JPS6140116B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a volume control device for an electronic musical instrument, and more particularly to a volume control device capable of producing an expression (intonation due to volume change) effect that feels natural to the ear.

In conventional electronic musical instruments, especially electronic musical instruments such as electronic organs and music synthesizers that have a sustain function (the sound of the performance gradually decays after the key is released), a sound source signal with a pitch corresponding to the key press is set. The resulting volume envelope modulates the amplitude, and an expression circuit controlled by an expression pedal further modulates the amplitude to produce a well-defined performance sound. However, since double independent amplitude modulation is performed in this way,
Each musical tone that comes out as a result of a key press has an audibly unnatural change in volume. In other words, even though the musical tone signal before passing through the expression circuit has an optimally set natural volume envelope, as shown in A of FIG.
The musical tone signal after being amplitude modulated by the expression circuit has a very unnatural volume envelope that rises in the middle of the attenuation process, as shown in Figure 5B. As a result, the change in volume of the performance sound inevitably becomes extremely unnatural.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional art.
To provide a volume control device for an electronic musical instrument that can obtain an audibly natural performance sound by making it dependent on the value of the amount of pedal depression at the time of key release.

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

FIG. 1 shows an embodiment of the present invention. 1 is a volume control device for setting and operating the volume of the performance sound;
Specifically, it is composed of an expression pedal 101. 2 is a volume level signal generator;
A volume level voltage d having a value corresponding to the amount of depression of the expression pedal 101 is output. Reference numeral 5 denotes a keyboard consisting of a plurality of keys provided corresponding to pitches. 7-1, 7-2, 7-3, and 7-4 are musical tone signal generation channels, which use given pitch data and key press signals to push musical tone signals with pitches based on the pitch data. Outputs in synchronization with the key signal. In the embodiment shown in FIG. 1, the pitch data has pitch voltages V ₁ , V ₂ , V ₃ , and V ₄ that are proportional to the pitch. Reference numeral 6 denotes a generator assigner, which has the same function as the already known generator assigner, such as ``Multiplex device for selecting pitch and voice in electronic musical instruments'' published in Japanese Patent Publication No. 50-33407. 5 is detected, musical tone signal generation channels 7-1, 7-2, 7-3, and 7-4 are assigned to each of the pressed keys, and the keys assigned to each channel are It supplies key press signals a ₁ to a ₄ indicating the pressed/released state and pitch data corresponding to the keys. As described above, in the embodiment, pitch data is supplied as pitch voltages V ₁ to V ₄ to musical tone signal generation channels 7-1 to 7-4, respectively. The musical tone signal generation channel 7 is triggered by a VCO (voltage controlled oscillator) 9 serving as a tone source oscillator, a VCF (voltage controlled filter) 10 serving as a tone filter, and the leading edge (rising edge) of the key press signal a.
It consists of an envelope signal generator 11 that generates an envelope voltage signal to control the VCF 10. 3-1, 3-2, 3-3, and 3-4 are musical tone signal generation channels 7-1, 7-2, and 7-, respectively.
3, 7-4, and a generator/
Key press signals a ₁ , a ₂ , a ₃ , sent from the assigner 6
When each of a ₄ indicates a key press (high level voltage), the volume level voltage d, which is the output of the volume level signal generator 2, is buffered and output (i.e. tracking operation) to indicate a key release. (low level voltage), a track that stores and outputs the volume level voltage d at the time when the key pressed state changes to the key released state (changes from high level voltage to low level voltage).・
This is a hold circuit, and specifically, it is constituted by an analog track and hold circuit known to track and hold an analog voltage as shown in 3 in FIG.

4-1, 4-2, 4-3, and 4-4 are musical tone signal generation channels 7-1, 7-2, 7-3, and 7, respectively.
The output envelope voltage signal of the envelope signal generator 3-4 is converted into the output voltage _b1 ,
Amplify with a gain corresponding to b ₂ , b ₃ , b ₄ and convert the voltage signal
It is a variable gain amplifier that outputs C ₁ , C _{2 ,} C ₃ , and C ₄ respectively. Specifically, as shown in 4 in Figure 3, it is realized by a VCA (voltage control amplifier) that uses output voltage b as the control voltage. Ru. 8-1 to 8-4 output the musical tone signals of the musical tone signal generation channels 7-1 to 7-4, respectively, with gains corresponding to the output voltage signals _C1 to _C4 of the variable gain amplifiers 4-1 to 4-4, respectively. It is a gate amplifier that outputs musical tone signals e ₁ to _{e 4} that have been amplified and have a volume envelope added (amplitude modulation), respectively. Specifically, it is a VCA that uses a voltage signal Cn (n = 1 to 4) as a control voltage. (voltage controlled amplifier). A mixing circuit 12 mixes the output signals e ₁ to e ₄ of the gate amplifiers 8-1 to 8-4.
The output signal f of the mixing circuit 12 is converted into a musical tone through an amplifier and a speaker.

Next, the operation of the embodiment shown in FIG. 1 will be explained. FIG. 2 shows the output waveforms of each part in FIG. 1. Second
a ₁ to f in the figure are a ₁ to f added to Fig. 1.
These are the output waveforms corresponding to the respective outputs. The player is now operating the keyboard 5 and expression pedal 101, and the note names C ₃ , E ₃ , G ₃ , C ₄ ,
As the keys E ₄ , G ₄ , and F ₄ were pressed in sequence, the volume level signal generator outputted a volume level voltage d as shown in FIG. 2d in response to the amount of depression of the expression pedal 101. shall be taken as a thing. To simplify the explanation, the number of musical tone signal generation channels 7 is assumed to be 4.
Although the explanation is limited to these four musical tone signal generation channels 7, the generator assigner 6 is newly pressed for an empty one (not assigned to any pressed key). It has a function to allocate keys. Once the allocation is decided,
The generator assigner 6 generates pitch voltages V ₁ to V ₄ corresponding to the pitches of the keys respectively assigned to the four musical tone signal generation channels 7-1 to 7-4,
Key depression signals a ₁ to a ₄ indicating the key depression state of each assigned key are supplied, respectively. Figure 2 shows the response output waveforms of each part associated with the pressing and releasing operations of the seven keys corresponding to the note names C ₃ to F ₄ mentioned above.
Since each of the musical tone signal generation channels 7-1 to 7-4 operates in the same way, one of them, the musical tone signal generation channel 7-1 (hereinafter referred to as
I will focus only on CH ₁ ) and explain it. At time t ₁ in FIG. 2, in response to the key press of tone C ₃ , the generator assigner 6 allocates CH ₁ and supplies the pitch voltage V ₁ of tone name C ₃ to the control input of VCO 9 of CH ₁ . In addition, the low level when the key is released,
When a key is pressed, a key press signal _a1, which is a high-level voltage signal, is supplied to the trigger input of the CH ₁ envelope signal generator 11 and the gate input of the track hold circuit 3-1. The rise of this key press signal _a1 turns on the analog switch S _G (Fig. 3), and the track/hold circuit 3-1 tracks the volume level voltage d output from the volume level signal generator. A tracking voltage b ₁ is outputted from time t ₁ to _{t 2} in FIG. 2 b ₁ . Variable gain amplifier 4-
1 serves as an amplifier whose gain changes in accordance with this tracking voltage _b1 , and waits for the output envelope voltage signal of the envelope signal generator 11. On the other hand, the VCO 9 of CH ₁ outputs a sound source signal having a sound source frequency corresponding to the pitch name C ₃ using the pitch voltage V ₁ of the given tone C ₃ . This sound source signal is given timbre by the subsequent VCF 10 and sent out from CH ₁ . In addition, the envelope signal generator 11 of CH ₁
is triggered by the rising edge of the key press signal _a1 at time _t1 , and generates an envelope voltage that changes with time. This envelope voltage VCF10 is supplied to the control input, and becomes a modulation signal that modulates the spectrum of the musical tone signal of _CH1 . Now, the output envelope voltage signal of the envelope signal generator 11 is amplified (or attenuated) by a variable gain amplifier _4-1 whose gain is controlled by the tracking voltage b1 from time _t1 to _t2 , and then from time t1 _{to t2} in FIG. The output voltage signal C ₁ has a waveform such as C ₁ at t ₂ . The gate amplifier 8-1 amplifies, or gates, the output musical tone signal of CH ₁ with a gain proportional to this output voltage signal C ₁ and outputs a signal e ₁ . The mixing circuit 12 mixes the output musical tone signals e ₁ to e 4 of the four gate amplifiers 8-1 to _8-4 with equal weight and outputs a signal f. Therefore, from time _t1 to _t2 , the musical tone signal f of note name _C3 gated by the amplified envelope voltage signal _C1 appears at the output of the mixing circuit 12, as shown at f in FIG.

The key with pitch name _C3 that was pressed at time _t1 is released at time _t2 , and the key press signal _a1 changes from high level to low level. In synchronization with this, the output voltage of the envelope signal generator 11 of CH ₁ gradually attenuates. Along with this, the amplitude of the output musical tone signal _e1 of the gate amplifier 8-1 also gradually attenuates and disappears.
By releasing the key at time _t2 , the analog switch S _G
is turned off, the track/hold circuit 3-1 shifts to the hold state, and as shown in _b1 from time _t2 to _t3 in FIG. 2, the volume level voltage V stored at _t2 when the key is released is (t ₂ ) continues to be stored in memory. That is, the gains of the variable gain amplifiers 4-1 to 4-4 are maintained at a constant value from the time the key is released until the next key depression.
Now, the key with the pitch name _E4 is pressed, _CH1 is assigned again, and the key press signal _a1 rises at time _t3 , but the subsequent operation is exactly the same as described above. When the key is released at time _t4 , the track hold circuit 3-1 memorizes and maintains the volume level voltage V( _t4 ) at the time of key release, as in the previous case, and as a result, from the gate amplifier 8-1 are the note names C ₃ and E ₄ in Figure 2 f.
A musical sound waveform f with a natural attenuation envelope such as
Output.

Now, the same operation is performed for the other three musical tone signal generation channels 7-2 to 7-4 (referred to as CH ₂ to CH ₄ , respectively), and the respective channels are as shown in f in Fig. 2. A musical tone signal f having a natural attenuation envelope is obtained, and the output musical tone signal f of the mixing circuit 12 is converted into a musical tone by a subsequent amplifier and speaker.

Now, the musical tone signal f obtained by comparing d and f in FIG.
It can be seen that the intonation changes corresponding to the amount of operation, and each note has a natural attenuation envelope as set.

In addition, voltage output type volume level signal generator 2
This can be easily realized using a known circuit (not shown) that exchanges a change in the resistance of a variable resistor, which is varied by operating the expression pedal 101, with a change in voltage, for example.

In the above embodiment, the output d of the volume level signal generator 2 is an analog DC voltage signal, and the track and hold circuit 3 and the variable gain amplifier 4 are respectively an analog track and hold circuit and a VCA. The volume level voltage d need not be an analog DC voltage, but may be a digital signal represented by a binary logic level. In that case, the volume level signal generator 2 can be easily realized with a known circuit (not shown) using, for example, a digital rotary encoder rotated by the operation of the expression pedal 101.
At this time, if the output volume level voltage d is 4 bits, the track and hold circuit 3 can be realized by a known transparent latch circuit such as TTL SN74373 manufactured by TI as shown in FIG. This transparent latch circuit has 4
When the key press signal a is at a high level, the bit volume level voltage d is simply buffered and output, and when the key press signal a goes to a low level, it is latched and output at the falling edge.

Further, the variable gain amplifier 4 can be realized by a known digital programmable amplifier as shown in FIG. This digital programmable amplifier amplifies the output envelope voltage signal of the corresponding envelope signal generator with a gain proportional to the digital value of the output digital signal of the transparent latch circuit. This allows the gain (expression level) to be set, albeit discretely. If a finer gain step is required, it can be achieved by increasing the number of bits of the volume level voltage d.

Further, in the embodiment, the number of tone signal generation channels 7 is four, but of course there is no limit to this number, and it is clear that the same implementation can be achieved even if there is only one (for a monophonic instrument).

In actual design, care should be taken so that the variable gain amplifier 4 has finished setting the new gain before the musical tone signal corresponding to the newly pressed key is generated from the musical tone signal generation channel 7. It is. This is because if the gain of the variable gain amplifier 4 changes after the start of sound generation, undesirable problems such as clipping may occur. Therefore, there is no problem if, for example, a delay circuit is provided before the trigger input of the envelope signal generator 11 to delay the generation of the envelope voltage signal a little.

As explained above, according to the present invention, the performance sound has an intonation that corresponds to the operation amount of the volume control device such as the expression, and each note has a set natural attenuation volume envelope. The effect is extremely high, since it is possible to create an electronic musical instrument that can

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram of an embodiment of the present invention;
The figure shows the output signal waveform diagram of each part of the embodiment shown in Fig. 1.
The figure is a circuit configuration diagram showing a specific embodiment of the track and hold circuit 3 and variable gain amplifier 4 in the embodiment of FIG. 1, and FIG. FIG. 5, a circuit diagram showing another specific embodiment of the amplifier 4, is a diagram for explaining the drawbacks of the conventional amplifier. 1... Volume operation diagram, 2... Volume level signal generator, 3... Track/hold circuit, 4... Variable gain amplifier, 5... Keyboard, 6... Generator.
Assigner, 7... Musical tone signal generation channel, 8...
Gate amplifier, 11...envelope signal generator.

Claims (1)

[Claims] 1. A music instrument having a plurality of keys provided corresponding to pitches and one or more musical tone signal generation channels,
These musical tone signal generation channels are assigned to each pressed key, and are supplied with a key depression signal indicating the pressed/released state of the assigned key and pitch data corresponding to that key. In an electronic musical instrument configured to generate a pitched musical tone signal in response to the key press signal, there is provided a volume control device for setting the musical tone volume, and volume level information corresponding to the setting state of the volume control device. a volume level signal generator that generates a volume level signal with An envelope signal generator for generating a signal is provided, one for each of the musical tone signal generation channels, and a key depression signal supplied to the corresponding musical tone signal generation channel indicates a "key depression state". When the key press signal indicates a "key released state", the volume level signal changes from the "key pressed state" to the "key released state". track and hold circuits that output temporarily stored signals, and an amplification gain based on the volume level information of the output signal of the corresponding track and hold circuit, which is provided one for each of the track and hold circuits. and a variable gain amplifier that amplifies the corresponding envelope signal,
A gate amplifier is provided corresponding to each of the variable gain amplifiers and amplifies the output musical tone signal of the corresponding musical tone signal generation channel with a gain corresponding to the output signal of the corresponding variable gain amplifier. , when the key is pressed, the volume of the musical tone of the pitch corresponding to the pressed key depends on the setting state of the volume controller mentioned above, and when the key is released, the volume is controlled at the time of key release. A volume control device characterized in that it is configured to depend on a setting state of a device. 2. The volume control device according to claim 1, wherein the volume controller is an expression pedal. 3. In claim 1 or 2, the volume level signal is an analog DC voltage signal, and the track/hold circuit amplifies the volume level signal voltage when the key press signal is in the "key pressed state". output,
When the key is released, the analog track hold circuit maintains and outputs the output voltage at the time when the key pressed state changes to the key released state.
A volume control device that is a voltage-controlled gain amplifier whose gain is controlled by the output voltage of a hold circuit. 4. In claim 1 or 2, the volume level signal is a digital signal represented by a binary logic voltage, and the track/hold circuit adjusts the volume level to the above volume level when the key press signal is in the "key pressed state". It is a transparent latch circuit that buffers the signal and outputs it, and when the key is in the "key release state", latches and outputs the above-mentioned volume level signal at the time when the "key press state" changes to the "key release state", and it is a variable gain amplifier. is a digitally controlled gain amplifier whose gain is set by the output digital signal value of the transparent latch circuit.