JPS5837105Y2 - Tone forming device for electronic musical instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a musical tone forming device for an electronic musical instrument, in particular, which allows the rise of a musical tone to be expressed effectively.

An electronic musical instrument is equipped with a sound source device, and the sound source device generates a sound source signal of a frequency corresponding to the pitch of the operated key as a key is operated.

This sound source signal consists of a frequency signal such as a sawtooth wave, a triangular wave, a rectangular wave, or even a sine wave, and this sound source signal is supplied to a low-pass filter to control the content state of harmonic components contained in the sound source signal. By doing so, an arbitrary tone color shape is generated and a musical tone signal is generated.

This musical tone signal is then appropriately amplified and guided to a speaker circuit, where it is produced as a performance sound.

In this case, sawtooth waves, rectangular waves, etc. are effectively used as sound source signals to contain many harmonic components and to form effective musical tones. Passing it through a low-pass filter for formation essentially integrates the input signal, eg, the input sawtooth signal.

That is, the crest of the sawtooth wave signal becomes rounded, and the waveform becomes rounded especially at the rising edge of a musical tone, making it impossible to express a sharp rising edge of a musical tone.

This invention improves the above-mentioned drawbacks, especially in the rising part of a musical tone, which contains more harmonic components than a normal playing part, so that the expression of the rising part of a musical tone can be clearly expressed. This is intended to provide a musical tone forming device for electronic musical instruments, which uses a low-pass filter whose cut-off frequency is variably controlled to form the tone, and generates a control pulse signal with a pulse width corresponding to the pitch of the pressed key as well as the pressed key. occurs,
This control pulse signal is used to variably control the cutoff frequency of the low-pass filter in a higher direction.

An embodiment of this invention will be described below with reference to the drawings.

The attached drawing shows its configuration. Reference numeral 11 denotes a keyboard circuit, and from this keyboard circuit 11, a pitch signal KV of a voltage value corresponding to the pitch of the operated key and a key press/release are output from the keyboard circuit 11. A keying signal KON corresponding to the key operation is generated.

The pitch signal KV generated by the keyboard circuit 11 is supplied to a voltage-controlled variable frequency oscillator 12 (hereinafter abbreviated as CO), so that this VCO 12 generates a sound source signal with a frequency corresponding to the pitch signal. In this case, VCO1
From No. 2, a sound source signal with a sawtooth wave containing many harmonic components is generated.

The sound source signal generated by the VCO 12 is passed through a low-pass filter L.
Voltage controlled variable filter 13 (hereinafter referred to as VC) constituting the PF
(abbreviated as "F") and forms a tone by controlling the content of harmonic components to produce a musical tone signal.

The musical tone signal from the VCF 13 is subjected to open/close envelope control by a voltage-controlled variable gain amplifier 14 (hereinafter abbreviated as VCA), appropriately amplified by an amplifier 15, and then supplied to a speaker 16, where it is produced as a performance sound. Do it like this.

Envelope waveform signals are supplied as control signals to the VCF 13 and VCA 14 from envelope generation circuits 17 and 18, respectively.

The envelope generating circuits 17 and 18 are supplied with the keying signal KON from the keyboard circuit 11, and generate a waveform signal whose voltage value changes with time, rising and sustaining when a key is pressed, and decaying when the key is released. A plurality of conditions for shaping the waveform, such as a rise time constant, a sustain level, a decay time constant, etc., of the waveform are set in the control circuit 19 using a voltage generation circuit including, for example, a plurality of variable resistors.

That is, in the VCF 13, its cutoff frequency is varied depending on the supplied envelope waveform signal,
The VCA 14 controls the amplification gain in accordance with the envelope waveform, and sets the opening/closing and volume envelope corresponding to the key operation of the output musical tone.

Here, the pitch signal KV is level-controlled and supplied as a control signal to the VCF 13, so that a perceptually uniform tone is formed over the entire tone range.

Furthermore, for the VCF 13, a detection circuit 20
A control pulse signal from the VCF 13 is applied to control the cutoff frequency of the VCF 13 to be rapidly moved in a higher direction.

This detection circuit 20 is composed of a one-shot circuit consisting of, for example, a monostable multivibrator, and the keyboard circuit 11
It takes in the keying signal KON corresponding to a key press and generates a one-shot pulse signal that rises as the key is pressed.The pulse width of this one-shot pulse signal becomes narrower as the pitch increases. The control settings are made using the pitch signal KV obtained from the keyboard circuit 11 as shown in FIG.

The pulse width of this pulse signal corresponds to the time during which the cutoff frequency of the VCF 13 is kept in a high direction.

In this case, it is desirable that the pulse width of the control pulse signal obtained by the detection circuit 20 corresponds to one wave or one wave of the sound source signal obtained from the VCO 12.

That is, according to the musical tone forming device configured as described above, the pitch signal KV is generated from the keyboard circuit 11 as a key is operated on the keyboard section, and the VCO 12 generates a sound source with a frequency corresponding to the pitch of the operated key. A signal is generated.

This sound source signal is then subjected to timbre formation by the VCF 13 in response to an envelope waveform signal controlled by a keying signal KON corresponding to a key operation, envelope-controlled by the VCA 14, and then produced as a performance sound.

In this case, a control pulse signal is generated from the detection circuit 20 when the key is pressed, and the cutoff frequency of the VCF 13 is moved to a higher direction, and while this control pulse exists, the amount of harmonic components included in the musical tone signal is increased. Ru.

That is, at the rising edge of the musical tone played, a sharp sound of the performer containing many harmonic components is expressed, and the timbre is effectively emphasized from the rising edge of the musical tone.

Here, the pulse width of the control pulse signal obtained by the detection circuit 20 is controlled in accordance with the pitch of the performance sound, that is, the pulse width is controlled to be large in the bass part and small in the treble part. Therefore, particularly sharp musical tones are audibly expressed effectively in the treble range, and rising part emphasis control can be effectively executed over the entire range.

Although the sound source signal is shown as a sawtooth wave signal in the embodiment, it can be arbitrarily configured as a rectangular wave or the like as long as it contains a harmonic component.

In addition, the sound source device is not limited to ■CO; for example, a fixed oscillation type that uses a frequency dividing circuit to generate a sound source signal for each pitch and selects it in response to key operation can have the same effect. That's what you get.

As described above, according to this invention, the generation of musical tones is controlled so that a large amount of harmonic components are contained especially in the rising parts of musical tones, and the rising parts of musical sounds to be played can be effectively emphasized. It is.

Therefore, the performance expressiveness of musical tones is significantly improved,
This will have a great effect on improving the expressive power of electronic musical instruments.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawing is a configuration diagram illustrating an electronic musical instrument according to an embodiment of the invention. 11... Keyboard circuit, 12... Voltage controlled variable frequency oscillator, 13... Voltage controlled variable filter (low pass filter), 14... Voltage control type variable gain amplifier, 20...detection circuit.

Claims (1)

[Scope of utility model registration request] A sound source device that generates a sound source signal consisting of a frequency signal including harmonic components in response to a key operation; a low-pass filter whose cutoff frequency is variably controlled to form a tone color from the generated sound source signal; means for generating a control pulse signal having a pulse width corresponding to the pitch of the operated key from the time the key is pressed, and the control pulse signal controls the low-pass filter in a direction in which its cutoff frequency becomes higher. Tone forming device for electronic musical instruments.