JPH096364A - Musical tone generating method - Google Patents

Abstract

PURPOSE: To allow a wasteful musical tone waveform calculation not to be executed. CONSTITUTION: In the waveform data in one pronunciation, since higher harmonics are much included in the attack part, many waveform samples are generated through calculation before a time t2 by making a calculation cycle short. Then, in the part including the duaration part from the time t2 till a time t4, the number of waveform samples to be generated through calculation is made to be a half by making the calculation cycle a half. Moreover, in the part after a time t4 in which the higher harmonics are almost attenuated, the number of waveform samples to be generated through calculation is made to be a quarter by making the calculation cycle a quarter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical tone generating method for generating a musical tone waveform sample by waveform calculation of an arithmetic processing unit.

[0002]

2. Description of the Related Art In a sound source capable of simultaneously producing a plurality of channels in which a musical tone waveform sample is generated by a waveform generating calculation using a conventional arithmetic processing unit, a waveform sample is calculated and generated per unit time in each musical tone generating channel. Is constant for each sound source. Further, the waveform calculation cycle for calculating the tone waveform sample is fixed even during one sound generation, and the waveform calculation cycle is not changed during one sound generation.

Here, the defined "arithmetic cycle" is
It is a measure of the characteristic idea of the present invention. Operation cycle,
That is, if the number of samples calculated and generated per unit time is different, naturally the upper limit frequency of the frequency band that can be contained in the generated musical sound is also different. If the calculation cycle is converted into the number of samples generated per second (equivalent sampling frequency), the upper limit is approximately half the frequency according to the sampling theorem. For example, when performing arithmetic generation of 128 samples every unit time of 1/375 seconds, the equivalent sampling frequency is 128 × 37.
Since 5 = 48 (kHz), the generated musical tone can have frequency components up to about 24 (kHz) which is the upper limit. Generally, the sampling frequency is a factor that determines the quality of digital musical tones, and therefore the quality of musical tones depends on the operation cycle.

On the other hand, this calculation cycle is directly reflected on the calculation amount per unit time of the tone generation calculation. 1
Since the calculation performed in the generation of the musical sound for the sample does not change so much for each sample, the required calculation amount also increases substantially in proportion to the number of samples calculated and generated per unit time. That is, if the calculation cycle is increased to improve the quality of the musical tone, the required calculation amount increases and the circuit scale increases. In some cases, it becomes impossible to perform computations, which are incompatible with each other, and how to balance them is a key point when designing a sound source.

[0005]

However, the frequency band of the tone waveform generated in each tone generation channel is generally different depending on the tone color of each tone, etc.
If the waveform calculation cycle in each tone generation channel is constant like the above-described conventional sound source, a channel that generates a tone waveform that does not require a wide band will perform wasteful calculation up to an unnecessary frequency band. There was a problem. In addition, when the waveform calculation cycle is set in accordance with a tone waveform that does not require a wide band, there is a problem that a tone waveform sample that requires a wide band cannot be generated.

Further, the musical tone waveform of one sound of the attenuated sound system is in a wide band because many harmonics are included in the attack part thereof, but there are few harmonics in the sustained part where the attenuation is advanced and the band is too wide. It has not been. In this case, if the waveform calculation cycle for calculating the musical tone waveform sample during one sound generation is fixed as in the conventional case, useless calculation up to an unnecessary frequency band is performed in a portion where a wide band is not needed during one sound generation. There was a problem that this would happen. In addition, when the waveform calculation cycle is set in accordance with a portion that does not require a wide band, there is a problem that a portion that requires a wide band cannot be generated.

In view of the above, the present invention aims to prevent unnecessary calculation in a musical tone generating method for generating a musical tone waveform sample by waveform calculation of an arithmetic processing unit and to efficiently generate a wide band musical tone waveform sample. Has an aim.

[0008]

In order to achieve the above object, the tone generating method of the present invention is a tone generating method for generating tone waveform samples by waveform calculation of an arithmetic processing unit, wherein the waveform calculation cycle of the waveform calculation is Is determined for each tone generation channel according to the characteristics of the waveform of each tone generation channel of the generated musical tone waveform sample and the importance of each tone generation channel. Another musical tone generating method of the present invention is the musical tone generating method for generating a musical tone waveform sample by waveform calculation of an arithmetic processing unit.
The waveform calculation cycle of the waveform calculation is changed in the middle of one sound generation according to the content ratio of the higher harmonic wave which changes with the passage of time in the tone waveform sample during sound generation.

Furthermore, still another tone generation method of the present invention performs the tone generation calculation for a plurality of tone generation channels to generate waveform data of a plurality of tone tones corresponding to the plurality of tone generation channels (1) to (1) below. It includes the step (4). (1) A tone control step of generating first control data for instructing, for each tone generation channel, the characteristics of the tone generated by the plurality of tone generation channels. (2) The number of samples of tone generated per unit time,
Arithmetic control step for generating second control data instructing each tone generation channel (3) For the plurality of tone generation channels, waveform data of musical tones corresponding to each tone generation channel is set according to the tone characteristic instructed by the first control data. And a step of generating a sound based on the waveform data of a plurality of channels generated in the step of generating a musical tone, which is calculated and generated at the sample generation speed indicated by the second control data.

In the musical tone generating method, the arithmetic control step is adapted to generate the second control data in correspondence with the musical tone characteristics of the waveform data generated in each tone generation channel. The step is adapted to change the generated second control data in response to the time change of the musical tone characteristics of the waveform data generated in each sound generation channel, and further, the first control data includes: Pitch information that specifies the pitch of the musical sound to be generated in each sounding channel is included, and in the musical sound generating step, the pitch information of each sounding channel is set in accordance with the sample generation speed instructed by the second control data. It is adapted to be converted into the phase change speed of the generated musical sound.

Furthermore, the tone generating method of the present invention includes the following steps (1) to (5) for simultaneously generating at least two tones. (1) A first generation step of generating a first musical tone waveform sample containing many high frequency components at a generation rate of N samples per unit time (2) A second musical tone waveform sample having few high frequency components Second generation step of generating at a generation rate of M samples (where M <N) (3) Interpolating the second musical tone waveform of the M samples to obtain N
Conversion step of converting to a second musical tone waveform of the sample (4) Mixing step of sequentially adding the first musical tone waveform of the N samples and the second musical tone waveform of the N samples to obtain a mixed musical tone waveform of N samples (5) A step of generating a sound based on the mixed tone waveform obtained in the mixing step

Furthermore, the tone generation method of the present invention performs tone generation calculation for a plurality of tone generation channels to generate waveform data of a plurality of tone sounds corresponding to the plurality of tone generation channels (1) to (6) below. It includes the steps of. (1) Dividing step for dividing the plurality of sound generation channels into a first group and a second group (2) For each sound generation channel of the first group, N tone musical sound waveforms are generated for each unit time, A first generation step of sequentially adding N channels and outputting a first mixed waveform of N samples (3) For each sound generation channel of the second group, a musical tone waveform of M (M <N) samples per unit time Produces
Second addition for M samples by sequentially adding over multiple channels
Second generation step of outputting mixed waveform (4) Interpolating the second mixed waveform of the M samples to obtain N
Converting step of converting to a second mixed waveform of samples (5) Mixing step of sequentially adding the first mixed waveform of the N samples and the second mixed waveform of the N samples for each sample to obtain a mixed tone waveform of N samples (6) Step of generating sound based on the mixed tone waveform obtained in the mixing step

[0013]

According to the present invention, the waveform calculation cycle can be determined for each sounding channel depending on whether or not the musical tone waveform to be sounded has a wide band or according to the degree of importance. Alternatively, regardless of the narrow band, it is possible to generate a musical tone waveform sample without causing unnecessary waveform calculation. In the case of a damped sound system, 1
In the attack section during sound generation, the waveform calculation cycle is increased to generate many waveform samples in a small amount, and in the sustain section, the waveform calculation cycle is decreased to generate waveform samples, so that unnecessary waveform calculation does not occur. The waveform sample can be efficiently generated.

As described above, since it is possible to save the waveform calculation in a specific tone generation channel, it is possible to increase the waveform calculation amount of the musical tone waveform of the other channels.
You can improve the tone quality of that channel or increase the number of sound channels. Furthermore, since it is possible to control the number of generated musical sound samples per unit time independently for each sound generation channel, it becomes possible to give a difference in quality of generated musical sound between sound generation channels. In addition, it is possible to reduce the calculation amount of the sound generation channel that is less affected even if the quality is low.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the configuration of a musical tone generating apparatus capable of executing the musical tone generating method of the present invention. In this figure, reference numeral 1 is an arithmetic processing unit (CPU) that executes an application program or the like to perform various kinds of control such as generation of musical tone waveform samples, and 2 is a read / write unit in which an operation program of the CPU, preset tone color data, etc. are stored. Only memory (ROM), 3 is a random access memory (RAM) having a storage area such as a work memory area and tone color data area of the CPU 1, and 4 is a time instruction and a timer interrupt processing timing to the CPU 1. A timer for indicating 5 is a MIDI interface for inputting a MIDI event and outputting the generated MIDI event. Reference numeral 6 is a so-called personal computer keyboard provided with letters, kana, numbers, symbols and the like.

Reference numeral 7 is a display (monitor) for the user to interact with the musical tone generating apparatus, and 8 is a pre-installed application program such as a musical tone generating program and the musical tone used for generating the musical tone waveform sample. A hard disk (HDD) in which waveform data and the like are recorded, and 9 is an RA designated by the CPU 1.
The data of the musical tone waveform sample stored in a part of the area of M3 is directly delivered without passing through the CPU1, and one sample is read at a constant reproduction cycle (reproduction sampling frequency) to obtain a digital-analog converter ( Playback unit (DMA: Direct Memory) supplied to the DAC
Access) 10 is a digital-to-analog converter (DAC) that receives the data of the musical tone waveform sample and converts it into an analog signal, and 11 is a sound system that emits the musical tone signal converted into the analog signal output from the DAC 10.

Next, the structure of the areas of various registers set in the RAM 3 is shown in FIGS. 2 to 5. FIG. 2 shows the structure of the areas in which the tone color data and the waveform data are stored.
FIG. 3 shows the configuration of the input buffer that stores the MIDI message input via the MIDI interface 5, and FIG. 4 shows the configuration of the sound source register that stores various parameters necessary to generate the musical tone waveform sample of each tone generation channel. Is shown. In the area shown in FIG. 2, PD1,
PD2, ... 16 types of tone color data of PD16,
N types of waveform data WD1, WD2, ... WDn are stored. An OPEG waveform described later is prepared for each waveform data, and the waveform data WD1, WD2, ...
-It is stored together with WDn.

The respective tone color data PD1 and PD
2, ... PD 16 is data for designating waveforms in each range (designation of each range waveform), data for controlling LFO (Low Frequency Oscillator) for applying effects such as vibrato (LFO control OD), tone color filter characteristics For controlling the generation of a filter envelope (FEG control OD) for changing the sound volume over time, and for controlling the generation of a sound volume envelope (AEG control O)
D), data for touch control (touch control OD) that changes the rising speed of a musical sound according to velocity, and other data (other OD) such as calculation cycle control data described later.

In the area of the input buffer shown in FIG. 3, note-on, note-off, and various event data ID1, I input via the MIDI interface 5 are input.
D2, ID3, ... Are sequentially written, the MIDI event data ID1, ID2, ID3, ... Are read out, and the event processing is executed in the tone generation device, so that a musical tone waveform sample corresponding to the event is generated. Is generated. The MIDI event data ID1, I
D2, ID3, etc. are configured as a set of the data content of the MIDI event (data 1 etc.) and the time of occurrence of the event data (data 1 occurrence time etc.). This occurrence time can be known by fetching the current time of the timer 4.

The area shown in FIG. 4 is a register (1ch, 2ch, 3ch, etc.) prepared for each tone generation channel in which various tone parameters for controlling tone waveform samples generated in each tone generation channel are stored.・
..32ch) used as a sound source register. In this example, the tone generator register is used when the tone generation channel is 32 channels.

Register for each sound channel (1ch, 2
ch, 3ch, ... 32ch), the note number of the musical sound produced in the sounding channel, waveform designation data (waveform designation D) that designates any of the waveform data stored in the RAM 3, LFO control Data (LFO control D), filter / envelope control data (FEG control D), volume envelope control data (AEG control D),
It is composed of note-on data, other data (others D), and a work area used when the musical tone sample of each sounding channel is generated. The waveform designation D, the LFO control D, and the AEG control D of each tone generation channel are the tone color data PD1, PD2, PD3, ... PD1 described above.
The data is created by processing any one of 6 according to the contents of the MIDI event.

Next, FIG. 5 shows an output buffer. In the tone generating method of the present invention, if the operation cycle is different,
Since the number of musical tone waveform samples that are collectively calculated when the calculation time arrives becomes different, the calculation cycle C
An output buffer is prepared for each C. In case of illustration,
This shows a case where there are three types of operation cycles. As shown in FIGS. 7A to 7C, the basic operation cycle (CC
= 0: Buffer 0 for equivalent sampling frequency 48 kHz, 1/2 operation cycle (CC) of the basic operation cycle
= 1: Buffer 1 for equivalent sampling frequency 24 kHz, 1/4 operation cycle (CC) of the basic operation cycle
= 2: Buffer 2 for equivalent sampling frequency 12 kHz) is prepared. Therefore, as shown in the figure, the buffer 1 has a capacity capable of storing 1/2 the number of samples of the buffer 0, and the buffer 2 has a capacity capable of storing 1/4 of the samples of the buffer 0.

The operation cycle CC is designated for each tone generation channel and for a tone waveform during one tone generation,
As a waveform for one unit interval performed at each calculation time,
The number of musical tone waveform samples arithmetically generated in each tone generation channel is designated, and it can be indicated by an equivalent sampling frequency corresponding to the number of musical tone pronunciation samples generated. The designation of the operation cycle CC is determined according to the frequency band of the musical tone waveform sample to be generated.

That is, the buffer 0 shown in FIG. 5A is for the case where the frequency band of the musical tone waveform is wide, and 128 samples (SD1, SD2, SD3. (SD128) is an output buffer for storing musical tone waveform samples, and the buffer 1 shown in FIG. 7B is for the case where the frequency band of the musical tone waveform is not so wide and is generated every time the operation time arrives. 64 samples (SD1, SD2, SD3 ...
SD64) is used as an output buffer for storing musical tone waveform samples, and the buffer 2 shown in FIG. 7C is for the case where the musical tone waveform frequency band is narrow, and 32 samples are generated every time the operation time arrives. (SD1, SD2, SD
3 ... SD32) is used as an output buffer in which musical tone waveform samples are stored.

The output buffers of these buffers 0 to 2 have the same operation cycle CC (the frequency bands are substantially the same) regardless of the tone generation channel.
Musical tone samples are added and stored across all sound channels. That is, the newly calculated musical tone waveform sample is added to the already stored musical tone waveform sample and stored at the same position in the same output buffer. Further, when the generation of the musical tone waveform samples of all the tone generation channels is completed, the musical tone waveform samples of all the tone generation channels are accumulated and passed to the reproducing unit 9 to be sounded. Since buffer 1 and buffer 2 are different from each other, they cannot be simply accumulated.

Therefore, by interpolating the 64 musical tone waveform samples of the buffer 1, 128 musical tone waveform samples are obtained and stored in the buffer 1'shown in FIG. By interpolating the musical tone waveform samples, 128 musical tone waveform samples are obtained and stored in the buffer 2'shown in FIG. 2 (e). In this case, buffer 1 '
Sound waveform samples SD1, SD2, SD3, ... SD
Every other 128 is SD of musical tone waveform sample of buffer 1
1, SD2, SD3, ... SD64, which is the same as that of the musical sound waveform samples SD1, SD2, SD3 of the buffer 2 ',
..SD128 becomes the same as the musical sound waveform samples SD1, SD2, SD3, ..

In this way, buffer 0, buffer 1 ', and buffer 2', each having 128 samples,
The musical tone waveform samples at the same position of are accumulated and stored in the same position of the buffer 0, for example. And buffer 0
Is reserved for reproduction and is read out from the reproduction unit 9 to be sounded. Note that it is not necessary to store the tone waveform samples of all the sound generation channels in the buffer 0.
Any output buffer having a sample area may be used.

Next, the outline of the musical tone generating method executed in the musical tone generating apparatus shown in FIG. 1 which uses the output buffer as described above will be described with reference to FIGS. 6 to 11.
Here, the musical sound generating apparatus is of a waveform memory sound source system, FIG. 6 shows an example of waveform data during one sound generation, and FIG. 7 shows a frequency spectrum at each time point of the waveform data shown in FIG. FIG. 8 shows an example of the pitch change with respect to the time of the musical tone waveform during one sound generation when the generated musical tone waveform sample is reproduced at a constant reproduction rate, and FIG. 9 shows the musical sound waveform sample during one tone generation. FIG. 10 shows an example of a change mode of the change of the operation cycle with respect to the time of the operation generation, and FIG. 10 shows an example of the change mode of changing the F number with respect to the time of the operation generation of the tone waveform sample during one sound generation. FIG. 11 shows a timing chart in the sound source processing for generating a musical tone waveform.

In the musical tone generating method of the present invention, FIG.
As shown in (a), a musical tone waveform sample for one unit section to be read out from the reproducing unit 9 is arithmetically generated every time the arithmetic time comes. In this case, a new note-on event or note-off event is received between the calculation times as shown in FIG. 9B, and a plurality of musical tone waveform samples corresponding to these events are received. Calculations are collectively generated at the time shown in (c). Then, the musical tone waveform samples for all the sound generation channels, which have been arithmetically generated and stored in the output buffer 0 as described above, are set to 1 in the reproducing section 9 as shown in FIG.
It is read out as a tone waveform sample of a unit section, reproduced at a constant reproduction rate (constant reproduction sampling frequency), and sounded.

According to the present invention, when a plurality of musical tone waveform samples for one unit section are arithmetically generated as described in the explanation of the output buffer, the arithmetic cycle CC according to the frequency band of the musical tone waveform to be arithmetically generated is set. I am trying to change it. Therefore, a mode of changing the operation cycle CC will be described. The waveform data during one sound generation of the attenuated sound system changes, for example, as shown in FIG. 6, but the horizontal axis thereof indicates the time during sound generation and is included in the waveform data at the time points a, b, c, and d. Figure 7 shows the spectral distribution of the fundamental wave and harmonics.
Shown in The portion shown at the time point a is the attack portion, and its musical tone waveform is shown above it, for example, but it has a complicated waveform including many harmonic spectra as shown in FIG. 7A. Next, the part indicated by the time point b is a part where the attenuation is slightly advanced, and as shown in FIG. 7B, the attenuation of the spectrum of the higher harmonic wave is advanced rapidly.

Further, the portion indicated by the time point c is the sustaining portion (sustaining portion) in which the attenuation is further advanced, and its musical tone waveform is shown above it, for example, but as shown in FIG. Attenuated and has a simple waveform close to the fundamental wave. Next, the portion indicated by the time point d is a portion where the attenuation is considerably advanced, and as shown in FIG. 7D, the spectrum of the higher frequency harmonic is almost attenuated to become the fundamental wave. As described above, the waveform data of one sound is generated so that the frequency band of the waveform data is different depending on the time of one sound, and the waveform data of the widest frequency band is fixed to a calculation cycle that can be generated. Then, as described above, the waveform data up to the unnecessary frequency band is calculated and generated.

Therefore, in the tone generating method according to the present invention, as shown in FIG.
As shown in (4), the operation cycle CC is changed according to the lapse of time during which one sound is being produced. In the case shown in the figure, the operation cycle CC is set to 48 kHz which is the frequency of the basic operation cycle until time t2, and is set to 24 kHz corresponding to half the operation cycle up to now from time t2 to time t4.
After time t4, the operation cycle CC is changed to 12 kHz, which corresponds to half the operation cycle. It should be noted that this change of the operation cycle CC is performed by changing the operation shown in FIG.
The 1 unit section shown in (1) is set as the minimum unit and is not changed in the 1 unit section.

As described above, since the operation cycle CC according to the frequency band is used, the present invention does not perform the operation generation of the waveform samples up to the unnecessary frequency band as much as possible, and the useless operation can be reduced. Then, if the reduced calculation is distributed to the calculation of another sound generation channel, the quality of the musical sound of that channel can be improved, and the number of sound generation channels can be increased by the reduced calculation. It is also possible to design so that the operation cycle of each tone generation channel is changed in the middle of one unit section. In that case, depending on the operation cycle CC to be changed,
The generation operation of each channel is changed, and the output buffer for adding the output of the channel is changed in the middle of one unit section.

By the way, the waveform data WD1, WD2, ... WDn stored in the RAM 3 shown in FIG.
As described above, since the frequency band required for recording changes during one sound generation, the sampling frequency for sampling and storing the waveform data is changed according to this change to reduce the amount of stored waveform data. ing. In this case, it is general that the sampling frequency is increased in the attack section, and the sampling frequency is gradually decreased as the waveform data is attenuated. Thus, when the waveform data stored while changing the sampling frequency during one sound is read from the RAM 3 at a constant rate, the pitch of the waveform data changes according to the sampling frequency.

In FIG. 6, the waveform shape for one cycle each of time point a and time point c is shown. The width of the waveform at time point c in the horizontal axis direction is the width of the waveform at time point a in the horizontal axis direction. The reduction of about half is due to the change of the sampling frequency during one sound generation described above. That is, the pitch of the original waveform was almost the same at the time point a and the time point c, but the sampling frequency when recording the waveform was at the time point c.
Since the frequency is about half that at time point a, the length of the address corresponding to one cycle of the waveform stored in the waveform memory is about half the length of the address corresponding to one cycle at time point a at time point c. It has become.

For example, a waveform showing a change in pitch of the original pitch OP which is a pitch when the waveform data is read out one sample at a time in each basic operation cycle (48 kHz in the example shown in FIG. 9) during one sound generation. An example of (OPEG) is as shown in FIG. In this figure, note
An example is shown in which the original pitch OP of the number C2 linearly changes to the pitch of the note number C3 one octave higher from the time t1 to the time t3. (However, the vertical axis is the cent scale.) Therefore, when such a waveform data is read to generate a musical tone sample, the reading speed (= F number =) is set so that the pitch does not change during one sound. It is necessary to control the amount of advance of the read address of the waveform memory for each sample of the generated musical sound. Here, the sampling frequency when the waveform data is sampled and loaded into the waveform memory is just the opposite change (on the cent scale) from the above-mentioned OPEG waveform.
OP that controls the shape of the OPEG waveform based on the data that controls the change in sampling frequency during recording
EG control data is generated.

In order to generate a tone having a specified pitch, a pitch for shifting the original pitch (indicated by the value of the OPEG waveform) to the specified pitch based on the pitch and the OPEG waveform. F as change amount
The number should be generated. As a concrete means, first, the difference between the pitch designated as the sounding pitch and the original pitch is calculated on a cent unit basis. Then, the obtained difference is converted from cent unit to Hz unit to obtain the F number. In this case, even if the instructed sounding pitch does not change, if the OPEG changes with time, the F number becomes OPE.
It changes according to the change of G.

Further, the number of waveform samples indicated by the calculation cycle CC is calculated and generated as the number of waveform samples in one unit section each time the calculation time arrives.
When the operation cycle CC is changed in the middle of one sound generation as shown in, the advance amount (= F number = reading speed) of the waveform data to be read for each sample operation at that time is
It must be changed according to the operation cycle CC. For example, when the basic operation cycle CC of 48 kHz (CC = 0) is halved to 24 kHz (CC = 1), the advance amount for each sample operation is doubled from the initial value, and further, 12 kHz.
If it is reduced to (CC = 2), it is necessary to set the advance amount to be four times the initial amount. Therefore, in the present invention, the F number, which is the amount of advance of each tone waveform sample operation of the address counter that reads out the waveform data specified at the time of operation generation, is also changed at the timing when the operation cycle CC changes. ing. The calculation cycle CC is set for each channel so as to save the wasteful waveform calculation amount of each sound generation channel.

In the present invention, both the waveform compression (change of the OPEG waveform shown in FIG. 8) due to the change of the sampling frequency of the waveform data and the saving of the waveform calculation amount due to the change of the operation cycle CC (change of the CC shown in FIG. 9) are performed. Has been realized,
As a result, the F number changes during one pronunciation as shown in FIG. As shown in this figure, the F number, which was initially FN ₀ , decreases in a curve form from time t1 to time t2 in accordance with the change in the OPEG waveform. Further, at the time t2, the F number is doubled in response to the halving of the operation cycle CC, and from the time t2 to the time t3, in accordance with the change of the OPEG waveform, the F-number is reduced to the curved shape as before. There is.

Next, from time t3 to time t4, a constant value FN ₀ (a doubled OPEG waveform and a halved operation cycle CC cancel each other out and happens to return to the original F number), Operation cycle C at time t4
Corresponding to the fact that C was set to 1/4 of the original, an additional 2
Is doubled, and is a constant value (2FN ₀ ) after time t4
It is said.

The formula for calculating this F number is shown below. F number = 2 ^{(SP-OP) / 1200} * 2 ^{CC where} SP is the pitch of the note number to be pronounced, OP is the original pitch, and CC is the ratio to the basic operation cycle (48 kHz). When the operation cycle is the basic operation cycle, CC = 0, when the operation cycle is 1/2, CC = 1, and when the operation cycle is 1/4, CC = 2.

FIG. 12 is a diagram showing a flow chart of a main routine of the software tone generator to which the musical tone generating method of the present invention is applied, which is executed by the CPU 1. When the main routine is started, initialization is performed in step S10. In the initial setting, all tone generation channels are cleared, and tone color data and waveform data are prepared. Next, in step S20, it is determined whether or not there is received data. This determination is made by MI in the input buffer shown in FIG.
This is performed by determining whether DI received data is recorded. Then, if there is no MIDI reception data in the input buffer, the process directly proceeds to step S40, but if there is reception data in the input buffer, a process (note-on process, note-off process) corresponding to the MIDI event received in step S30. Processing, etc.) and other processing are performed.

Then, in step S40, the switch (S
It is determined whether or not (W) is operated, and if the switch is not operated, the process directly proceeds to step S60.
When the switch is operated, it is determined that there is a SW event, and the processing for setting the tone color of each part of the plurality of parts in accordance with the operated panel switch is performed in step S50.
The panel SW event process is performed. Subsequently, in step S60, a sound source process for collectively calculating and generating musical tone waveform samples is performed every time the calculation time arrives, other processes are performed in step S70, and the process returns to step S20 and steps S20 to S20. S70
The above process is repeated and repeated (steady loop). If the reproducing unit 9 is a dedicated sound source capable of selecting an algorithm or a DSP sound source, the sound source processing in step S60 is unnecessary.

Next, FIG. 13 shows a flowchart of the MIDI reception interrupt processing executed by the CPU 1. This process
The MIDI interface 5 is some external MIDI
It is activated by an interrupt when an event is received. This M
The IDI reception interrupt process is a process performed with priority over other processes. When this MIDI reception interrupt process is started, the reception data received by the MIDI interface 5 is fetched in step S80, and step S9
At 0, the received data is paired with the time data at the time of reception, is written in the input buffer described above in the format shown in FIG. 3, and is returned to the processing when the interrupt occurs. As a result, the received MIDI data is sequentially
It will be written in the input buffer together with the reception time.

Next, FIG. 1 is a flowchart of the tone color selection event process of Part 1 as an example of the panel switch event process performed in step S50 of the main routine.
4 shows. When the tone color selection event process of Part 1 is started, the tone color number selected by the panel switch is stored as t1 in the register in step S100, and this process ends. As a result, the tone color of part 1 is determined, and a process of selecting tone colors of all parts (not shown) is performed in step S50 of the main routine.

FIG. 15A is a detailed flowchart of the note-on event process and the note-off event process performed in the received data process executed as step S30 in the steady loop of the main routine.
(B). If the received data is a note-on event, the note-on event processing shown in FIG. 15A is started, and in step S110, the note number of the note-on event in the input buffer is NN and the velocity is VEL. As a result, the tone color for each part is loaded into the register as t, and the occurrence time of the note-on event is loaded into the register as TM. Next, in step S120, the tone number allocation processing of the note number NN stored in the register is performed, and the number i of the allocated channel (ch) is stored in the register.

Further, in step S130, the tone color data TP (t) of the tone color t set for each part is processed according to the note number NN and velocity VEL. The tone color data in this case is the tone color data P shown in FIG.
It is any tone color data selected from D1 to PD16. Then, in step S140, the tone color data processed by the process of the step including the pitch SP to be sounded is stored in the tone generator register of the channel number i fetched in the register shown in FIG. Write with the event occurrence time TM. Here, the waveform designation data D written in the tone generator register is
As a waveform to be obtained by referring to the tone range waveform designation data in the tone color data shown in FIG. 2 with a note number NN, and to be used for tone generation corresponding to the note number NN,
Any one of the waveform data WD1 to the waveform data WDn is designated.

Next, in step S150, operation cycle control data designating the timing for changing the operation cycle of the ich fetched in the register and the operation cycle value to be changed is set in the ich area of the tone generator register. The calculation cycle control data is set based on the calculation cycle control data stored in the tone color data selected by ich. Since the timing for changing the operation cycle is designated with the minimum unit being one unit interval in which the operation is performed at each operation time described above, the timing can be detected and executed by the number of times the operation time is reached. Next, in step S160, the OPEG control data read from the waveform data area is set to the ich area of the tone generator register. This OPEG control data is an OPEG showing the state of change of the original pitch during one sound generation as shown in FIG.
This is data for controlling the shape of the waveform. Next, in step S170, note-on is written in the tone generator register of ich fetched in the register, and the note-on event process ends.

The note-off process of the flowchart shown in FIG. 15B is started when the received data is a note-off event, and in step S180, the note-off number of the note-off event in the input buffer is NN.
As a result, the tone color for each part is loaded into the register as t, and the occurrence time of the note-off event is loaded into the register as TM. Then, step S190.
At, the tone generation channel (ch) produced with the tone color t and the note number NN is searched, and the number i of the found tone generation channel is stored in the register. Next, step S2
At 00, the occurrence time TM and the note-off taken in by the ich sound source register are written, and the note-off process ends.

Next, a detailed flowchart of the sound source processing executed as step S60 in the steady loop of the main routine will be described with reference to FIG. When the sound source processing is started, the sound source register is checked in step S210, and if there is no new writing, the process directly proceeds from step S220 to step S250, but it is determined in step S220 that new writing has been performed. If so, the data written in step S230 is converted into control data for controlling the waveform calculation.
Next, the converted control data is prepared in step S240. Here, the tone generator based on the converted data such as note-on / off, pitch bend, EXP, and pan based on the converted data. Preparations for control and creation of a set of control time / control data are performed. That is, every time writing is performed in step S230 and step S240, preparation for calculation for musical tone generation steps S270 to S290 to be executed later is performed.

In the following step S250, arithmetic time management is performed to specify a timing earlier than the time when the waveform data being reproduced ends by a predetermined time so that the reading of the reproduced waveform data by the reproducing unit 9 is not interrupted. That is, as shown in FIG. 11, when the calculation time shown in FIG. 11A is reached, calculation generation of a plurality of tone waveform samples corresponding to one unit section is executed as shown in FIG. The musical tone waveform sample thus generated is read and reproduced by the reproducing unit 9 as a musical tone waveform of one unit section as shown in FIG. 7D, but the waveform sample read by the reproducing unit 9 is not interrupted. In consideration of the time required for the operation generation shown in FIG. 11C, the operation time management is performed so as to set the operation time shown in FIG.

Next, in step S260, it is determined whether or not the calculation time at which the calculation time management has been performed has been reached. If the calculation time has not been reached, the sound source processing ends immediately. Then, if there is no new writing in the sound source register and the operation time has not been reached, the sound source processing exits without performing any processing, but if the steady loop circulates several times, the operation time is reached, and In S270 and thereafter, the calculation and generation process of the musical tone waveform sample corresponding to one unit section is performed. That is, step S270
Calculation cycle C for specifying the number of musical tone waveform samples to be calculated and generated here according to the musical sound generated by each channel
C change processing, operation order determination processing that determines the operation order of each channel so that operations are performed in order of the channels in which important musical tones are generated, and even if the operation cycle CC is changed, the tone waveform samples of all sound generation channels are sampled. If it cannot be generated, the mute ch process is performed to determine the channel to mute from the end of the calculation order.

Then, a control data expansion process is executed in step S280 to expand the data on which the sound source control is prepared in step S240 on the time axis to prepare for calculation, and further the data expanded in step S290. Based on the above, the waveform calculation for calculating the reproduced waveform data (tone waveform sample) for one unit section is executed. Further, as described with reference to FIG. 5, the reproduced waveform data having different operation cycles are interpolated to have the same number of samples as the number of samples generated in the basic operation cycle, and the same number of samples are set to all the sound generation channels. The reproduced waveform data of is accumulated and stored in the buffer 0, for example. Then, a reproduction reservation process is performed to reserve the reproduction waveform data created in step S300 so that the reproduction unit 9 reads the reproduction waveform data. Here, the reproduction reservation is a reproduction waveform obtained by accumulating the reproduction waveform data of all sound generation channels. This is performed for buffer 0 in which data is stored.

According to the present invention, the operation cycle can be changed for each tone generation channel and the operation cycle can be changed in the middle of one tone generation of each tone generation channel. FIG. 17 is a detailed flowchart of the channel control process executed in step S270 in the sound source process described above, in which the process of changing the channel is performed. When the channel control process is started, a control process for changing the operation cycle during one sound generation based on the operation cycle control data of each channel is performed in step S310. Here, the time is counted and the timing of changing the operation cycle is managed. And as a result of management,
If there is no channel for which the operation cycle is changed at this time, the process directly proceeds to step S340. However, if there is a channel for which the operation cycle is changed (when the change timing designated by the operation cycle control data of the channel is reached). Is determined to be present in step S320, and the operation cycle CC of the channel is determined to be in step S320.
At 330, a new value (changed value at the same timing designated by the same operation cycle control data) is changed.

Next, in step S340, the process of determining the calculation order of the sound generation channels is performed. Here, as described above, the calculation of the channels producing the important sound or the sound that is difficult to be muted is given priority. The calculation order of the channels is determined so that the calculation is performed. Here, since the tone generation channel for which a musical tone is not being generated is not calculated, it need not be included in the calculation order. And step S
At 350, the calculation amount of each sound generation channel is accumulated to calculate the total calculation amount. In this case, the calculation amount of each sounding channel depends on the calculation cycle of each sounding channel.
Also, if the pronunciation method is different for each channel,
It will be different depending on it. Next, it is determined whether or not the total amount of calculation calculated in step S360 is too large. However, if the total amount of calculation calculated is within the predetermined range, the channel control process is terminated and the waveform calculation is completed. Processing is performed.

Further, if it is determined that the calculation is not completed by the timing when the reproducing unit 9 reads out and the reproduced waveform data is interrupted if the total calculation amount calculated in step S360 is too large and the total calculation is performed as it is. Is step S370.
At "1", the necessary number of operation cycles CC of the tone generation channels which have been calculated after the predetermined order of operation are added. That is, the number of samples generated by reducing the operation cycle CC (CC = 1 for CC = 0 channel and CC = 1 for CC = 1 channel) is reduced. As a result, it is determined in step S380 whether the total amount of calculation is within the predetermined range.
If it is determined that the channel number is within the predetermined range, the channel control process ends, but if it is determined that the channel number is still beyond the predetermined range, the channel control process is started from the last channel in step S390. The muffling channel is sequentially determined, and the muffling process is executed.

In the conventional sound source control, when there are too many tones to be sounded, a truncation process, that is, a process of muting one of the tones being sounded is performed. In the present embodiment, even if it is determined to be "YES" in step S360, in the processing of steps S370 to S390, first, the calculation cycle is reduced to avoid the conventional muting of musical tones. Moreover, in this case, it is the less important sound that is reduced in the calculation cycle, so the influence on the music is small. Further, in the present embodiment, when it is not possible to deal with the problem only by reducing the calculation cycle, the muffling process similar to the conventional one is executed. This completes the channel control process, and the waveform calculation process continues.

Next, a detailed flow chart of the waveform calculation process is shown in FIG. 18 and will be described. When the waveform calculation process is started, the sounding channel of the calculation order 1 is prepared in step S400. In this case, all the output buffers shown in FIG. 5 are cleared before the calculation. Then, in step S410, based on the pitch SP, the operation cycle CC, and the original pitch OP, the expression 1 described above is used.
Generates an F number. Since the F number of each channel is calculated each time in this step S410, the F number changes immediately according to the change of the calculation cycle CC or the original pitch OP during the sound generation. In addition, the pronunciation pitch SP during the pronunciation by the effect such as pitch bend and vibrato.
It is also possible to change the F number according to the change of.
In addition, since the time interval at which the calculation time occurs is generally about several milliseconds, the F
It is not necessary to change the number.

Next, in step S420, a read address is created, waveform data is read based on the integer part of the created read address, and interpolation processing between consecutive waveform data is performed based on the decimal part of the read address. . In the process of step S420, the process from the read address creation for each interpolation sample to the interpolation process as one unit is repeated a number of times according to the operation cycle CC. As a result, the number of interpolation samples corresponding to the operation cycle CC is generated. In addition,
The read address of each interpolation sample is obtained by adding the F number to the read address of the immediately preceding interpolation sample. Therefore, the read address advances at a speed corresponding to the F number for each interpolation sample, and the pitch of the read waveform is controlled according to the moving speed.

Further, in step S430, after the volume control by the volume EG waveform is performed on the interpolation sample generated in the previous step, it is added to any one of buffer 0 or buffer 2 of the output buffer according to the operation cycle CC. Be done. This volume EG waveform is a waveform that controls the change in the volume envelope from the rise of the musical sound to the attenuation,
AEG control D set in the register of each sound channel
Is calculated and generated in correspondence with each interpolation sample. As described above, the number of interpolation samples to be generated and the number of samples stored in the selected output buffer are both controlled by the operation cycle CC of each tone generation channel and are equal to each other. Therefore, step S430
The process (1) is also performed for each sample as in step S430. That is, for the generated interpolation sample,
Volume control by volume EG waveform and calculation cycle CC
The addition to the corresponding sequential position of the output buffer according to is sequentially performed for each sample. By executing each process in the above procedure, the number of times of writing / reading of the arithmetic register of the CPU 1 is minimized, and the overall processing speed is improved.

In this way, as shown in FIG. 5, the musical tone sample calculated in the tone generation channel of the basic calculation cycle is stored in the buffer 0, and the tone generation channel of the calculation cycle of 1/2 of the basic calculation cycle is stored in the buffer 1. The tone sample calculated in step 1 is stored in the buffer 2 in 1 of the basic calculation cycle.
The tone samples calculated in the tone generation channel of the / 4 calculation cycle are sequentially added to the data values stored up to that point and stored respectively. In this case, the interpolation sample calculated first is used. Therefore, it is stored as it is in the output buffer corresponding to the operation cycle CC of that channel.

Next, in step S440, it is determined whether or not the calculation of all the tone generation channels to be calculated has been completed. If there are any tone generation channels to be calculated (while sounding), the process ends. If it is determined that the sounding channel has not been played, the flow proceeds to step S480, the preparation of the tone generation channel of the second order is performed, and the flow returns to step S410. Then, the loop processing of steps S410 to S480 is performed until the calculation of all the sound generation channels is completed. If the CPU 1 is executing software other than the program of the present invention in parallel, it takes time to process the software,
This calculation may be delayed, but in that case, it may be determined in step S440 that the reproduction has been completed even if there is a channel that has not been calculated so that the reproduction of the reproducing unit 9 is not interrupted.

As a result, the interpolation samples of a plurality of channels stored in the buffer 0, the buffer 1, and the buffer 2 shown in FIG. 5 according to the operation cycle CC are accumulated and stored. When the calculation of all the sound generation channels is completed, the interpolation processing (double oversampling) of the waveform samples stored in the buffer 1 is performed in step S450, and the number of samples calculated in the basic calculation cycle (in this case, The number of samples is the same as that of the buffer 0, and is stored in the buffer 1 ′ having the same configuration as the buffer 0. (See FIG. 5D) Next, step S46.
At 0, the interpolation processing (4 times oversampling) of the waveform samples stored in the buffer 2 is performed, and the number of samples is the same as the number of samples when the calculation is performed in the basic calculation cycle. 2 '(see FIG. 5 (e)).

Subsequently, in step S470, the buffer 0
By adding the waveform samples of the buffer 1'and the buffer 2'to the waveform sample, the waveform samples obtained by accumulating the waveform samples of all the sound generation channels are realized on the buffer 0 (FIG. 5).
(See (f)). As a result, the waveform calculation process ends, and the waveform sample on the buffer 0 is reserved and read by the reproducing unit 9 to be sounded.

In the above, the tone generation method of the present invention has been described as a program executed by the tone generation device shown in FIG. In addition, the tone generation method of the present invention,
It may be executed as one application program on a general-purpose computer running Windows (Microsoft OS for personal computers) or other operating systems.

[0066]

Since the present invention is configured as described above, the waveform calculation cycle is determined for each sounding channel depending on whether or not the musical tone waveform to be sounded has a wide band or according to the degree of importance. Therefore, regardless of the wide band or narrow band of the tone waveform, the tone waveform sample can be calculated and generated without performing unnecessary waveform calculation. Further, in the case of the attenuated sound system, the attack section during one sound is generated to generate many waveform samples by increasing the waveform operation cycle, and the sustain section is decreased in the waveform operation cycle to generate waveform samples. It is possible to efficiently generate a waveform sample during one sound generation, while performing no waveform calculation.

As described above, since it is possible to save the waveform calculation in a specific tone generation channel, if the amount of waveform calculation of the tone waveform of the other channels is increased, the tone quality of that channel can be improved, and The number of sound generation channels can be increased by the saved waveform calculation amount. Furthermore, independently for each pronunciation channel,
Since it is possible to control the number of generated musical tone samples per unit time, it has become possible to set the quality difference of generated musical tones between sounding channels. In addition, it is possible to reduce the calculation amount of the sound generation channel that is less affected even if the quality is low.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a musical tone generating apparatus that executes a musical tone generating method of the present invention.

FIG. 2 is a diagram showing tone color data and waveform data areas on a RAM of the present invention.

FIG. 3 is a diagram showing an input buffer area on a RAM of the present invention.

FIG. 4 is a diagram showing a sound source register area on a RAM of the present invention.

FIG. 5 is a diagram for explaining an output buffer area on the RAM of the present invention and its operation.

FIG. 6 is a diagram showing an example of waveform data during one sound generation.

FIG. 7 is a diagram showing a spectral distribution of waveform data during one sound generation.

FIG. 8 is a diagram showing an example of a waveform of OPEG during one pronunciation.

FIG. 9 is a diagram showing an example of changes in a calculation cycle during one sound generation of the musical sound generating method of the present invention.

FIG. 10 is a diagram showing an example of changes in the F number during one sound generation of the musical sound generating method of the present invention.

FIG. 11 is a diagram showing a timing chart of a sound source process of the musical sound generating method of the invention.

FIG. 12 is a diagram showing a flowchart of a main routine of the musical sound generating method of the present invention.

FIG. 13 is a diagram showing a flowchart of MIDI reception interrupt processing of the musical sound generating method of the present invention.

FIG. 14 is a diagram showing a flowchart of a tone color selection event process of Part 1 of the musical tone generating method of the invention.

FIG. 15 is a diagram showing a flowchart of note-on event processing and note-off event processing in the received data processing of the musical sound generating method of the present invention.

FIG. 16 is a diagram showing a flowchart of a sound source process in the main routine of the musical sound generating method of the invention.

FIG. 17 is a diagram showing a flowchart of channel control processing in sound source processing of the musical sound generating method of the present invention.

FIG. 18 is a view showing a flowchart of waveform calculation processing in the sound source processing of the musical sound generating method of the invention.

[Explanation of symbols]

1 CPU, 2 ROM, 3 RAM, 4 timer, 5
MIDI interface, 6 keyboard, 7 display, 8 hard disk, 9 playback unit, 10
DAC, 11 sound system

Claims (8)

[Claims] 1. A musical tone generating method for generating a musical tone waveform sample by waveform computation of an arithmetic processing device, wherein a waveform computation cycle of the waveform computation is characterized in that a waveform characteristic of each tone generation channel of the musical tone waveform sample to be generated and each tone generation are performed. A tone generation method characterized in that each tone generation channel is determined according to the importance of the channel. 2. A musical tone generating method for generating a musical tone waveform sample by waveform calculation of a calculation processing device, comprising: generating a musical tone waveform sample during one sounding in accordance with a content ratio of harmonics that changes with time in the musical tone waveform sample during one sounding. A musical tone generating method characterized in that the waveform calculation cycle of the waveform calculation is changed in the middle. 3. A tone generation method including the following steps (1) to (4) for performing tone generation calculation for a plurality of tone generation channels and generating waveform data of a plurality of tone sounds corresponding to the plurality of tone generation channels. (1) A tone control step of generating first control data for instructing, for each tone generation channel, the characteristics of the tone generated by the plurality of tone generation channels. (2) The number of samples of tone generated per unit time,
Arithmetic control step for generating second control data instructing each tone generation channel (3) For the plurality of tone generation channels, waveform data of musical tones corresponding to each tone generation channel is set according to the tone characteristic instructed by the first control data. And a step of generating a sound based on the waveform data of a plurality of channels generated in the step of generating a musical tone, which is calculated and generated at the sample generation speed indicated by the second control data. 4. The calculation control step corresponds to a musical tone characteristic of waveform data generated in each tone generation channel,
4. The musical sound generating method according to claim 3, wherein the second control data is generated. 5. The musical tone according to claim 3, wherein the calculation step changes the generated second control data in response to the time variation of the musical tone characteristic of the waveform data generated in each tone generation channel. Method of occurrence. 6. The first control data includes pitch information designating a pitch of a musical sound to be generated in each sound generation channel, and in the musical sound generating step, a sample generation speed instructed by the second control data. 4. The musical tone generating method according to claim 3, wherein the pitch information of each tone generation channel is converted into a phase change speed of a musical tone to be generated in accordance with the above. 7. A musical tone generating method including the following steps (1) to (5) for simultaneously generating at least two musical tones. (1) A first generation step of generating a first musical tone waveform sample containing many high frequency components at a generation rate of N samples per unit time. (2) A second musical tone waveform sample having few high frequency components is measured per unit time. Second generation step of generating at a generation rate of M samples (where M <N) (3) Interpolating the second musical tone waveform of the M samples to obtain N
Conversion step of converting to a second musical tone waveform of the sample (4) Mixing step of sequentially adding the first musical tone waveform of the N samples and the second musical tone waveform of the N samples to obtain a mixed musical tone waveform of N samples (5) A step of generating a sound based on the mixed tone waveform obtained in the mixing step 8. A tone generation method including the following steps (1) to (6), wherein tone generation operation is performed on a plurality of tone generation channels to generate waveform data of a plurality of tone sounds corresponding to the plurality of tone generation channels. (1) Dividing step of grouping the plurality of sound generation channels into a first group and a second group (2) For each sound generation channel of the first group, generate N tone sound waveforms for each unit time, A first generation step of sequentially adding N channels and outputting a first mixed waveform of N samples (3) For each sound channel of the second group, a musical tone waveform of M (M <N) samples per unit time Produces
Second addition for M samples by sequentially adding over multiple channels
Second generation step of outputting mixed waveform (4) Interpolating the second mixed waveform of the M samples to obtain N
Converting step of converting into a second mixed waveform of samples (5) Mixing step of sequentially adding the first mixed waveform of N samples and the second mixed waveform of N samples for each sample to obtain a mixed tone waveform of N samples (6) Step of generating sound based on the mixed tone waveform obtained in the mixing step