JPS5830594B2 - Double tone fuzz circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit that generates a fuzz sound, and particularly to a multitone fuzz circuit that generates a fuzz sound in a multitone musical instrument such as an electronic organ.

Conventionally, an electric guitar outputs a musical sound signal to produce a so-called fuzz sound by distorting it.

However, when the output signal of an instrument that plays multiple notes, such as an electronic organ, is distorted in order to generate this fuzz sound, a large amount of so-called difference tones are generated, and a harsh component appears in the low range. .

Also, for sustained sounds such as an organ, producing a sustained fuzz can be harsh.

The present invention aims to eliminate or alleviate these drawbacks.

FIG. 1 is a block diagram of an embodiment of the invention.

A tone generator circuit 1 that generates a plurality of scale signals is coupled to a keyboard circuit 2, and a desired one of the plurality of scale signals is extracted based on the operation of a key.

The output signal of the keyboard circuit 2 is applied to a tone color circuit 3 to impart a desired tone color.

If the scale signal of the tone generator circuit 1 has already been appropriately timbre-colored, the timbre circuit 3 may be a simple amplifier.

The above is the configuration of a known electronic organ.

The output signal of the tone circuit 3 is applied to the fuzz circuit 4.

The fuzz circuit 4 may be a high gain amplifier, a Schmitt trigger circuit, or any other nonlinear circuit.

The output signal of the fuzz circuit 4 is applied to a gate typified by, for example, a clip-type sustain gate.

An envelope signal generation circuit 6 is connected to the control terminal of the gate 5.
The envelope signal output from the fuzz circuit 4 is inputted, and the output signal of the fuzz circuit 4 is amplitude-modulated.

The output signal of gate 5 is applied to high-pass filter 7.

The high-pass filter 7 includes a first high-pass filter including a capacitor CH and a resistor R.

Capacitor CH and resistor R1 differentiate the output signal of gate 5 to create a pulse-like signal.

Diode D. and resistor R2 extracts only a half wave of this pulse signal.

Capacitor CL and resistor R3 constitute a second high-pass filter.

The output signal of the high frequency converter 7 and the output signal of the tone circuit 3 are as follows.
The signals are mixed in an adder circuit 8 and an output signal 9 is obtained.

In the above configuration, the output signal of the timbre circuit 3 is a signal from which high frequency components have been considerably removed, but the fuzz circuit 4 distorts this signal to generate a large amount of harmonic components.

This component is the source of the fuzz effect.

However, the fuzz circuit 4 simultaneously generates a large amount of difference tone components.

This component is essentially unnecessary.

The gate 5 may pass these harmonic components and difference tone components by only changing their amplitude, or may pass them through the high-pass filter 7.
Since the difference tone component is removed in , the desired harmonic component, ie, the source of the fuzz effect, appears at the output of the high-pass filter 7.

Add this output to a filter (not shown) if necessary.
It can be made into a fuzz sound.

The gate 5 is turned ON only immediately after the key is pressed, and then rapidly turned OFF.

Therefore, the fuzz effect is added only to the beginning of the musical tone.

This is, so to speak, an attack fuzz, and can be said to be unprecedented.

In the embodiment shown in FIG. 1, the output signal of the tone circuit 3 is input to the fuzz circuit 4, but the output signal of the keyboard circuit 2 may be directly applied to the input of the fuzz circuit 4.

FIG. 2 shows a specific configuration example of the envelope generating circuit 6 and gate 5 in FIG. 1.

The envelope generating circuit 6 receives a key ON pulse obtained from the keyboard circuit 2 at a terminal 10.

The key ON pulse triggers the monostable multibiflator 11 to generate a narrow pulse (approximately 10 m5ec).

Since this pulse charges the capacitor CE via the diode D, the envelope signal vE rises rapidly and after the pulse disappears, it decays according to the time constants CE and RD.

This envelope signal vE is applied to the control terminal of gate 5.

On the other hand, the output signal of the tone circuit 3 is applied from the terminal 12 to the gate 5 via the fuzz circuit 4.

Gate 5 is resistor RB, R,. A well-known structure consisting of RE, Ro and a transistor Q may be used.

The gate 5 amplitude-modulates the output signal of the fuzz circuit 4, for example, a square wave signal, using the envelope signal v0, and outputs the modulated signal to the output terminal 13.

In the embodiment shown in FIG. 1, the fuzz circuit 4, the clip-type gate 5, and the high-pass filter 7 are connected in cascade in this order, but the cascade order is not limited to this order.

FIG. 3 is an example in which the order is changed.

That is, in FIG. 3, the fuzz circuit 4, high-pass filter 15, and multiplier 16 are connected in cascade.

The multiplier 16 is a so-called linear gate, and multiplies the output signal of the high frequency converter 15 and the envelope signal applied to the control terminal 14.

Note that the input terminal of the adder 8 in FIG. 1 may include a filter that changes or changes the frequency component of each input signal.

As a filter, even one with fixed frequency characteristics,
It may be one whose frequency characteristics change over time.

Further, in FIG. 1, the output signal of the gate 5 is generally close to a square wave with a duty ratio of 1/2.

In this case, if only the differentiation is performed, there will be many odd-order harmonics and no even-order harmonics, but the diode D inside the high-pass filter 7.

By clipping only half waves, even-order harmonics are actively generated, which has the effect of making the fuzz sound richer.

Of course, if full wave rectification is used, there will be even more double and even harmonics.

As described above, the present invention is useful when creating a fuzz sound by distorting the output signal of a compound instrument such as an electronic organ.
Differentiate the distorted waveform to remove the difference sound component, and
By adding a percussive envelope to create an attack fuzz effect, it is possible to apply the fuzz effect to the above-mentioned compound instrument, and it is possible to significantly reduce the unpleasant unpleasantness of conventional harsh sounds. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG.
The figure is a circuit diagram showing the main parts of another embodiment. 4...Fuzz circuit, 5...Gate circuit, 7...High-pass filter, 8...Addition circuit, 6... Envelope generation circuit.

Claims (1)

[Scope of Claims] 1. A sound source circuit that generates a plurality of scale signals, a keyboard circuit that inputs the plurality of scale signals and extracts a desired one of them, and a timbre that receives the output signal of the keyboard circuit and gives a tone color. a fuzz processing circuit that receives the output signal of the timbre circuit or the keyboard circuit and generates a fuzz sound, and an adder circuit that mixes the output signal of the timbre circuit and the output signal of the fuzz processing circuit to create a musical tone signal. and an envelope signal generation circuit that generates a percussive envelope signal when a key is pressed; and a gate that modulates the amplitude of one of the outputs of the fuzz circuit or the high frequency modulator in accordance with the envelope signal, and the fuzz tone component is included in the musical tone signal at the start of key depression. If the key is continued to be pressed, the fuzz sound component gradually disappears as time passes by forming the percup type envelope, and the low-frequency difference sound component of the output signal of the fuzz processing circuit is changed to the above-mentioned high pitch. A multitone fuzz circuit characterized by blocking the tones using a region filter. 2. A multitone fuzz circuit as set forth in claim 1, characterized in that a clip circuit for half-wave or full-wave rectification of the output of the high-pass filter is provided as a part of the fuzz processing circuit. 3. The multitone fuzz circuit as set forth in claim 1, wherein the adder circuit has a filter characteristic that changes or changes the frequency of at least one of the two input signals to be mixed.