are determined by the operator's oral cavity.

In whistling and singing, the size of the oral cavity is varied so as to resonate at various frequencies to produce a range of tones. Various musical instruments have been devised in the prior art for making use of this capability. Such devices, however, generally involve the introduction of an externally generated sound which is filtered or modulated by the oral cavity.

The device of this invention is a unique improvement over such prior art devices in that the frequencies of the basic tones are determined by means of the oral cavity itself, with no external source of sound being involved. This provides a unique acoustical effect not present in prior art devices in that the operator himself can determine the basic generated tone, The device of the invention further can be fabricated from a minimum number of components which can be assembled at a relatively low cost.

It is therefore an object of this invention to provide a unique electronic musical instrument.

It is a further object of this invention to enable the formation of musical tones by means of one's oral cavity without the use of the vocal cords or an external sound source.

It is another object of this invention to provide a unique electronic musical instrument which utilizes the intuitive capacities of the operator in forming tones.

Other objects of the invention will become apparent as the description proceeds in connection with the accompanying drawings, of which:

FIG. 1 is a perspective view illustrating one embodiment of the device of the invention;

FIG. 2 is a view of the embodiment of FIG. 1 partially cross-sectioned to illustrate the various components thereof;

FIG. 3 is a schematic drawing of the electrical and acoustical circuitry of the embodiment of FIG. 1;

FIG. 4 is a view in partial cross-section of a second embodiment of the device of the invention; and

FIG. 5 is a schematic drawing illustrating the electrical and acoustical circuitry of the embodiment of FIG. 4.

Briefly described, the device of the invention is as follows: The cone of a loudspeaker is used to form one wall of an enclosure. A channel forming an acoustical path connects this enclosure to another enclosure in which a microphone is contained. A mouthpiece is inserted in this channel. An amplifier is used to amplify the output of the microphone, the output of the amplifier being connected to the speaker. An acoustical feedback path is thus formed between the speaker and the microphone. When an operator places his lips on the mouthpIece, he can determine the frequency of the feedback signals by varying the effective size and thus the resonant frequency of his oral cavity. It is thus possible to generate musical tones. A pressure-responsive switch may be connected to the mouthpiece so that it is responsive to blowing pressure of the operator, this switch being placed either in the electrical or acoustical circuit so as to complete either of these circuits only when the operator is expelling air.

In one embodiment of the invention the tone output comes directly from the cone of the speaker utilized in the feedback circuit. In a second embodiment of the invention both sides of the speaker cone are enclosed by containing walls and the output tones are generated by taking the output of the amplifier in the feedback circuit and feeding this to another amplifier which drives a separate loudspeaker. This second embodiment has the advantage of permitting control of the amplitude and other qualities and characteristics of the tones.

Referring now to FIGS. 1 and 2, one embodiment of the device of the invention is illustrated. Casing 11 houses amplifier circuitry and power source therefor which may comprise batteries or an AC power supply for furnishing DC. Mounted on casing 11 is speaker housing 13. Speaker housing 13 includes a horn portion 13a for acoustically aiding the transmission of the sound radiated by the rear surfaces of the speaker cone 15a of speaker 15. Housing 13 further includes a speaker enclosure portion 13b which, with the front surface 15b of the speaker cone, forms an enclosure for the sound radiated by the front of the speaker. The rim portion 15c of the speaker is sealed to a ridge 13c which runs along the inner wall of the housing so that the speaker effectively forms a sealed wall of enclosure portion 13b. A pressure relief hole 13d is formed in enclosure portion 13b to permit a rapid reduction in pressure when the operator stops expelling air so the pressure actuated switch can open to end the note.

A microphone 17, which may be of the dynamic type, is mounted in casing 19. An air channel is provided between enclosure portion 13b and casing 19 by means of tube 21 which has fluid communications to the inside of enclosure portion 13b and tube 23 which provides fluid communications between tube 21 and casing 19. The input portion 17a of microphone 17 faces towards the input of tube 23. Thus, an acoustical channel is formed between the output of speaker 15 and the input of microphone 17. A mouthpiece 21a is formed at the end of tube 21 for use in operating the instrument. It is to be noted that tube 23 effectively provides a probe for transmitting sound energy to the microphone.

For optimum results, tube members 21 and 23 should be as short as possible so as to minimize phase lag in the acoustical path provided thereby which would tend to limit the high frequency range of the instrument. Further, microphone probe 23 should be connected to tube 21 as close to mouthpiece 21a as possible, to most accurately reflect the characteristics of the sound developed in the operator's oral cavity.

Pressure-actuated switch 25 is housed in casing member 27, an air channel being formed between casing 27 and enclosure portion 13b by means of tube member 29. The contacts of pressure actuated switch 25 are connected in series between microphone 17 and the amplifier contained in housing 11, as shown schematically in FIG. 3. Switch 25 may comprise any switch unit sensitive to air pressure, such as for example an elastic membrane 25a which closes contacts 25b and 25c in response to an air pressure signal.

In operating the device, an operator 30 places his lips over mouthpiece 21a and blows into the mouthpiece, at the same time forming a tone to be played with his oral cavity 30a. The oral cavity size is varied as in whistling or singing to form the tone. The simultaneous blowing action provides a pressure signal which closes switch 25, providing an electrical path from microphone 17 to amplifier 33 (see FIG. 3). The sound from the amplifier is fed to speaker 15 and an acoustical feedback path is provided from the speaker to the microphone through tube 21 and microphone probe 23, resulting in oscillation. The frequency and acoustical characteristics of this oscillation are determined by the acoustical resonance characteristics of the oral cavity 30a, the operator being able to change these characteristics to produce various tone outputs.

It is to be noted that the speaker cone must be substantially airtight so that air pressure can be built up on the front portions 15b thereof. Further the front portion of the speaker cone should be waterproofed because of the high level of condensation that occurs within enclosure portion 13b when the instrument is operated. It is further to be noted that electrical pressure actuated switch 25 could be replaced by a pressure actuated valve located in the acoustical feedback path, e.g., a flap valve located in tube 21 or microphone probe 23.

Referring now to FIG. 3, the first embodiment of the invention is schematically illustrated. The output of microphone 17 passes through pressure actuated switch 25 and thence is amplified by means Of voltage amplifier 33 and power amplifier 37, the output of amplifier 37 being fed to loudspeaker 15. Equalization is used in the amplifiers to compensate for phase shifts introduced into the system by virtue of the loudspeaker and microphone characteristics. For optimum response the feedback components of the microphone output should be in phase with the signal that produced it. The acoustical output of speaker 15 is connected by means of acoustical channel 35 to the input of microphone 17. Connected to the acoustical channel 35 is a resonant cavity 30a formed by the oral cavity of the operator. The frequency of the acoustical feedback and thus the frequency of the amplifier and speaker outputs is determined by the resonant frequency of oral cavity 30a which is determined by the operator of the instrument.

Referring now to FIGS. 4 and 5, a second embodiment of the device of the invention is illustrated. This second embodiment is similar to the first, except that the output of the speaker in the acoustical feedback circuit is not used as the sound output, the tone output rather being derived from a separate speaker which receives a signal from the power amplifier. As can be seen in FIG. 4, speaker 15, rather than having a horn to radiate the output of the back cone surfaces 15a, is fully enclosed in casing 13. Also, a separate speaker 42, which may be of a larger size than speaker 15, is utilized in conjunction with a separate amplifier to radiate the sound, as now to be explained in connection with FIG. 5. Otherwise, the second embodiment is the same as the first just described.

Referring now to FIG. 5, an acoustical feedback path 35 is provided as before between the output of speaker 15 and the input of microphone 17 with the oral cavity 30 a being used to form the tones. The output of microphone 17 is fed through pressure actuated switch 25 to voltage amplifier 35 and thence to power amplifier 37 the output of which is fed to speaker 15. Speaker 15 is fully enclosed in casing 13 so that except for the acoustical feedback, there is a minimum amount of radiation from the speaker cone. The output of amplifier 37 is also fed through potentiometer 41 to the input of amplifier 43, the output of amplifier 43 being fed to speaker 42. Potentiometer 41 is used as a volume control to control the sound output of the speaker 42. Other controls may also be incorporated in amplifier 43, such as tone controls, modulation controls, etc. Further, modulation signals can be introduced into the amplifier from external sources to further modify the musical sounds generated. Thus, the second embodiment affords greater versatility of operation and enables the utilization of a separate higher fidelity sound system in radiating the sound output. Further, potentiometer 41, amplifier 43 and speaker 42 may be formed by an existing sound system to which the output of amplifier 37 is fed.

The musical instrument of this invention thus provides a unique device for generating tones with one's oral cavity without the use of the vocal cords or an external tone signal.

While the device of this invention has been described and illustrated in detail, it is to be clearly understood that this is intended by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of this invention being limited only by the terms of the following claims.

Claims

I claim:

1. A mouth operated electronic musical instrument for use in forming tones comprising:

a microphone,

a loudspeaker,

amplifier means for amplifying the output of said microphone, the output of said amplifier means being fed to said loudspeaker,

means for providing an acoustical feedback path between the loudspeaker and the microphone input comprising a casing for enclosing said microphone, enclosure means for forming an enclosure with said loudspeaker, and tube means for interconnecting said casing and said enclosure means, and

a mouthpiece connected to said means for providing a feedback path.

2. The instrument of claim 1 wherein said tube means comprises a first tube connected at one end thereof to the enclosure means, said mouthpiece being located at the other end of said first tube, and a second tube interconnecting said first tube and said casing.

3. The instrument of claim 1 wherein said enclosure means for forming an enclosure with said loudspeaker comprises a housing having an open end portion forming a horn for said loudspeaker, said loudspeaker having a speaker cone and being mounted in said housing, one side of said cone forming an enclosure with said housing, the other side of said cone radiating sound through said horn, said tube means being connected to the last mentioned enclosure.

4. The instrument of claim 1 wherein said enclosure means comprises a casing enclosing said loudspeaker and further including an amplifier connected to receive the output of said amplifier means and a second loudspeaker connected to receive the output of said amplifier.

5. A mouth operated electronic musical instrument for use in forming tones with an operator's oral cavity comprising:

a microphone,

a casing for enclosing said microphone,

a loudspeaker having a cone for radiating sound,

a housing for said loudspeaker, the cone of said speaker and said housing forming an enclosure for the sound radiated by one side of said cone,

amplifier means for amplifying the output of said microphone, the output of said amplifier means being fed to said loudspeaker,

means providing an air channel interconnecting the microphone casing and said enclosure, and

a mouthpiece for use by the operator, connected to said last mentioned means.

6. The instrument of claim 5 and further including a switch having a pressure responsive actuator and a pair of electrical switch contacts, a casing member for housing said switch and means for providing an air channel between said casing member and said mouthpiece, said switch contacts being interposed between said microphone and said loudspeaker, whereby said switch contacts are closed only when there is a predetermined air pressure signal at said mouthpiece.

7. The instrument of claim 5 wherein said housing is shaped to form a horn for radiating sound from the other side of the loudspeaker cone.

8. The instrument of claim 5 wherein said housing encloses the other side of said cone and further including an amplifier connected to receive the output of said amplifier means and a second loudspeaker driven by the output of said amplifier to provide the sound output.

9. A mouth operated electronic musical instrument for use in forming tones comprising:

a microphone,

a loudspeaker,

amplifier means for amplifying the output of said microphone, the output of said amplifier means being fed to said loudspeaker,

means for providing an acoustical feedback path between the loudspeaker output and the microphone input,

a mouthpiece connected to said means for providing a feedback path,

pressure actuated switch means for controlling the generation of said tones, and

channel means interconnecting said switch means and said mouthpiece,

said switch means being actuated to cause tones to be generated only when a pressure signal is introduced into said mouthpiece.

10. The instrument of claim 9 wherein said pressure actuated switch means is an electrical switch interposed between said microphone and said loudspeaker.