JP2002297138A - Musical sound generating device and program for musical sound generation and processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give no musically unnatural influence even when assignment processing for securing a sound generation channel is performed by forcibly muting a musical sound signal in sound generation. SOLUTION: When eight sound generation channels of a sound source LSI 8 are all in sound generation and MIDI data of a new sound generation event are inputted through a MIDI interface 7, a CPU 1 calculates the priority of the sound generation event according to the kind of control data giving musical effect and the respective sound generation parts and assigns the new sound generation event by forcibly muting the sound generation event of a sound generation channel when the priority of the new sound generation event is higher than the lowest priority of the sound generation event in the sound generation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical sound generating device and a musical sound generating program.

[0002]

2. Description of the Related Art In recent years, musical tone generating apparatuses such as electronic musical instruments have a configuration in which a plurality of tone generating events can be simultaneously generated to provide rich musical tones. For this purpose, a sounding means such as a sound source has a predetermined number of sounding channels (also referred to as "voices"), and assigns sounding events to each sounding channel by an assigner or the like. MIDI
When a sound generation event occurs due to data input, performance, or the like, if a predetermined number of sound channels are all sounding, one of the sound events is first dumped to forcibly mute the sound, and the sound channel is forcibly muted. (Also referred to as a “truncation process”), that is, an assignment process that gives priority to late arrival. In this assignment process, it is necessary to select a sound generation channel to be muted under some conditions. Conventionally, the following 3
There were two selection methods. The first method is to select the tone signal having the most advanced envelope of the tone signal being emitted. The second method selects the tone signal having the lowest envelope level. A third method is to select the MIDI data or performance that has been received, for example, the oldest key.

[0003]

However, in the above-mentioned prior art, since the method of selecting the sounding channel to be silenced does not take into account musical elements, the sound generated depending on the result of the forced silence is reduced. There was a problem of having an unnatural effect. For example, if the sound source of the main melody such as the melody part and the sound part of the accompaniment such as the rhythm part and chord part are sounding simultaneously by the same sound source means, it is impossible to mute the sound part of the main melody by the conventional selection method Not musically desirable. Or, for example,
If the performer intentionally changes the timbre by adding aftertouch to the keyboard, silencing the sounding event will ignore the performer's intention and is not musically desirable. . It is an object of the present invention to prevent musically unnatural effects even when an assignment process for securing a sounding channel by forcibly silencing a sounding event during sounding is performed.

[0004]

According to a first aspect of the present invention, there is provided a musical sound generating apparatus for generating a plurality of sounding parts by a predetermined number of sounding channels.
Setting means (in this embodiment, a priority coefficient is set according to the type of control data for adding a musical effect to the sounding event assigned to each sounding channel of the sound source LSI 8 and the sounding part). CP in FIG.
U1), and when a new sounding event occurs when all of the predetermined number of sounding channels are sounding, the priority for the sounding event being sounded and the new sounding event in each sounding channel is set to the priority. Calculation means for calculating based on the coefficient (in the embodiment, FIG.
And a determining unit (in the embodiment) for determining whether the lowest priority among the priorities of the respective sound channels calculated by the calculating unit is lower than the priority of the new sound event. Is the CPU 1 in FIG.
), When the determination unit determines that the lowest priority is lower than the priority of the new sounding event, the sounding event of the lowest priority is forcibly muted and a new sounding channel is assigned to the sounding channel. An assignment unit (corresponding to the CPU 1 in FIG. 1 in the embodiment) for assigning a sounding event is provided.

According to a seventh aspect of the present invention, there is provided a musical tone generating program executed by a computer of the musical tone generating apparatus (corresponding to the CPU 1 in FIG. 1 in the embodiment). Setting a priority coefficient in accordance with the type of control data for adding a musical effect to a sound event assigned to each sound channel of the sound means of the sound means for sharing a plurality of sound parts by the sound channels of each sound part and each sound part. Calculating a priority of a sounding event being sounded in each sounding channel based on a priority coefficient when a new sounding event occurs when all of the predetermined number of sounding channels are sounding; The lowest priority among the priorities of each sounding channel calculated by the A step of determining whether or not the priority is lower than the priority of the sounding event, and forcing the lowest priority sounding event when the determining step determines that the lowest priority is lower than the priority of the new sounding event. And silencing the sound, and assigning the new sounding event to the sounding channel.

According to the first or seventh aspect of the invention, when a plurality of sounding parts are shared by a predetermined number of sounding channels, a musical effect is added to a sounding event assigned to each sounding channel. The priority is calculated according to the type of control data to be performed and each sounding part, and when a new sounding event occurs when all sounding channels are sounding, the priority of the new sounding event is sounding. If the sounding event of the sounding channel is higher than the lowest priority, the sounding event of the sounding channel is forcibly muted and a new sounding event is assigned.

According to a fifth aspect of the present invention, there is provided a musical sound generating apparatus for generating a sounding event assigned to each sounding channel of sounding means having a predetermined number of sounding channels (corresponding to the tone generator LSI in FIG. 1 in the embodiment). A setting means (corresponding to the CPU 1 in FIG. 1 in the embodiment) for setting the priority coefficient in accordance with the type of control data for giving a tone change, and a new setting when all of a predetermined number of sounding channels are sounding. Calculating means for calculating a priority for a sounding event being sounded in each sounding channel based on a priority coefficient when the sounding event occurs (corresponding to the CPU 1 in FIG. 1 in the embodiment); It is determined whether the lowest priority among the priorities of the respective sound channels calculated by the above is lower than the priority of the new sound event. The determining means (corresponding to the CPU 1 in FIG. 1 in the embodiment) and the sounding event having the lowest priority when the lowest priority is determined to be lower than the priority of the new sounding event. An assigning means (corresponding to the CPU 1 in FIG. 1 in the embodiment) for forcibly silencing the sound and assigning a new sounding event to the sounding channel is configured.

[0010] The program for the tone generation processing according to claim 11 is a program for the tone generation processing executed by a computer (corresponding to the CPU 1 in FIG. 1 in the embodiment) of the tone generator, and Setting a priority coefficient in accordance with a type of control data for giving a timbre change to a sounding event assigned to each sounding channel of a sounding means having a sounding channel of Calculating a priority for a sounding event being sounded in each sounding channel based on a priority coefficient when a sounding event to be newly sounded occurs, and each sounding channel calculated by the calculating step Whether the lowest priority among the priorities of the new is lower than the priority of the new sound event And if the lowest priority is determined to be lower than the priority of the new sounding event by this determining step, the sounding event of the lowest priority is forcibly muted and a new sounding channel is assigned to the sounding channel. Assigning a proper sounding event.

According to the fifth or eleventh aspect of the present invention, when sounding events are assigned to each sounding channel of the sounding means having a predetermined number of sounding channels, the sounding event assigned to each sounding channel is The priority is calculated according to the type of control data that gives a tone change, and when a new sound event occurs when all sound channels are sounding, the priority of the new sound event is set to When the priority is higher than the lowest priority among the sounding events, the sounding event of the sounding channel is forcibly muted and a new sounding event is assigned.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of a tone generator according to the present invention.
In the figure, a CPU 1 has a ROM via a system bus 2.
3, RAM 4, keyboard 5, switch 6, MIDI I /
It is connected to an F (interface) 7. CPU1
Constitutes a computer that executes a musical tone generation program stored in the ROM 3 on the RAM 4 as a work area.

The keyboard 5 inputs musical sound data, which is a sounding event in response to a performance. The switch unit 6 includes switches for setting tone colors, switches for setting performance modes such as keyboard performance and automatic performance, and switches for adding musical effects such as pitch bend and vibrato. MIDI
The I / F 7 exchanges MIDI data, such as sounding events, between an external MIDI device and the electronic musical instrument. The CPU 1 is also connected to the tone generator LSI 8 and outputs pitch data and control data of tone generation events from the keyboard 5 and the MIDI I / F 7 to the tone generator LSI 8.

The sound source LSI 8 has eight sounding channels (hereinafter simply referred to as channels) consisting of CH0 to CH7.
And it is possible to simultaneously generate musical tones corresponding to eight sounding events. The tone generator LSI 8 includes a synthesizer that synthesizes tone signals from eight channels into, for example, two-channel stereo tone signals. And
The synthesized tone signal output from the sound source LSI 8 is converted into an analog signal by the A / D 9, subjected to a filtering process and an amplification process in the output circuit 10, and is output from an external speaker.

FIG. 2 shows a part of the area of the RAM 4, which includes areas for timbre parameters, device total parameters, sounding part parameters, and channel priorities. Although not shown in the figure, the RAM 4 is provided with various registers, and temporarily stores various data in the tone generation processing executed by the CPU 1. As shown in FIG. 3, in the area of the timbre parameters, priority weights, that is, data of the precedence coefficients are stored for each timbre in correspondence with the variable name corresponding to the type of the factor (sound effect added element). You. Even with the same factor, the weight of the priority differs for each timbre.

Factor types include pitch bend that continuously raises and lowers the pitch, vibrato that vibrates the sound, portamento that smoothly transitions from the current pitch to the next pitch, and MIDI touch by keyboard aftertouch operations. There is a mono-pressure for changing the tone color and volume, a poly-pressure for changing the tone color and volume for each sounding channel (voice), a velocity which is a sound intensity, and a touch sense indicating the sensitivity of the velocity.

As shown in FIG. 4, priority weight data is stored in the area of the equipment total parameter corresponding to the variable name corresponding to the type of the factor in the function of the equipment, ie, the tone generator of FIG. You. As shown in FIG. 5, in the area of the pronunciation part parameters, priority weight data is stored for each pronunciation part specified for each MIDI channel in correspondence with a variable name corresponding to the type of factor. . Note that a tone color is specified for each part.

As shown in FIG. 6, priority data is stored in the channel priority area in correspondence with the tone color number assigned to the channel number. As shown in the figure, in this case, two parts, part 0 and part 1, are assigned to eight channels, four channels each. The priority is calculated by a calculation process described later.

Next, the tone generation processing in the tone generator of FIG. 1 will be described. FIG. 1 is a main flowchart showing the operation of the tone generation process of the CPU 1. First, after a predetermined initialization (step A1), a switch process is performed.
(Step A2), keyboard processing (Step A3), MIDI processing (Step A4), assignment processing (Step A5), sound generation processing (Step A6), and other processing (Step A7) are repeatedly executed. The assignment processing in step A5 and the sound generation processing in step A6 are performed by the CPU 1 and the sound source LSI 8
, But are distinguished as two processes for convenience of explanation.

FIG. 8 is a flowchart of the switching process in step A2 in FIG. The mode switch of the switch section is searched (step B1) to determine whether or not the current mode is the automatic performance mode (step B2). If the automatic performance mode is set, the input setting of MIDI data input via the MIDI I / F 7 is performed (step B3). When the mode is not the automatic performance mode but the manual performance mode, the input setting of the performance data input by operating the keyboard 5 is performed (step B4). Step B
After setting 3 or B4, another switch search process is performed (step B5), and the process returns to the main flow in FIG.

FIG. 9 shows step A in the main flow.
4 is a flowchart of the MIDI processing of FIG. It is determined whether or not a MIDI event has been received (step C1). If no MIDI event has been received, this flow ends. If it has been received, it is determined whether or not the MIDI channel matches the part number (step C2). . If they do not match, this flow ends. If they match, the matching part number of the MIDI data is set in the register p (step C).
3).

Next, it is determined whether or not control data for adding a sound effect is included in the received MIDI event (sound generation event). If the control data is included, the received control data is converted to a part number [ p] in the area of the RAM. That is, it is determined whether or not pitch bend has been received (step C4). PB
The received value is stored in [p] (step C5). It is determined whether or not vibrato has been received (step C6). The received value is stored in VB [p] (step C7). It is determined whether or not a monopressure has been received (step C8). The received value is stored in MP [p] (step C9). It is determined whether or not portamento has been received (step C10).
The received value is stored in PM [p] (step C11).
It is determined whether or not a change in touch sense has been received (step C12). The received value is stored in TS [p] (step C13). Then, the priority is recalculated based on the value of the stored control data (step C14).

FIG. 10 is a flowchart of the priority recalculation. The value of the pitch bend priority is calculated by the following equation 1 and stored in the register PB (step D1). The vibrato priority value is calculated by Equation 2 and the
B (step D2). The priority value of the portamento is calculated by Expression 3 and stored in the register PM (Step D3). The value of the priority of the monopressure is calculated by Expression 4 and stored in the register MP (step D).
4). Based on the received monopressure value, the priority value of the polypressure is calculated by Expression 5 and stored in the register PP (step D5). The value of the velocity priority is calculated by Expression 6, and is stored in the register VL (step D6). The value of the priority of the touch sense is expressed by Expression 7
And store it in the register TS (step D
7).

[0022]

(Equation 1)

(Equation 2)

[Equation 3]

(Equation 4)

(Equation 5)

(Equation 6)

(Equation 7)

(Equation 8)

Then, based on the priority value of each register, an average value of the overall channel priority is calculated by the following equation 8 and stored in the register SS (step D).
8). The value of the priority stored in the SS is the RA shown in FIG.
In the area of M, each channel number (voice number)
Is stored for the tone color number corresponding to the priority value together with the velocity and polypressure values. In this case, there are two types of timbres, timbre 0 and timbre 1.

(Equation 8)

FIG. 11 shows step A in the main flow.
5 is a flow of an assignment process of No. 5. First, the assignment processing variables are initialized. That is, 255 (maximum value) is set in the register PL for setting the lowest priority currently found, and 0 (channel number 0) is set in the register CC for setting the channel number under investigation. Set 0 to the register CL that sets the lowest priority channel number found
(Step E1).

Next, the priority of the current channel is set in the register P for setting the priority of the channel under investigation (step E2). At first, the value of the channel number CC under investigation is 0. Next, it is determined whether or not the value of P is 0 (step E3). That is, it is determined whether the priority of the channel under investigation is 0 and the channel is in the mute state. In this case, P
, Ie, 0, and the value of CC, ie, the channel number under investigation, is set in CL (step E).
4).

If the value of P is not 0 at step E3, it is determined whether or not the value of P is smaller than the value of PL.
(Step E5). That is, it is determined whether or not the priority of the currently investigated channel is lower than the lowest priority currently found. If the value of P is smaller than the value of PL, the value of P is set in PL and the channel number of CC is set in CL (step E6). That is, the currently investigated channel is replaced as the currently found lowest priority channel number.

After this replacement, or if the value of P is equal to or greater than the value of PL in step E5, the value of CC is incremented (step E7), and the next channel number is designated. Then, it is determined whether or not the incremented CC value is smaller than 8, that is, whether or not it is equal to or less than the maximum channel number 7 (step E8). If the value of CC is smaller than 8, the next channel number exists,
The process proceeds to step E2 and the above process is repeated.

For example, in the example of FIG. 6, in step E2, the tone P of channel number 0 and the priority of 50 are assigned to P in step E2.
Is set to P, the value of P is not 0 in step E3, so that the process proceeds to step E5. In step E5, P
Is smaller than PL value 255, so that step E
The process proceeds to step 6, where the priority 50 is set in PL, and the channel number 0 is set in CL. Next, at step E7, the next channel number 1 is set, and the routine goes to step E2.

Next, in step E2, the tone color 1 of the channel number 1 and the priority 42 are set in P. Then, the process proceeds to step E3 and step E5. Step E5
Since the value 42 of P is smaller than the value 50 of PL,
The found lowest priority channel numbers are exchanged, and the process proceeds to step E6 where the priority 42 is set in PL and the channel number 1 is set in CL.

As described above, if the value of P is not 0 in step E3, the steps from E2 to E8 are performed until the value of CC becomes 8 in step E8, that is, until the priorities of all the channels are searched. Is repeatedly executed to search for the channel (CL channel number) of the lowest priority (8 in the example of FIG. 6) among all the channels. Then, the value of CL is held as the assigned channel number (step E9). In the example of FIG. 6, channel number 5 is held. If the value of P is 0 in step E3 and the channel under investigation is in a mute state, a sounding event is unconditionally assigned to the channel. After setting the channel number to CL in step E4, Proceeding to step E9, the value of CL is held as the assigned channel number.

After the channel number of the lowest priority sound generation event is held in step E9, the process proceeds to step E10, where the priority of the currently generated sound generation event is calculated and stored in the register SC. Next, it is determined whether or not the value of the priority of the PL is smaller than the value of the priority of the SC (step E11). When the priority of the PL is lower than the priority of the SC, the sounding event to be generated this time can be assigned to the currently designated channel. In this case, it is determined whether or not PL is 0, that is, whether or not the priority is 0 and the sound is muted (step E1).
2).

If the PL is not 0, since the sounding event level in the assigned channel number is not 0 (silence), a forced first dump process is performed to forcibly mute the sounding event (step E1).
3). On the other hand, when PL is 0, the channel is already in the mute state, and there is no need to perform forced first processing. After the forced first dump processing in step E13, or in step E12, the PL becomes 0.
If it is (mute state), the sound generation flag HF is set to 1 (step E14). In step E11, when the priority of the PL is equal to or higher than the priority of the SC,
This pronunciation event is not pronounced. In this case, H
F is set to 0 (step E15). After setting HF to 1 or 0, the process returns to the main flow of FIG.

In the tone generation process of step A6 in the main flow, if the value of HF is 1 for the tone generation event of the input MIDI data, the tone generation process for that tone generation event is executed, and the value of HF becomes If it is 0, the sound generation event is not sounded and is ignored.

In this embodiment, when a new tone generation event occurs when all of the channels are in the tone generation state, the priority of the new tone generation event is the lowest priority of the tone generation events being sounded. If it is higher, the sounding event of the sounding channel is forcibly muted and a new sounding event is assigned, and the priority is calculated by pitch bend, vibrato, portamento, monopressure, polypressure as shown in Expression 8. ,
The priority is calculated by considering all seven factors of velocity and touch sense.

However, to calculate the priority,
Priority may be calculated based on pitch bend, vibrato, and portamento, which are factors for sounding parts used mainly in solo performances, and the priority of sounding parts such as solo performances may be increased. In addition, mono-pressure, poly-pressure,
The priority may be calculated based on the factors of velocity and touch sense, and the configuration may be such that the priority of a sounding channel (voice) to which the player intentionally adds a musical effect becomes higher. That is, the configuration of the above embodiment is
The invention includes a first invention in which priority is determined with emphasis on a pronunciation part, and a second invention in which priority is determined with emphasis on timbre change.

As described above, the musical tone generating apparatus of the above embodiment adds a musical effect to a sound event assigned to each sound channel when a plurality of sound parts are shared by a predetermined number of sound channels. The priority is calculated according to the type of the control data and each sounding part, and when a new sounding event occurs when all sounding channels are sounding, the priority of the new sounding event is changed to the sounding tone. When the priority is higher than the lowest priority among the sounding events, the sounding event of the sounding channel is forcibly muted and a new sounding event is assigned.

The program of the above-described embodiment is a program for tone generation processing executed by a computer of the tone generator, and is assigned to each tone channel of tone generating means for sharing a plurality of tone parts by a predetermined number of tone channels. Setting a priority coefficient according to the type of control data and each sounding part for adding a musical effect to the sounding event to be played, and a new sounding event when all of a predetermined number of sounding channels are sounding. Is generated, the priority of the sounding event being sounded in each sounding channel is calculated based on the priority coefficient, and the lowest priority among the priorities of each sounding channel calculated by the calculating step is Determining whether it is lower than the priority of the new pronunciation event; When the lowest priority is determined to be lower than the priority of the new sound event by the determining step, the sound event having the lowest priority is forcibly muted and the new sound event is assigned to the sound channel. And a step.
That is, this program causes the computer of the musical sound generation device to function as a plurality of means for executing each processing in the musical sound generation processing.

Therefore, according to the musical tone generating apparatus or the musical tone generating program having such a configuration, when a new tone generating event occurs when all of the predetermined number of tone generating channels are in a tone emitting state, the tone generating tone generating means is not activated. Even if an assignment process is performed to forcibly mute the sounding event and secure a sounding channel, there is no musically unnatural effect.

In the above embodiment, the priority coefficient is set according to each sounding part. In this case, a high priority is set to the sounding part of the main melody, such as a melody part. Further, in the above embodiment, the priority coefficient is set in accordance with the type of control data to which a musical effect is added, that is, pitch bend, vibrato, and portamento. Set a high priority.

Further, the tone generator of the above embodiment, when assigning a tone generation event to each tone generation channel of the tone generation means having a predetermined number of tone generation channels, gives a tone color change to the tone generation event assigned to each tone generation channel. The priority is calculated according to the type of control data, and when a new sounding event occurs when all sounding channels are sounding, the priority of the new sounding event is determined by the priority of the sounding event being sounded. If the priority is higher than the lowest priority, the sound generation event of the sound channel is forcibly muted and a new sound event is assigned.

The program of the above-described embodiment is a program for a tone generation process executed by a computer of a tone generator, and executes a sound generation event assigned to each sound channel of a sound generator having a predetermined number of sound channels. Setting a priority coefficient in accordance with a type of control data for giving a tone change; and, when all of a predetermined number of sounding channels are in a sounding state, when a sounding event to be newly sounded occurs, a sound is generated in each sounding channel. Calculating the priority for the sounding event being sounded based on the priority coefficient, and the lowest priority of the priorities of each sounding channel calculated by the calculating step is lower than the priority of the new sounding event And the step of determining whether or not Forcibly muting the sound event of the lowest priority when the previous degree is determined to be lower than the priority of the new sound event and assigning a new sound event to the sound channel. I have. That is, this program also causes the computer of the musical sound generation device to function as a plurality of means for executing each processing in the musical sound generation processing.

Therefore, according to the musical tone generating apparatus or the musical tone generating processing program having such a configuration, when a new tone generating event occurs when all of the predetermined number of tone generating channels are in a tone emitting state, the tone generating tone generating means is not activated. Even if an assignment process is performed to forcibly mute the sounding event and secure a sounding channel, there is no musically unnatural effect.

In the above embodiment, the priority coefficient is set according to the type of the control data that gives the timbre change. In this case, the higher the timbre change amount given by the control data is, the higher the priority is set. I do.

Further, according to the above-described embodiment, the first invention that determines the priority with emphasis on the tone generation part and the second invention that determines the priority with emphasis on the tone color change are synthesized. That is, it is also apparent that the third aspect of the invention determines the priority with emphasis on the tone generation part and tone color change, as in the calculation shown in Expression 8. In this case, a priority coefficient is set for a tone event assigned to each tone channel of the tone generating means that shares a plurality of tone parts with a predetermined number of tone channels in accordance with a tone color change and each tone part.

In the above embodiment, the MIDI
The case where assignment processing based on priority is performed for data input has been described. However, even when keyboard input is set in the flow of FIG. 8, control data included in performance data input from the keyboard, each sound generation An assignment process based on priority may be performed on keyboard input in accordance with a sounding part specified for a channel.

[0046]

According to the present invention, when a new sounding event occurs when all of the predetermined number of sounding channels are in a sounding state, the sounding event being sounded is forcibly muted to change the sounding channel. Even if the assignment process for securing is performed, there is no musically unnatural effect.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a musical sound generator according to the present invention.

FIG. 2 is a diagram showing a data configuration of an area of a RAM in FIG. 1;

FIG. 3 is a diagram showing a data configuration example of a tone color parameter in FIG. 2;

FIG. 4 is a view showing an example of a data configuration of a device total parameter in FIG. 2;

FIG. 5 is a diagram showing an example of a data configuration of sounding part parameters in FIG. 2;

FIG. 6 is a diagram showing a data configuration example of channel priority in FIG. 2;

FIG. 7 is a main flowchart showing the operation of the CPU in FIG. 1;

FIG. 8 is a flowchart of a switch process in FIG. 4;

FIG. 9 is a flowchart of a MIDI process in FIG. 4;

FIG. 10 is a flowchart of priority recalculation in FIG. 9;

FIG. 11 is a flowchart of an assignment process in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CPU 3 ROM 4 RAM 5 Keyboard 6 Switch part 7 MIDI interface 8 Sound source LSI

Claims (12)

[Claims] 1. A method according to claim 1, wherein a plurality of sound channels are assigned to a plurality of sound channels by a predetermined number of sound channels. Setting means for setting a degree coefficient; when all of the predetermined number of sounding channels are in a sounding state, when a new sounding event occurs, priority is given to the sounding event being sounded in each sounding channel and the new sounding event. Calculating means for calculating the degree based on the priority coefficient; and determining whether the lowest priority among the priorities of each sounding channel calculated by the calculating means is lower than the priority of the new sounding event. And determining that the lowest priority is lower than the priority of the new sounding event. Allocating means for forcibly silencing the lowest priority sound generation event when the judgment is made and allocating the new sound generation event to the sound generation channel. 2. The musical tone generating apparatus according to claim 1, wherein said setting means sets a high priority coefficient for a sounding part of a main melody. 3. The tone generator according to claim 1, wherein the setting means sets a higher coefficient as the amount of the musical effect added by the control data increases. 4. The tone generating apparatus according to claim 1, wherein said setting means sets a priority coefficient in accordance with a type of control data for giving a tone change and each of said tone generation parts. 5. A setting means for setting a priority coefficient in accordance with a type of control data for giving a timbre change to a sounding event assigned to each sounding channel of a sounding means having a predetermined number of sounding channels; Calculating means for calculating a priority of a sounding event being sounded in each sounding channel based on the priority coefficient when a new sounding event occurs when all of the sounding channels are sounding; Determining means for determining whether or not the lowest priority of the priorities of the respective sounding channels calculated is lower than the priority of the new sounding event; and If it is determined that the sounding event is lower than the priority of the sounding event, the sounding event with the lowest priority is forcibly muted and Allocating means for allocating the new sounding event to a sounding channel. 6. The tone generator according to claim 4, wherein said setting means sets a higher coefficient as the tone change amount given by said control data is larger. 7. A program for tone generation processing executed by a computer of a tone generator, wherein a tone generation event is assigned to each tone generation channel of a tone generation means for sharing a plurality of tone generation parts by a predetermined number of tone generation channels. Setting a priority coefficient in accordance with the type of control data to which a musical effect is added and each sounding part; and when a new sounding event occurs when all of the predetermined number of sounding channels are sounding. Calculating the priority of the sounding event that is sounding in each sounding channel based on the priority coefficient; and determining the lowest priority among the priorities of the sounding channels calculated by the calculating step. Determining whether the event priority is lower than the priority of the event; And when the lowest priority is determined to be lower than the priority of the new sound event, the sound event of the lowest priority is forcibly muted and the new sound event is assigned to the sound channel. A program for music tone generation processing, comprising: 8. The program according to claim 7, wherein said setting step sets a high priority coefficient for a tone generation part of a main melody. 9. The non-transitory computer-readable storage medium according to claim 7, wherein the setting step sets a higher coefficient as the amount of the musical effect added by the control data increases. 10. The program according to claim 7, wherein said setting step sets a priority coefficient according to a type of control data for giving a tone change and each of said tone generation parts. 11. A program for tone generation processing executed by a computer of a tone generator, the control data being for giving a tone change to a tone generation event assigned to each tone generation channel of a tone generation means having a predetermined number of tone generation channels. Setting a priority coefficient according to the type of a sounding event; and when a sounding event to be newly sounded occurs when all of the predetermined number of sounding channels are sounding, a sounding event being sounded in each sounding channel. Calculating the priority of the sounding channel based on the priority coefficient, and determining whether the lowest priority among the priorities of the respective sounding channels calculated by the calculating step is lower than the priority of the new sounding event. Determining the lowest priority by the determining step. Forcibly silencing the lowest priority sounding event when it is determined to be lower than the priority of the new sounding event, and assigning the new sounding event to the sounding channel. Music generation processing program. 12. The program according to claim 10, wherein the setting step sets a higher coefficient as the tone change amount given by the control data is larger.