JP2017173616A - System and method for generating musical sound signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply fluctuation of a frequency and amplitude with natural feeling to a musical sound signal.SOLUTION: There are provided: a device for vertically fluctuating a frequency of a musical sound signal waveform with a first low frequency noise waveform formed of a frequency component which is less than an audible frequency; and a device for varying amplitude of the musical sound signal waveform with a second low frequency noise waveform formed of a frequency component which is less than the audible frequency.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a system and method for generating a musical tone signal in an electronic musical instrument or the like. More specifically, the present invention relates to a performance of a so-called natural musical instrument by giving irregular fluctuations composed of low frequency components to the frequency and amplitude of the generated musical tone. It is devised so as to generate a musical sound with a more natural feeling like a musical sound that is pronounced.

  In devices that generate musical sound signals using electronic circuits, such as electronic musical instruments, the generated musical sound signals are generally stable in frequency and amplitude. I cannot deny it. For this reason, a vibrato effect is provided by shaking the frequency of the musical signal up and down with a vibrato alternating waveform with a frequency of, for example, 6 to 8 Hz, or a transitional amplitude is applied to the rising, continuing, and falling portions of each musical sound to be played. Various ideas have been adopted that change the frequency and amplitude of the generated musical sound in time, such as by giving a change.

  The vibrato effect is applied by changing the pitch (frequency) of a musical sound signal to be generated in a sine wave shape up and down around a predetermined pitch, and the variation width (vibrato depth) is generally 1/6 semitone. (About 17 cents) and the change frequency is often 6 to 8 Hz. When a vibrato effect is added to a musical sound, richness is added to the sound as it is heard, and the natural feeling increases. However, because the frequency fluctuation is a stable sine wave, there is still a lack of natural feeling. In addition, when a transitional amplitude change is applied to the rising, sustaining, and falling parts of each musical sound that is played, the sounding is opened and closed with a natural feeling. If the musical tone is uniform, you can't wipe out the feeling of lack of naturalness.

  The present invention provides a system and method for generating a musical sound that makes the user feel more natural by introducing irregularity to the frequency fluctuation of the musical sound to be generated and adding irregular fluctuation to the amplitude of the musical sound to be generated. The purpose is to provide.

  In order to solve the above-described problems, a system for generating a musical tone signal according to the present invention includes a device for generating a musical tone signal waveform having a frequency that determines a predetermined pitch, and a first low-frequency component comprising a frequency component less than an audible frequency. A device that generates a noise waveform, a device that fluctuates the frequency of the musical sound signal waveform with the first low-frequency noise waveform, a device that generates a second low-frequency noise waveform composed of frequency components less than the audible frequency, and And a device for changing the amplitude of the tone signal waveform whose frequency is fluctuated up and down with a second low-frequency noise waveform.

  In addition, the system of the present invention is characterized in that the first low-frequency noise waveform and the second low-frequency noise waveform are noise waveforms each having a frequency component of 0.1 to 12 Hz.

  The system of the present invention further includes a device that generates a vibrato alternating waveform having a frequency that determines the vibrato speed, and the device that fluctuates the frequency of the musical sound signal waveform up and down includes the vibrato alternating waveform and the first waveform. It is characterized in that the frequency of the tone signal waveform is fluctuated up and down with a waveform combined with one low frequency noise waveform.

  Further, the system of the present invention further comprises a device for generating an opening / closing envelope waveform representing a transient shape of a rising portion, a continuous portion, and a falling portion of an envelope when opening / closing a musical sound signal, The apparatus for changing the amplitude of the signal waveform is characterized in that the amplitude of the tone signal waveform is changed by a waveform obtained by combining the open / close envelope waveform and the second low-frequency noise waveform.

  Further, the method for generating a musical sound signal according to the present invention includes a step of generating a musical sound signal waveform having a frequency that determines a predetermined pitch, and a step of generating a first low-frequency noise waveform comprising frequency components less than an audible frequency. The frequency of the tone signal waveform was swung up and down with the first low frequency noise waveform, the step of generating a second low frequency noise waveform composed of frequency components less than the audible frequency, and the frequency was swung up and down. And changing the amplitude of the tone signal waveform with the second low-frequency noise waveform.

  In addition, the method of the present invention is characterized in that the first low frequency noise waveform and the second low frequency noise waveform are noise waveforms each having a frequency component of 0.1 to 12 Hz.

  The method of the present invention further includes a step of generating a vibrato alternating waveform having a frequency that determines a vibrato speed, and the step of vertically swinging the frequency of the musical sound signal waveform includes the vibrato alternating waveform and the first waveform. It is characterized in that the frequency of the tone signal waveform is fluctuated up and down with a waveform combined with one low frequency noise waveform.

  In addition, the method of the present invention further includes the step of generating an opening / closing envelope waveform representing a transient shape of a rising portion, a continuous portion, and a falling portion of an envelope when opening / closing a musical sound signal, The step of changing the amplitude of the signal waveform is characterized in that the amplitude of the tone signal waveform is changed by a waveform obtained by combining the open / close envelope waveform and the second low-frequency noise waveform.

  According to the present invention, since irregular fluctuation is added to the generated musical sound, it is possible to generate a musical sound that gives a more natural feeling while the musical sound is generated by the electronic circuit.

It is a block diagram which shows the structure of 1st embodiment of this invention. It is a block diagram which shows the structure of 2nd Embodiment of this invention. FIG. 3 is a waveform diagram of an open / close envelope waveform used in the embodiment of FIG. 2. It is a block diagram which shows the structure of the electronic musical instrument using 2nd embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described. In order to explain the principle of generating a tone signal according to the present invention, first, as a first embodiment, frequency fluctuation and amplitude fluctuation are added to a tone signal as a continuous sound. The configuration to be given will be described with reference to FIG. FIG. 1 shows a system for generating a musical sound signal by a sound source waveform memory reading method. The sound source waveform memory 1 generates a waveform corresponding to one period (2π radians) of a musical sound to be generated at each phase point (for example, phase of 65536 points). Is stored as a sequence of sample values of wave heights at (address), and a tone signal at that frequency is generated by sequentially reading the peak values with a phase address signal that advances at a speed corresponding to the frequency of the tone signal to be generated. . For example, when generating a tone signal at a sampling frequency of 44.1 kHz, to generate a tone signal of 523.251 Hz, an average of 65536 × 523.251 / 44100 = 777.59 increments per sample is used. The sound source waveform memory 1 is accessed by the stepping address signal (the address itself is a value of only the integer part), and the waveform sample values are read out at a rate of 44,100 per second. As the phase increment value, a value (for example, 777.559) corresponding to the frequency (for example, 523.251 Hz) of each musical tone is stored in the phase increment value memory 2, and it corresponds to the pitch of the musical tone to be generated. A predetermined value is read out, and the read phase increment value is accumulated 44,100 times per second in the phase increment value accumulator 3, and a phase value that increases with time as a result of the accumulation is a musical sound waveform. It is output as a step address signal for reading out the memory 1.

  In FIG. 1, a frequency fluctuation imparting device 4 characterized by the present invention is provided between the phase increment value memory 2 and the phase increment value accumulator 3, and the phase increment value read from the phase increment value memory 2 is provided. Is supplied to the phase increment value accumulator 3 by swinging up and down (increase / decrease with time). As a result, the stepping speed of the stepping address signal read from the sound source waveform memory 1 is fluctuated, and the frequency of the read tone signal is fluctuated up and down. Here, the frequency fluctuation imparting device 4 includes a low frequency irregular noise generator 41, a fluctuation width adjuster 42, and a multiplier 43. The low frequency irregular noise generator 41 has a frequency component (less than an audible frequency ( For example, a low frequency noise waveform having a frequency component of less than 12 Hz) is generated as a digital value, and the waveform is irregular with a maximum fluctuation width of 0.99 to 1.01 centering on 1.00. It is a waveform that fluctuates. This is a random noise waveform that contains only a frequency component less than the audible frequency in so-called white noise as an active component. The swing width adjuster 42 has a maximum swing width (± 0.01 centered around 1.00) of the low frequency noise waveform output from the low frequency random noise generator 41 in the range of 0 to 0.01. To adjust the frequency fluctuation of the tone signal to be generated. The multiplier 43 multiplies the phase increment value output from the phase increment value memory 2 by the value of the low-frequency noise waveform whose amplitude is adjusted, and varies the phase increment value. As a result, the stepping speed of the stepping address signal output from the phase increment value accumulator 3 increases / decreases within the range of the standard speed ± 0 to 0.01, and the tone signal read from the sound source waveform memory 1 is increased. The frequency is swung up and down with a standard pitch ± 0 to 0.01. When expressed in units of pitch measurement, this fluctuation width corresponds to a standard pitch of ± 0 to 17 cents.

  In FIG. 1, an amplitude change imparting device 5 characterized by the present invention is further provided on the output side of the sound source waveform memory 1, and the output point is changed by changing the amplitude of the tone signal read from the sound source waveform memory 1. 6 is output. Here, the amplitude change imparting device 5 includes a low-frequency random noise generator 51, a change width adjuster 52, and a multiplier 53. The low-frequency random noise generator 51 generates a frequency component less than the audible frequency. A low-frequency noise waveform is generated as a digital value, and the waveform is a waveform that irregularly changes with a maximum amplitude of 0.80 to 1.20 centering on 1.00. This is a random noise waveform that contains only a frequency component less than the audible frequency in so-called white noise as an active component. The change width adjuster 52 sets the change width (± 0.20 width centered on 1.00) of the low frequency noise waveform output from the low frequency random noise generator 51 in the range of 0 to 0.20. It adjusts the degree of change in the amplitude of the tone signal to be output to the output point 6. The multiplier 53 multiplies the sample value of the tone signal waveform output from the sound source waveform memory 1 by the adjusted value of the low frequency noise waveform, and sets the amplitude of the tone signal appearing at the output point 6 to ± 0 to 20%. Change irregularly in width.

  In the embodiment of FIG. 1, as the frequency components of the low-frequency noise waveform generated by the low-frequency random noise generators 41 and 51, the components in the range of 0.1 to 12 Hz are naturally fluctuated in the experiments of the inventors. It was suitable in terms of giving the feeling.

  Next, in order to explain the case where the principle of generating a musical tone signal according to the present invention is used in an electronic musical instrument, as a second embodiment, a vibrato effect is added and a sound key opening / closing function (on / off) is added. The configuration will be described with reference to FIG. FIG. 2 is a system for generating a musical sound signal by a sound source waveform memory reading method as in FIG. 1. In this embodiment, the frequency fluctuation applying device 4 includes a vibrato AC waveform generator 46 and a vibrato depth adjuster 47. And an adder 48 are additionally provided. The vibrato AC waveform generator 46 generates an AC waveform having a vibrato frequency (for example, 7 Hz) which is a vibrato speed, and the waveform has a maximum fluctuation width of 0.99 to 1.01 centering on a value of 1.00. It is a sine wave that fluctuates regularly. The vibrato depth adjuster 47 adjusts the amplitude of the sine wave output from the vibrato alternating-current waveform generator 46 (± 0.01 centered around 1.00) within a range of 0 to 0.01, and vibrato. Is adjusted (the degree of fluctuation of the frequency of the musical sound signal to be generated). The adder 48 adds the adjusted low frequency noise waveform from the previous amplitude adjuster 42 and the adjusted vibrato AC waveform from the current vibrato depth adjuster 47, and uses the combined waveform. In the multiplier 43, the phase increment value output from the phase increment value memory 2 is increased or decreased. As a result, the music signal read from the sound source waveform memory 1 is subjected to vibrato in a waveform in which a vibrato AC waveform and a low-frequency noise waveform are combined. As a result, it is possible to expect a vibrato effect with a fluctuation that makes the user feel more natural than a vibrato using a simple sine wave. When both the swing width adjuster 42 and the vibrato depth adjuster 47 are adjusted to “level = 0”, a musical sound signal without vibrato is generated. Further, when not using the irregular frequency fluctuation according to the present invention but using only the regular regular vibrato effect, the fluctuation width adjuster 42 is adjusted to “level = 0” and the vibrato depth adjuster 47 is adjusted. This can be realized by adjusting to a desired level.

  Further, in the embodiment of FIG. 2, an opening / closing envelope waveform generator 56 and a multiplier 58 are additionally provided in the amplitude change applying device 5. The open / close envelope waveform generator 56 is also commonly referred to as an “envelope generator”, and opens and closes a musical tone signal while applying a transient amplitude change to the rising portion, continuous portion, and falling portion of each musical tone to be played. As shown in FIG. 3, the waveform is generated at an attack rising part A that starts with key-on, an attack return part B, and then continues at a constant amplitude while being depressed. A waveform having a continuation portion C that starts and a decay portion D that starts with key-off. If it is not necessary to make the attack part conspicuous during pronunciation, the attack return part B is omitted. In order to express a plucked musical instrument-like performance effect, an envelope is used in which the decay portion D immediately follows the attack rising portion A. The multiplier 58 multiplies the envelope waveform from the envelope waveform generator 56 by the adjusted low frequency noise waveform from the previous change width adjuster 52, and obtains the peak value of the envelope waveform shown in FIG. Randomly increase / decrease within an adjusted range within ± 20% to give fluctuation to the shape of the envelope waveform. The musical tone signal read from the sound source waveform memory 1 is opened and closed by the multiplier 53 with the envelope waveform to which the fluctuation is applied. When the change width adjuster 52 is adjusted to “level = 0”, a tone signal that is opened and closed with a normal opening and closing envelope waveform without irregular amplitude fluctuation appears at the output point 6.

  Next, a configuration when the second embodiment is used for a multi-tone electronic musical instrument capable of generating a plurality of musical sounds at the same time will be described with reference to FIG. This electronic musical instrument has a plurality of time-division channels corresponding to the maximum allowable number of sounding keys (for example, 16 keys) and performs a time-sharing operation. When a performance sound key is pressed on the keyboard 81, a time-division sound channel responsible for the sound of the key is secured in the channel assigner 82, and a tone signal as shown in FIG. Is called. The phase increment value corresponding to the depressed key is read from the phase increment value memory 2 and sent to the frequency fluctuation imparting device 4, and the vibrato AC waveform and the fluctuation width adjuster adjusted by the vibrato depth adjuster 47. A value obtained by adding the low frequency noise waveform adjusted by 42 by the adder 48 is multiplied by the phase increment value by the multiplier 43, and the multiplied value is accumulated at the sampling frequency by the phase increment value accumulator 3. As a step address signal, the sound source waveform memory 1 is read out.

  On the other hand, a key-on signal sent as the sound generation channel is secured by the key depression is supplied to the opening / closing envelope waveform generator 56, and the generation of the opening / closing envelope waveform shown in FIG. Subsequently, the process proceeds to the sustaining part C via the attack return part B, and then the sustaining part C is maintained while the key is pressed, and the decay part D starts when the key-off signal is received by the key release. . The open / close envelope waveform is separately generated by the low frequency random noise generator 51 and level-adjusted to a range of ± 0 to 20% by the change width adjuster 52, and by the multiplier 58. Multiplication is performed to modulate the amplitude of the tone signal read from the sound source waveform memory 1 with the multiplied envelope waveform. That is, the signal appears at the output point 6 after being opened and closed with an amplitude shape in which irregular fluctuations due to the low frequency noise waveform are added to the original opening and closing envelope shape.

  As described above, the sample value of the tone signal generated at each of the time division tone generation channels and appearing at the output point 6 is sampled by the channel accumulator 83 for all the time division channels in order to match the tone at the entire electronic musical instrument. Are sequentially accumulated to form a sequence of total sample values, and are thereafter released into the air as performance musical sounds via the digital-analog converter 84, the amplifier 85, and the speaker 86.

  As can be understood from the above description, according to the present invention, the generated musical sound is added with irregular fluctuations of a moderate frequency less than the audible frequency and irregular fluctuations of the amplitude, so that it is more natural. Sounds like a musical tone.

  DESCRIPTION OF SYMBOLS 1 ... Sound source waveform memory, 2 ... Phase increment value memory, 3 ... Phase increment value accumulator, 4 ... Frequency fluctuation provision apparatus, 5 ... Amplitude change provision apparatus, 6 ... Output point, 41 ... Low frequency irregular noise generator 42 ... Swing width adjuster, 43 ... Multiplier, 46 ... Vibrato AC waveform generator, 47 ... Vibrato depth adjuster, 48 ... Adder, 51 ... Low frequency random noise generator, 52 ... Change width adjuster 53 ... Multiplier, 56 ... Open / close envelope waveform generator, 58 ... Multiplier, 81 ... Keyboard, 82 ... Channel assigner, 83 ... Channel accumulator, 84 ... Digital-analog converter, 85 ... Amplifier, 86 ... Speaker A ... Attack rising part, B ... Attack return part, C ... Sustain part, D ... Decay part.

Claims (8)

A device for generating a tone signal waveform having a frequency that determines a predetermined pitch;
An apparatus for generating a first low-frequency noise waveform comprising a frequency component less than an audible frequency;
An apparatus for swinging the frequency of the musical sound signal waveform up and down with the first low-frequency noise waveform;
An apparatus for generating a second low-frequency noise waveform comprising a frequency component less than an audible frequency;
A system for generating a frequency-modulated and amplitude-modulated musical sound signal, comprising: an apparatus for changing the amplitude of a musical sound signal waveform whose frequency is fluctuated up and down with the second low-frequency noise waveform. The system for generating a musical sound signal according to claim 1,
The first low-frequency noise waveform and the second low-frequency noise waveform are noise waveforms each having a frequency component of 0.1 to 12 Hz. A system for generating a musical sound signal according to claim 1 or 2, further comprising:
It is equipped with a device that generates a vibrato AC waveform with a frequency that determines the speed of vibrato,
The apparatus for vertically swinging the frequency of the tone signal waveform is characterized by swinging the frequency of the tone signal waveform up and down with a waveform that combines the vibrato alternating current waveform and the first low-frequency noise waveform. system. A system for generating a musical sound signal according to claim 3, further comprising:
Comprising a device for generating an opening / closing envelope waveform representing a transitional shape of the rising part, the continuous part, and the falling part of the envelope when opening and closing the musical sound signal;
The apparatus for changing the amplitude of the musical tone signal waveform is a system for changing the amplitude of the musical tone signal waveform with a waveform obtained by combining the open / close envelope waveform and the second low frequency noise waveform. . Generating a tone signal waveform having a frequency that determines a predetermined pitch;
Generating a first low frequency noise waveform comprising frequency components less than the audible frequency;
Swinging the frequency of the tone signal waveform up and down with the first low frequency noise waveform;
Generating a second low frequency noise waveform comprising frequency components less than the audible frequency;
A method of generating a frequency-modulated and amplitude-modulated musical sound signal comprising: changing an amplitude of a musical sound signal waveform whose frequency is fluctuated up and down with the second low-frequency noise waveform. The method for generating a musical sound signal according to claim 5,
The first low-frequency noise waveform and the second low-frequency noise waveform are noise waveforms each having a frequency component of 0.1 to 12 Hz. A method for generating a musical sound signal according to claim 5 or 6, further comprising:
Generating a vibrato alternating waveform with a frequency that determines the speed of the vibrato,
The step of swinging the frequency of the tone signal waveform up and down is a step of swinging the frequency of the tone signal waveform up and down with a waveform that combines the vibrato alternating current waveform and the first low-frequency noise waveform. Method. A method for generating a musical sound signal according to claim 7, further comprising:
Generating an opening and closing envelope waveform representing a transitional shape of the rising part, the continuous part, and the falling part of the envelope when opening and closing the tone signal;
The step of changing the amplitude of the tone signal waveform is a step of changing the amplitude of the tone signal waveform with a waveform obtained by combining the open / close envelope waveform and the second low frequency noise waveform. .

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