JP2625801B2 - Electric musical instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electric musical instrument, more specifically, a filter means for extracting a predetermined discrete frequency band from mechanical vibrations from a mechanical sound source, and converts the extracted mechanical vibrations into electric signals. And a positive feedback of the output electric signal from the amplifier, to which the electric signal from the converter is input, to the mechanical sound source. Is obtained.

(Prior Art) As a conventional electric musical instrument, for example, those shown in FIGS. 7 and 8 are known.

This shows an electric guitar, and this electric guitar
It has six strings 11 that are stretched between the tail piece 1 and the tip (head) 7 of the fingerboard 5 provided with the fret 3 and that pass over the bridge 9. The bridge 9 is connected to the electromechanical converter 13, the amplifiers 15, 17 and the loudspeaker 19.

Therefore, in this electric guitar, the vibration of the string 11 is converted into an electric signal by an electromagnetic pickup (mechanical converter) 13, and the output electric signal from the converter 13 is amplified by the amplifiers 15 and 17. The amplified electric signal output is converted by the loudspeaker 19 into a corresponding acoustic vibration. Further, the speaker output becomes an arbitrary level by adjusting the volume by the volume switch 21.

(Problems to be Solved by the Invention) However, in such a conventional electric musical instrument, even if an electric musical sound signal is accurately produced, the limit of the voltage vibration conversion capability of a speaker as a transducer is limited. It was inevitable. In other words, it is well known that the performance (fidelity) of a transducer (speaker) is extremely low in the audio field,
Electric musical instruments are also subject to the same restrictions as they emit sound signals from speakers as acoustic vibrations. As a result, there was a problem that an electric smell and unnatural sound were generated.

Therefore, an object of the present invention is to obtain an electric sound source that is close to the acoustic characteristics of a natural musical instrument.

(Means for Solving the Problems) The present invention provides a mechanical sound source, a converter for converting mechanical vibration of the mechanical sound source into an electric signal, and amplifying an output electric signal from the converter. In an electric musical instrument having an amplifier, a filter means, which is a resonator made of air for extracting mechanical vibration in a predetermined discrete frequency band among mechanical vibrations from the mechanical sound source, is converted into a mechanical sound source. An electric signal which is supplied between the filter and the filter and supplies the mechanical vibration selected by passing through the filter means to the converter, and the output signal from the amplifier is positively fed back to the mechanical sound source. Musical instrument. Further, instead of the above filter means, a filter means constituted by a resonator made of a film may be provided. This filter means may be constituted by a resonator composed of a block instead of these.

(Operation) In the electric musical instrument according to the present invention, a mechanical sound source such as a string, a head of a drum, a diaphragm of a loudspeaker or the like generates mechanical vibration. The converter converts this mechanical vibration into an electric signal and outputs it to an amplifier. The amplifier amplifies the output electric signal from the converter and feeds the output electric signal back to the mechanical sound source. That is, the mechanical sound source is mechanically vibrated by the electric signal whose phase is controlled by the amplifier and amplified.

The filter means extracts a predetermined discrete frequency band from the mechanical vibrations from the mechanical sound source, for example, a formant frequency of a specific sound of a specific musical instrument, or a certain range of frequency bands related to this formant frequency. . In this case, it is desirable to include frequencies around 500 to 2,000 Hz which are important for psychoacoustics, and discrete frequencies from the fundamental tone (27.5 Hz to 4,186 Hz for a piano) to the fifth harmonic. And the mechanical vibration which passed this filter means is supplied to the said converter.

As a result, only the vibration in the specific discrete frequency band that has passed through the filter means is supplied to the converter, converted into an electric signal, and amplified. That is, if an electrical or mechanical signal is applied to this system as a trigger, a sound having a specific frequency and emphasized characteristics can be obtained. The spectral energy distribution of the sound obtained here has a highly periodic envelope pattern, the formants are clear, the sound is good (particularly discrimination related to pitch), and the sound feels natural. .

(Example) Hereinafter, an example of an electric musical instrument according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic block diagram showing the entire configuration of an electric musical instrument according to a first embodiment of the present invention.

In FIG. 1, 31 is a key switch, and 33 is an amplifier. Reference numeral 35 denotes an acoustic filter. The acoustic filter 35 has a resonance tube of a predetermined length in which a speaker 37 and a microphone 39 are provided at both ends. The output of the amplifier 33 is input to the speaker 37, and the output of the microphone 39 is input to the amplifier 33 to form a feedback loop.

Reference numeral 41 denotes a speaker, and an amplifier 43 is interposed between the speaker 41 and the amplifier 33. That is, the output of the amplifier 33 is input to the speaker 41 via the amplifier 43 on the other hand.

In FIG. 1, a speaker 37 constituting an acoustic filter 35 is shown.
Functions as a mechanical sound source, and the microphone 39 is a mechanical-electrical converter that converts mechanical vibration into an electric signal.

FIG. 2 is a sectional view showing an application example of the acoustic filter 35.

In FIG. 2, reference numeral 51 denotes a resonance tube, and the resonance tube 51 is constituted by a cylindrical tube having a constant cross section. This resonance tube
The speaker 37 is provided at one end of the microphone 51, and the microphone 39 is provided at the other end thereof via a bracket 53 so that the position of the microphone 39 can be adjusted. The length of the resonance tube 51 is set to such a length as to cause air column resonance with respect to a sound of a predetermined frequency. That is, the pitch as a sound source is determined by setting the resonance frequency to a predetermined value.

Therefore, the air in the resonance tube 51 interposed between the mechanical sound source (speaker) 37 and the transducer (microphone) 39 constitutes a resonator as a propagation medium of sound waves (vibration), and the resonance tube Together with 51, a filter means (acoustic filter) 35 is constituted. The filter means 35 extracts only mechanical vibration in a specific frequency band such as a formant frequency.

In the electric musical instrument according to the above configuration, when the switch 37 is turned on and the speaker 37, which is the sound source, emits sound having a predetermined frequency characteristic, sound waves of a specific frequency are generated by the microphone 39 due to air column resonance in the resonance tube 51. Is extracted. And
In the microphone 39, the vibration is converted into a corresponding electric signal, and an appropriate control means, for example, a means for adjusting the phase, the gain, and the filter characteristic is used as necessary.
Is output to The amplifier 33 amplifies the output electric signal and supplies the amplified electric signal to the speaker 37 again. It constitutes a positive feedback circuit. As a result, the output of the speaker 37 is amplified in the specific frequency band, propagates through the resonance tube 51 again, and is detected by the microphone 39. At this time, air column resonance occurs in the resonance tube 51 in the same manner as described above. Therefore, in the specific frequency band, the vibration is amplified.

In other words, a discrete and highly periodic sound having a high output sound pressure in a specific frequency band in frequency characteristics can be obtained. The sound can be made closer to a natural sound.

In this device, a speaker is connected via an amplifier 43.
It is configured so that it can be pronounced externally by 41.

Further, if a baffle plate (partition plate with a through hole) is attached near the speaker 37 in the resonance tube 51, the length of the resonance air column becomes clear, and the characteristics are further enhanced.

FIG. 3 shows an acoustic filter according to a second embodiment of the present invention.

In this embodiment, a Helmholtz resonator 60 is used as an acoustic filter (filter means). That is,
A speaker 63 was provided as a mechanical sound source into the resonance chamber 61 having a predetermined spherical volume, and a microphone 65 as a converter for converting the mechanical vibration into a voltage was attached to the resonance chamber 61. Things. Further, the resonance chamber 61 has an opening 67 having a predetermined sectional area. The microphone 65 may be attached to the outside of the resonance chamber 61 and in the vicinity of the opening 67 as in the first embodiment. Other configurations are the same as those of the above embodiment.

Therefore, as in the above-described embodiment, the Helmholtz resonator 60 in which air serves as a resonance medium amplifies the vibration in a specific frequency band by a positive feedback loop as the filter means. Also, the resonance frequency can be changed by closing the opening 67 half by hand. Other operations are the same as those in the above embodiment.

 FIG. 4 shows a third embodiment of the present invention.

In this embodiment, the present invention is applied to a drum which is a film sounding instrument.

That is, the electromagnetic actuator 81 is used as a mechanical sound source.
Are arranged inside the body 83, and a conductor pattern is provided on the back surface of the head 85 so that the head 85 can be vibrated by suction repulsion. In addition, the head 85 is configured by using an electromagnetic pickup as a converter, for example, by combining pattern deposition and an electromagnetic coil. Therefore, the head 85, which is a film body, transmits film vibration in a specific frequency band to the pickup according to the tension. The head 85 and the actuator 81 constitute a filter means and a mechanical sound source, respectively.

The tension is adjustable by tension adjusting means 87.

Other configurations and operations are the same as those of the above embodiments.

FIG. 5 and FIG. 6 show a fourth embodiment of the present invention.

In this embodiment, the present invention is applied to a body musical instrument.

Vibration is applied to a dora (block) 93 supported by a stand 91 by an actuator 95 of an electromagnetic type, a piezoelectric type, or the like, and only vibration in a frequency band specified by the material and size of the disk of the dora 93 is applied. It is extracted by the pickup 97.

Therefore, in this embodiment, the disk (drum) 93 as a resonator constitutes the filter means.

Other configurations and operations are the same as those of the above-described embodiments.

(Effects) As described above, according to the present invention, a sound similar to that of a natural musical instrument can be obtained without the electric odor as the sound emitted by the electric musical instrument. A sound having a high output sound pressure in a specific frequency band can be obtained.

The number of sound sources can be determined according to the number of required pitches.

[Brief description of the drawings]

FIG. 1 is an overall circuit diagram showing a first embodiment of an electric musical instrument according to the present invention, FIG. 2 is a sectional view showing an acoustic filter according to the first embodiment, and FIG. 3 is a second embodiment. FIG. 4 is a sectional view showing an acoustic filter according to a third embodiment, FIG. 5 is a side view showing an acoustic filter according to a fourth embodiment, FIG. FIG. 7 is a front view showing an acoustic filter according to an embodiment, FIG. 7 is a perspective view showing a schematic overall configuration of a conventional electric guitar, and FIG. 8 is a block diagram showing an overall configuration of the conventional electric guitar. 33… Amplifier, 35… Acoustic filter, 37…
Speaker (mechanical sound source), 39 ... Microphone (converter).

Claims (3)

(57) [Claims] An electric musical instrument comprising: a mechanical sound source; a converter for converting mechanical vibration of the mechanical sound source into an electric signal; and an amplifier for amplifying an electric signal output from the converter. A filter means, which is a resonator made of air for extracting mechanical vibration in a predetermined discrete frequency band among the mechanical vibrations from the mechanical sound source, is provided between the mechanical sound source and the converter; An electric musical instrument characterized in that a mechanical vibration selected by passing through the means is supplied to the converter, and an output signal from the amplifier is positively fed back to a mechanical sound source. 2. An electric musical instrument comprising: a mechanical sound source; a converter for converting mechanical vibration of the mechanical sound source into an electric signal; and an amplifier for amplifying an electric signal output from the converter. Filter means, which is a resonator made of a film for extracting mechanical vibration in a predetermined discrete frequency band among mechanical vibrations from the mechanical sound source, is provided between the mechanical sound source and the converter. An electric musical instrument characterized in that a mechanical vibration selected by passing through the means is supplied to the converter, and an output signal from the amplifier is positively fed back to the mechanical sound source. 3. An electric musical instrument comprising a mechanical sound source, a converter for converting mechanical vibration of the mechanical sound source into an electric signal, and an amplifier for amplifying an electric signal output from the converter. Filter means, which is a resonator comprising a block for extracting mechanical vibration in a predetermined discrete frequency band among mechanical vibrations from the mechanical sound source, is provided between the mechanical sound source and the converter; An electric musical instrument characterized in that a mechanical vibration selected by passing through the means is supplied to the converter, and an output signal from the amplifier is positively fed back to the mechanical sound source.