JPS6134559Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electric piano that converts string vibrations into electrical signals using a pickup made of long piezoelectric elements and emits sound from a speaker.

A conventional electric piano of this type has a configuration as shown in FIG. 1 to make it look like a piano.
That is, between the frame a and the string receiving member b,
A pick-up c made of a long piezoelectric element and composed of a bass part c ₁ and a mid-treble part c ₂ is interposed, and each electrode conductor _d 1 of the bass part c ₁ and mid-treble part c ₂ of the pick-up c is interposed. , d ₂ are mixed via amplifiers e ₁ and e ₂ , and the combined signal is further amplified by amplifier g and sent to a low-pass filter h ₁ and a high-pass filter h _{2 .} The sound is then separated into high frequencies and low frequencies, and the sound is emitted from the bass range speaker i ₁ placed on the left side and the treble range speaker i ₂ placed on the right side when facing each other.

However, with this circuit, when you play a key in the bass range, the fundamental tone and its surrounding low-order harmonics (low frequencies) are emitted from the left bass range speaker i ₁ , and the high-order harmonics (high frequencies) are emitted from the right speaker. Since the sound is emitted from the high range speaker i ₂ , especially when playing chords, low frequencies are emitted from the left side and high frequencies from the right side, resulting in an unnatural sound that differs from that of a piano. .

The present invention eliminates the above-mentioned drawbacks of the conventional method, and allows low-range sounds, including high-order overtones, to be emitted from the left bass speaker, and high-range sounds to be emitted from the right speaker. The purpose is to make it possible to produce a sound with a sense of spaciousness, and the vibration of the string is converted into an electric signal by a pick-up consisting of a long piezoelectric element, and the sound is emitted from a speaker. The electrical signals generated by the vibration of the string are derived from a plurality of spaced apart points of the electrode conductor of the pickup having a predetermined resistance value, and the electrical signals are respectively input to an amplifier having a predetermined input resistance, and the output of the amplifier is The system is characterized in that the sound is emitted from speakers placed at spatially separated positions.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a wiring diagram of the first embodiment.
1 is a pick-up consisting of a long piezoelectric element, which is formed by one continuous piece from low to high pitch.
The piezoelectric element has, for example, a center conducting wire electrode,
An elastic piezoelectric material made of rubber, synthetic resin, etc. mixed with piezoelectric ceramic powder, molded, vulcanized, or crosslinked, and polarized is placed around it, and an elastic piezoelectric material with a cylindrical electrode and an insulating protective coating on the outside. A body element is used.

In this embodiment, the center conducting wire electrode 1' is made of a material having a higher resistance value than conventional conducting wires, such as a nickel-chromium alloy, resin mixed with carbon powder, conductive rubber, carbon fiber, or other material made of carbon fiber. A combination of fibers (for example glass fibers) is used, and both ends of the electrode 1' are connected to first stage amplifiers 2, 2' each having an input resistance Ri. The signals amplified by the first-stage amplifiers 2, 2' are applied via main amplifiers 3, 3' to speakers 4, 4' for bass and treble ranges, which are spaced apart on the left and right.
A sound is emitted.

Now, when the string 5 at point a of the pickup 1 vibrates, a voltage ea is generated at the center conductor electrode 1' at that point, and the current due to this voltage passes through the center conductor electrode 1' to the first stage amplifiers 2, 2'. Flows into input resistor Ri. a
The resistance value determined by the length of the center conducting wire electrode 1' from the point to the end point b on the bass side is r ₁ , and the resistance value determined by the length from the point a to the end point c on the treble side side is r 1 r ₂ , the input voltage e ₂ of the first stage amplifier 2 on the bass side is ea・Ri/r ₁ + Ri [V], and the input voltage e ₂ ′ of the first stage amplifier 2' on the high frequency side is ea・Ri/r ₂ +Ri [V]
becomes.

Therefore, when point a approaches the bass side, the resistance value
Since r ₁ <r ₂ and the input voltage of the first stage amplifier e ₂ >e ₂ ', the low frequency range speaker 4 emits sound at a higher level than the high frequency range speaker 4'. On the contrary, when point a approaches the treble end, the input voltage e ₂ <e ₂ ', and the sound is heard louder from the right side, that is, from the treble speaker 4'.

Therefore, when the left key is played, the low-frequency fundamental tone, the low-order harmonics around it, and the high-frequency harmonics are emitted from the left speaker 4, and when the right key is played, the right sound is emitted. The sound is emitted from the speaker 4', and you can hear a musical tone similar to that of a piano.

Also, when playing chords, each pitch can be heard separately, creating a spaciousness similar to that of a piano.

When a key in the middle range is played, the input voltage e ₂ ≈e ₂ ' of the first stage amplifiers 2, 2' becomes, and the sound can be heard near the middle between the left and right speakers 4, 4'.

FIG. 3 shows another embodiment of the present invention, in which the output of the pickup 1 is not connected to both ends of the central conductor electrode 1',
Each of these is derived slightly from within.
In this way, it is possible to prevent a drop in the output of the pickup 1 in the middle range and an excessive output in the lowest and highest ranges, and it is possible to uniformly derive the output level from the low range to the high range.

Figure 4 shows an attempt to further improve the output level in the midrange than in Figure 3, and Figure 4A shows an additional speaker 4'' for the midrange in the center, with a conductor electrode in the center. 1' is amplified by the first-stage amplifier 2'' and the main amplifier 3'', and the sound is emitted. In Figure 4B, the speaker 4'' for the midrange is not added. First, the pick-up output derived from approximately the center of the center conducting wire electrode 1' is coupled to an amplifier circuit for high and low ranges via a mixing circuit, and the sound is emitted from speakers 4 and 4' for low and high ranges. This is how it was done.

Although a cable-shaped elastic piezoelectric element has been described as an example of the elongated piezoelectric element, the present invention is not limited to this, and various other types can be used. In this way, according to the present invention, the electric signals generated by the vibration of the string are derived from a plurality of spaced apart points of the electrode conductor having a predetermined resistance value of a long pickup, and the electric signals are inputted through a predetermined input resistance. Since the outputs of the amplifiers are emitted from speakers placed at spatially separated positions, it is possible to produce a sound with a sense of spaciousness similar to that of a piano. .

[Brief explanation of the drawing]

Figure 1 is the electrical circuit diagram of a conventional electric piano, Figure 2
3 and 4A and 4B respectively show electrical circuit diagrams of embodiments of the present invention. 1...Pickup, 1'...Electrode conductor, 2,
2', 3, 3'...amplifier, 4,4'...speaker, 5...string.

Claims (1)

[Scope of utility model registration request] In a type of pickup that uses a long piezoelectric element to convert the vibration of a string into an electric signal and emit sound from a speaker, the vibration of the string is transmitted from a plurality of spaced apart points of the electrode conductor of the pickup having a predetermined resistance value. It is characterized by deriving the generated electrical signals, inputting the electrical signals to amplifiers each having a predetermined input resistance, and emitting the output of the amplifier from speakers placed at spatially separated positions. An electric piano.