JPH08179767A - Electronic musical instrument - Google Patents

Abstract

PURPOSE: To naturally and efficiently determine pronouncing channels to be truncated by truncating the tone generation channels whose envelope level at that time is not more than a prescribed level when a new demand for tone generation processing is made. CONSTITUTION: A musical sound synthesizing circuit 19 has plural tone generation channels to synthesize a musical sound on the basis of tone generation indication from a CPU 15, and outputs musical sound signals synthesized by the plural tone generation channels to a sound system 20. The sound system 20 generates the musical sound signals outputted from the musical sound synthesizing circuit 19 as musical sounds. Here, envelope levels of the respective tone generating channels are read out in order, and the envelope levels and a prescribed level are compared with each other. When tone generating channels whose envelope level is not more than the prescribed level are detected, tone generating channels on and after it are truncated. In this reading-out order, first of all, order put in an OFF condition is set as old order, and next, order put in an ON condition is set as old order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic musical instrument, and more particularly, it has a plurality of tone generation channels for generating musical tones whose volume changes with the passage of time, and has good allocation processing for allocating tone generation channels to musical tones to be generated. The electronic musical instruments that can be performed.

[0002]

2. Description of the Related Art A tone generation channel of an electronic musical instrument has a waveform synthesizing circuit for reading out waveform data stored in a memory in response to a player's keyboard operation and the like. It is composed of an envelope forming circuit for generating an envelope signal for controlling the volume.

In this type of electronic musical instrument, a tone generation channel is dynamically assigned to each musical tone to be generated. One tone generation channel is assigned when there is a tone generation request by the player's keyboard operation or the like. If there is no free channel, the tone generation channel previously assigned to the tone generation request is forcibly released, and this tone generation channel is assigned to the newly requested tone generation. This allocation process is called a truncate process.

Some of the musical tones have different speeds of release, those of slow attack tones such as strings and pipe organs, and those of which the attack is intentionally delayed called key-on delay. . In the conventional electronic musical instrument, since the truncation processing is performed only based on the level of the envelope signal, the following inconveniences occur.

As shown in FIG. 10, the level L _c of the envelope signal at the time t ₁ of the tone generation channel C to which the slow attack tone color is assigned is the rising portion of the musical tone but the tone generation channel. It is smaller than the levels L _a and L _b of the envelope signals at time t ₁ of A and B. When there is a tone generation channel allocation request at time t ₁ , if the truncation process is performed based only on the level of the envelope signal, the tone generation channel C will be truncated. This is unnatural because the musical sound assigned to the sounding channel C is muted without being sounded.

Therefore, there has been proposed a method of detecting the tone generation channel having the oldest key depression and performing a truncation process. If there is allocation request tone generation channels at time t _1, even though the level of the envelope signal at time t ₁ is smaller for the sound channel A than sound channel B, truncated the oldest depressed the sound channel B Will be done. This is unnatural because the sound that is still heard will be muted earlier than the sound that is actually attenuated.

A truncation method for eliminating such an unnaturalness is disclosed in Japanese Patent Laid-Open No. 5-265458. This method truncates the tone generation channel having the lowest envelope signal level among the tone generation channels assigned to the already released keys. According to this truncation processing, it is possible to prevent truncation of a tone generation channel having a relatively high envelope signal level, although the key is released.

[0008]

The optimum sounding channel can be truncated by truncating the sounding channel with the lowest envelope signal level among the sounding channels assigned to the already released keys. . However, as the number of released tone channels increases, the time for searching the tone channel with the lowest envelope signal level increases. If the search time becomes long, there is a time delay between the key being pressed and the actual pronunciation, which sounds unnatural.

It is an object of the present invention to provide an electronic musical instrument that is musically natural and can efficiently determine a tone generation channel to be truncated.

[0010]

The electronic musical instrument of the present invention indicates the pitch of a musical tone to be sounded and can be in either an on state or an off state, and a note code for the note code. "Note on" when the start of pronunciation is instructed, and "Note off" when the end of pronunciation is instructed
Performance input means for generating a sounding processing request including an on / off type, and the note code are dynamically assigned,
According to the assigned note code and on / off type, a musical tone synthesizing unit having a plurality of tone generation channels for generating a tone waveform whose envelope level changes with time, the plurality of tone generation channels, and a plurality of tone generation channels assigned to each tone generation channel. Sounding assignment information storage means for storing the note code in association with the existing note code so that the order in which the note code is turned on and the order in which the note code is turned off can be understood
A sounding process request detecting unit that detects that there is a sounding process request from the performance input unit; and when the sounding process request detecting unit detects a sounding process request, the on / off type is “note on”, If there is no empty channel in the channels, the sounding assignment information storage means is searched in a predetermined order and detected until a sounding channel having an envelope level smaller than a predetermined level at that time is detected. The generation of the musical tone waveform of the sound generation channel is stopped, and a musical tone waveform corresponding to the note-off on / off type "note-on" is newly generated, and the pronunciation allocation information storage means is caused to perform the tone generation processing. Detected sound channel and sound processing request so that you can see the order in which the requested note code was turned on If there is a new note code stored in association with it, and if the on / off type is "note off", the on / off type is assigned to the sound generation channel assigned to the note code for which the sound generation processing request has been made. Generates a tone waveform corresponding to "note-off", and stores it in the pronunciation assignment information storage means so that the note code for which the pronunciation processing request has been made is in an off-state so that the order of the off-state can be known. Control means,
The predetermined order is the order of the note chords in the off state at that time, then the note chords in the on state, and in the note chords in the off state, the order in which they are in the off state and the note chords in the on state. And the control means in the order of being turned on.

[0011]

When a new tone generation processing request is made, the tone generation channel whose envelope level at that time is below a predetermined level is truncated. By appropriately determining the predetermined level, it is possible to prevent the unnaturalness caused by muting the musical sound generated by the truncated sound generation channel.

The envelope level of each tone generation channel is read in order and the envelope level is compared with a predetermined level. When a tone generation channel whose envelope level is lower than a predetermined level is detected, it is not necessary to read the envelope level of the tone generation channels thereafter. Since it is not necessary to read the envelope levels of all the sound generation channels, the sound generation channels to be truncated can be detected in a relatively short time.

It is expected that a tone generation channel assigned to a note code whose turn-off state is older is lower in envelope level. Further, in the note code in the on state, it is expected that the tone generation channel assigned to the key whose turn-on state becomes older has a lower envelope level. By detecting the order of reading the envelope level of the sound generation channel, the sound generation channel having the envelope level lower than the predetermined level is detected by setting the order of the off state to the oldest first and then the order of the on state to the oldest. It can be expected that the time to

[0014]

An embodiment of the present invention will be described below.
FIG. 1 is a block diagram showing the overall configuration of an electronic musical instrument according to an embodiment of the present invention. A plurality of modules are connected to the data bus 18, and data is exchanged between the modules via the data bus 18 to perform a performance.
The performance input unit 11 has a plurality of keyboards, detects key depression and key release of the keyboard, and supplies pitch information, key release speed information and the like to the data bus 18. The MIDI interface 14 has
A MIDI terminal is provided, and receives a MIDI message input from the MIDI terminal and supplies it to the data bus 18.

The display board 12 displays the selected tone color information and the like. The panel switch 13 is for selecting a tone color and the like, and supplies tone color information and the like to the data bus 18. The CPU 15 executes processing according to the program stored in the ROM 16. The RAM 17 is a memory for storing temporary data required for processing.

The voice synthesizing circuit 19 has a plurality of tone generation channels for synthesizing a tone based on a tone generation instruction from the CPU 15, and outputs the tone signal synthesized by the plurality of tone generation channels to the sound system 20. Sound system 2
0 is D / A-converts and amplifies the tone signal output from the tone signal synthesis circuit 19 to generate a tone.

Next, the CPU of the electronic musical instrument having the configuration shown in FIG.
The operation of 15 will be described with reference to FIGS.
FIG. 2 shows a flowchart of the main routine of the CPU 15. When the power of the electronic musical instrument is turned on, the CPU 15
Executes step SA1. In step SA1,
Initialize each part of the device. For example, the registers in each module are reset and various variables are initialized. When the initial setting is completed, the CPU 15 sets M in step SA2.
IDI processing, key processing in step SA3, and step S
A4 panel processing is performed. When the process of step SA4 is completed, the process returns to step SA2, and steps SA2 to SA4 are repeatedly executed until the power is turned off.

The key processing in step SA3 will be described below.
Next, panel processing in step SA4, and finally step SA
The MIDI processing of No. 2 will be described. FIG. 3 shows a flowchart of the key processing. The processing of the CPU 15 is step S in FIG.
Proceeding to A3, the key processing routine shown in FIG. 3 is started. When the key processing routine is activated, the CPU 15 executes the processing of step SB1. In step SB1, the keyboard of the performance input section 11 is scanned to detect the key press / release state. When scanning of all keyboards is completed, the process proceeds to step SB2.

In step SB2, it is determined whether or not there is a key event based on the key press / release state detected in step SB1. For example, if the scan result of the previous cycle is the key release state and the scan result of the current cycle is the key press state, it means that there is a key press in the current cycle, and the key event indicates that there is a key press. "become. On the contrary, if the scan result of the previous cycle is the key pressed state and the scan result of the current cycle is the key released state, the key event is “key off” indicating that the key was released. Also,
If the state of the previous cycle and the current cycle are the same for all the keys, no key event is detected.

If no key event is detected, nothing is returned to the main routine shown in FIG. If a key event is detected, the process proceeds to step SB3. In step SB3, pronunciation information on all key events is stored in the MIDI buffer of the RAM 17. The pronunciation information is, for example, a key code (K
C), key velocity (KV) indicating the speed of pressing and releasing keys, and the like. When all the key event information is stored in the MIDI buffer, the process returns to the main routine shown in FIG.

In the above description of the key processing routine, the case where the key depression / release of the keyboard is detected has been described, but the same processing is performed when a performance input is made from the MIDI interface 14. That is, when the MIDI message is received, the pronunciation information specified by the MIDI message is stored in the MIDI buffer.

Hereinafter, the inputs from the performance input section 11 and the MIDI interface 14 are generically called MIDI events. The number of channels of the normal MIDI standard is 16 channels from 0 to 15, and M
The MIDI message input from the IDI input terminal includes this MIDI channel information. In this embodiment, the MIDI channels are expanded in the internal processing to secure the number of channels of 16 or more. Hereinafter, the MIDI channel in the message input from the MIDI input terminal is called an external MIDI channel, and the extended MIDI channel used internally is simply called a MIDI channel.

In order to distinguish the input from the keyboard and the input from the MIDI input terminal, different MIDI channels are assigned to each. For example, the MIDI channel 0 is assigned to the input information from the keyboard, and the MIDI channel obtained by adding a fixed value to the external MIDI channel is assigned to the information from the MIDI input terminal. RA
The pronunciation information stored in the M17 MIDI buffer includes
This MIDI channel is also included.

Next, the panel processing of step SA4 shown in FIG. 2 will be described. When the performer operates the panel switch 13 shown in FIG. 1, the musical style and tempo are set, or the tone color for each MIDI channel is set according to the operation. The musical style, tempo, tone color, etc. are stored in the RAM 17. These tone color information and the like are used in the MIDI processing described below.

Next, the MIDI processing of step SA2 shown in FIG. 2 will be described with reference to FIGS. FIG.
Shows a flowchart of MIDI processing. CPU15
2 proceeds to step SA2 in FIG. 2, M shown in FIG.
The IDI process is activated. CPU15, step SC
After scanning the MIDI buffer of the RAM 17 at 1, the process proceeds to step SC2.

In step SC2, it is determined whether or not there is a MIDI event. If no MIDI event is detected, nothing is done and the process returns to the main routine of FIG. If the MIDI event is detected, the process proceeds to step SC3.

In step SC3, it is determined whether the MIDI event is a note event. Here, the note event refers to an event representing a key release. When the MIDI event is a note event, the note event process of step SC4 is executed, and when it is not a note event,
The process corresponding to each event in step SC5 is executed. When the processing of step SC4 or SC5 ends, the process returns to the main routine of FIG.

Next, the note event process will be described with reference to FIGS. In the following description, the case where a key is released from the performance input section 11 will be described.
The same processing is performed when a MIDI message corresponding to key release is input from the input terminal.

FIG. 5 shows a flow chart of note event processing. The processing of the CPU 15 is step SC4 in FIG.
When the process proceeds to step 5, the note event process of FIG. 5 is activated. At step SD1, the CPU 15 sends the MIDI data in the RAM 17
The pronunciation information stored in the buffer is retrieved. The pronunciation information includes a key event indicating the distinction between "key on" and "key off", a key code, a key velocity, a MIDI channel, etc., as described above.

In step SD2, it is determined whether the key event is "key on". When the key event is "key on", a series of processes of steps SD3 to SD12 for producing a tone corresponding to the depressed key are executed. If the key event is "key off", a series of key off processing of steps SD13 to SD15 is executed.

First, with reference to FIG. 6A, the processing at the time of releasing the key in steps SD13 to SD15 will be described. Figure 6
(A) shows the movement of the key assignment table when releasing the key. Here, the key assignment table refers to a table in which information elements indicating the correspondence between key codes and sounding channels are arranged in a predetermined order, and is stored in the RAM 17. FIG. 6A shows a case where eight tone generation channels 0 to 7 are prepared. The table shown on the left side of FIG. 6A shows the state before the key release process, and the table shown on the right side shows the state after the key release process.

The five rows from the top of the table before the key release processing are the key release information areas that represent the keys that have already been released, and the three rows from the bottom are the key release information areas that represent the keys being pressed. is there. For example, the key code 36 has already been released and is assigned to the sound generation channel 7. The key code 42 is currently being depressed and is assigned to the tone generation channel 0.
The number of information elements stored in the key release information area and the key release information area varies depending on the key release state at that time.

In step SD13, the key assignment table is scanned to retrieve the key code retrieved from the MIDI buffer, that is, the key code released in this cycle,
Get the assigned pronunciation channel number. For example, assuming that the released key code is 61, the key code shown in FIG.
The tone generation channel number 5 assigned to the key code 61 is obtained from the pre-key release processing table of (A).

At step SD14, a "key-off" signal is sent to the tone generation channel assigned to the released key code. Upon receiving the "key-off" signal, the tone synthesis circuit 19 generates a tone signal after key release from the corresponding sounding channel. The control information of the tone signal after key release is stored in advance in the ROM 16 for each tone color designated by the panel switch 13. The tone synthesis circuit 19 generates a tone signal based on this control information. As a result, the envelope waveform enters a release state in which it gradually attenuates. The control information stored in the ROM 16 is
The CPU 15 reads it and transfers it to the voice synthesis circuit 19.

In step SD15, the information element relating to the released key is moved to the end of the key release information area of the key assignment table. When the released key is the key code 61, the information element related to the key code 61 is moved to the end of the key release information area, as shown in FIG. In this way, in the key release information area, the information elements related to the key code are arranged in the order of old key release from the top.

Next, with reference to FIG. 6B, the key depression processing of steps SD3 to SD12 will be described. The table shown on the left side of FIG. 6B shows the state before the key pressing process, and the table shown on the right side shows the state after the key pressing process.

At step SD3, 0 is substituted for the variable i, and a series of processes of steps SD4 to SD6 are executed. At step SD7, 1 is added to the variable i, and at step SD8 the variable i is added.
Is compared with the number of sound generation channels, and if they are not equal, the process returns to step SD4. That is, steps SD4 to SD
A series of processing of 6 is repeatedly executed for the number of sound generation channels.

In step SD4, the tone generation channel number corresponding to the i-th (starting from 0) information element of the key assignment table is obtained. For example, if i is 2, the tone generation channel number 1 is obtained corresponding to the second information element from the top in FIG.

At step SD5, the envelope level of the tone generation channel obtained at step SD4 is obtained. The envelope level is stored in the temporary memory provided for each tone generation channel in the tone synthesis circuit 19,
The CPU 15 uses the data bus 18 to synthesize the musical sound synthesis circuit 19
Read the envelope level from.

At step SD6, the envelope level obtained at step SD5 is compared with a predetermined truncation level. If the envelope level is equal to or lower than the truncate level, the loop process of steps SD4 to SD8 is skipped and the process proceeds to step SD9. If the envelope level is higher than the truncate level, the process proceeds to step SD7 and, as described above, steps SD4 to
The loop process of SD8 is repeated.

In step SD9, the tone generation ending process of the tone generation channel whose envelope level is determined to be lower than the truncated level in step SD6 is performed. As a result, the tone signal synthesizing circuit 19 stops the generation of tone signals from the corresponding tone generation channel.

In step SD10, new tone generation information is sent to the tone generation channel in which the generation of the tone signal is stopped in step SD9. The corresponding tone generation channel of the tone signal synthesis circuit 19 generates a tone signal based on the tone information sent from the CPU 15.

At step SD11, the i-th information element of the key assignment table is deleted, and the i + 1th and subsequent information elements are packed up one by one. In step SD12,
The tone generation channel stored in the i-th information element is assigned to the key code of the depressed key, and is registered at the end of the key depression information area of the key assignment table.

In FIG. 6B, the depressed key code is 4
3. Steps SD11 and SD1 when the envelope level of the sounding channel 7 is below the truncate level
9 shows changes in the key assignment table in the process of 2.
First, the envelope level of the tone generation channel is obtained in order from the top of the key release information area of the key assignment table before the key depression processing. Since it was assumed that the envelope level of pronunciation channel 7 was below the truncate level, key code 3
6. Delete the 0th information element associated with the pronunciation channel 7.

Next, as shown in the key assignment table after the key depression processing of FIG.
The tone generation channel 7 is assigned to and is registered at the end of the key depression information area of the key assignment table. As a result, in the key-depression information area of the key assignment table, the key codes currently being depressed are lined up in the order of oldest key-depression.

In the above embodiment, the key assignment table is searched in order from the top, and the search is ended when the envelope level of the tone generation channel is detected to be below the truncation level. Since it is not necessary to read the envelope level for all the sound generation channels, the processing speed can be increased. Further, since the information elements are arranged in the key assignment table in the order of the oldest released key and the next oldest pressed key, the pronunciation channels that are considered to have a low envelope level are preferentially searched. .
As a result, it is possible to find out a sounding channel below the truncated level more quickly.

In the above embodiment, the key assignment table is divided into two areas, a key release information area and a key depression information area,
The case where the keys are arranged in order from the oldest pressed and released keys has been described, but an empty tone generation channel area may be further provided. In the empty tone generation channel area, tone generation channel numbers not assigned to the key code are stored. For example, a tone generation channel in which the envelope level becomes 0 due to natural attenuation may be detected, and this tone generation channel may be registered in the empty tone generation channel area. When there is a new key depression, any tone generation channel in the empty tone generation channel area may be assigned to the key code having the key depression.

The truncate level may be a constant level regardless of tone color and tone pitch, or may be weighted for each tone color or tone pitch. When the truncation level is set to a constant level, for example, when the maximum envelope level value is 0 dB, it may be about −70 dB. In addition, weighting the truncate level corresponds to the fact that even if the volume is the same, the influence on human hearing depends on the pitch and the like. For example, trebles may be more prominent than basses, or lowest notes may be musically important, even at the same volume. By weighting the truncation level, it is possible to mute the human ear so that it sounds more natural.

In the above embodiment, the case where the current envelope level and the truncated level are compared in the note event process has been described, but this comparison process may be applied to real time control. Here, the real-time control refers to control in which a musical sound is changed in real time by an after-touch, a pitch bend wheel, or the like other than a key press / release event.

Next, an embodiment in which the comparison processing between the envelope level and the truncate level is applied to the real-time control will be described. First, the configuration of the tone synthesis circuit 19 will be described with reference to FIG.

FIG. 7A shows a block diagram of the tone synthesis circuit 19. Pronunciation information supply circuit 31, envelope data RAM 35, and filter envelope data RAM 3
8 is connected to the interface circuit 30. The interface circuit 30 is connected to the data bus 18 shown in FIG. 1 and transmits / receives data to / from the CPU 15.

The pronunciation information is input from the CPU 15 to the pronunciation information supply circuit 31 via the interface circuit 30.
The pronunciation information supply circuit 31 supplies pronunciation information to each block in the tone synthesis circuit 19.

The waveform synthesizing circuit 32 is used by the sound information supplying circuit 3
Based on the pronunciation information supplied from No. 1, the waveform of the corresponding pitch and tone color is synthesized. The combined waveform is input to the envelope circuit 33.

The envelope circuit 33 is a waveform synthesis circuit 32.
An amplitude envelope is added to the waveform input from. The amplitude envelope to be given is stored in the envelope data RAM 35 when the key is pressed. Specifically, the initial value of the amplitude envelope, the target value, and the interpolation rate are stored.

The amplitude envelope forming circuit 34 uses the initial value as the current value when a key is pressed, performs interpolation processing from the current value toward the target value at the specified interpolation rate, and updates the current value of the envelope in a constant cycle. By this interpolation processing, envelope waveforms such as attack, decay, sustain and release of musical tones are generated. The current value of the amplitude envelope is supplied to the envelope circuit 33, and the envelope circuit 33 adds the amplitude envelope to the waveform input from the waveform synthesis circuit 32 based on this current value. The waveform provided with the amplitude envelope is supplied to the filter circuit 36.

The filter circuit 36 filters the waveform input from the envelope circuit 33 based on the cutoff frequency given from the filter envelope forming circuit 37. The filter circuit 32 is, for example, a digital low pass filter.

The filter envelope data RAM 38 stores the cutoff center frequency, the initial value of the cutoff frequency multiplication coefficient, the target value, and the interpolation rate when the key is pressed. The filter envelope forming circuit 37 sets the initial value as the current value when the key is pressed, performs interpolation processing from the current value toward the target value at the specified interpolation rate, and updates the current value of the multiplication coefficient at a constant cycle. Further, the cutoff center frequency is multiplied by the current value of the multiplication coefficient to obtain the current cutoff frequency, and the cutoff frequency is supplied to the filter circuit 36.

The filter circuit 36 filters the waveform input from the envelope circuit 33 based on the cutoff frequency designated by the filter envelope forming circuit 37. The filtered waveform is provided to the sound system 20 of FIG.

For example, the sound at the beginning of the keystroke of a piano contains a lot of noise components, but the high frequency components decay quickly with time, and finally only the fundamental frequency components and low-order high frequency components remain. To electronically synthesize this sound, the cutoff frequency of the low-pass filter may be lowered with time.

FIG. 7B shows an example of the filter envelope. The horizontal axis represents time, and the vertical axis represents the difference of the cutoff frequency from the standard value. The table in the graph shows the target value corresponding to the filter envelope waveform shown by the polygonal line in FIG. 7B and the slope corresponding to the interpolation rate. The initial value of the multiplication coefficient is 1, and the cutoff frequency is equal to the cutoff center frequency. Since the initial target value is 1 and is equal to the current value, the multiplication coefficient holds 1. When the current value and the target value are equal, the numerical value specified by "slope" is interpreted as the time to hold the current value.

When the time for holding the current value has elapsed, the multiplication coefficient increases with a slope of 1 toward the target value 2. Target value 2
When reaching, the slope decreases toward the target value 0.5 at -1.5. After that, this operation is repeated to generate the filter envelope waveform. When "hold" is specified for "tilt", the current value is held until the end of sounding. This filter envelope waveform is set for each timbre.

In the case of an electronic musical instrument, a key aftertouch,
A method of changing the cutoff frequency of the low pass filter by controlling the pitch bend wheel or the like is also adopted. Therefore, it becomes necessary to perform real-time control in which the waveform of the filter envelope is changed after sounding. In real-time control, a preset filter envelope waveform is changed in real time.

Next, the real-time control will be described with reference to FIGS. The real-time control parameter is input to, for example, an A / D input terminal provided in the CPU 15. For example, an after touch sensor common to all keys of the performance input unit 11 is provided, and an output signal of the after touch sensor is input to the A / D input terminal of the CPU 15.
Alternatively, the CPU 15 may be provided with a plurality of A / D input terminals to input the output signal of the pitch bent wheel or the like.

FIG. 8 shows a flowchart of real-time control. The real-time control is activated by an interrupt having a cycle of 10 ms. When the real-time control is activated, the CPU 15 proceeds to step SE1 to read the signal input to the A / D input terminal and obtain the real-time control parameter.

At step SE2, 0 is substituted for the variable i, and a series of processing from step SE3 to SE7 is executed. In step SE8, 1 is added to the variable i and step SE
In step 9, the variable i is compared with the number of sound generation channels. If the variable i is not equal to the number of sound generation channels, step SE3
Return to When the variable i is equal to the number of sound generation channels, the real-time control is ended and the process before interruption is restarted.
That is, the processes of steps SE3 to SE7 are repeatedly executed for the number of sound generation channels.

In step SE3, the tone generation channel number corresponding to the i-th information element of the key assignment table shown in FIG. 6 is obtained. In step SE4, step SE3
Obtain the envelope level of the sounding channel obtained in. In step SE5, the envelope level obtained in step SE4 is compared with a predetermined real-time control target level. The processing of steps SE3 to SE5 is shown in FIG.
This is the same processing as steps SD4 to SD6 of the note event processing shown in FIG.

If the envelope level is higher than the real-time control target level, the process proceeds to step SE6 to execute the filter control. If the envelope level is equal to or lower than the real-time control target level, the filter control is not performed and the process proceeds to step SE8. That is, the filter control is performed only for the tone generation channels that generate the tone signal whose envelope level is higher than the real-time control target level, and the filter control is not performed for the other tone generation channels. The filter control will be described later in detail with reference to FIG.

This is based on the idea that the filter control has little effect on the musical sound whose volume is already attenuated and cannot be heard by the human ear. As described above, by eliminating the filter control for the tone generation channel that does not substantially need the filter control, it is possible to reduce the number of steps of the real-time control without losing the unnaturalness of the musical sound.

In the note event process, as shown in step SD6 of FIG. 5, when the tone generation channel having the envelope level equal to or lower than the truncation level is found, the search of the key assignment table is ended. In contrast,
In real-time control, all key assignment tables are searched every cycle. As described above, the number of steps of the key assignment table search increases in the real-time control, but it is within the allowable range for the following reasons.

That is, when a key depression is detected, it is necessary to immediately generate a tone corresponding to the key. If the pronunciation is delayed, unnaturalness becomes noticeable. In the case of real-time processing, since it is processing corresponding to aftertouch or pitch bend, even if the response is slightly delayed, unnaturalness is not noticeable. Thus, real-time processing is not as strict as real-time processing as note event processing. Therefore, even if the number of steps in real-time control increases, it is acceptable. For the above reason, it is preferable that the interrupt is disabled during the note event process and the note event process is executed with priority over the real-time control.

Next, the filter control will be described with reference to FIG. FIG. 9 shows a filter control flow of the musical sound synthesis circuit of FIG. When the processing of the CPU 15 proceeds to step SE6 of FIG. 8, the filter control of FIG. 9 is activated.

In step SF1, the current value and target value of the filter envelope of the tone generation channel to be processed are shown in FIG.
It is read from the envelope data RAM 34 shown in (A). In step SF2, the current value and the target value of the filter envelope are increased or decreased based on the control parameter read from the real-time control buffer in step SE1 of FIG.

At step SF3, the present value and the target value of the increased / decreased filter envelope are set to the envelope data R
Write to AM34. When the current value and the target value in the envelope data RAM 34 are rewritten, the filter envelope forming circuit 33 performs interpolation processing from the new current value toward the new target value at a predetermined interpolation rate. This makes it possible to generate a waveform different from the preset filter envelope waveform. The cutoff frequency of the filter circuit 32 changes.

Although the case where the filter envelope waveform is controlled in real time has been described with reference to FIGS. 8 and 9, the amplitude envelope waveform may be controlled in real time. Although the present invention has been described above with reference to the embodiments, the present invention is not limited thereto. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0075]

As described above, according to the present invention,
It is possible to determine the tone generation channel to be truncated with a relatively small number of processing steps. Since it is possible to truncate a sounding channel whose envelope level is too low to be heard by the human ear, it is possible to mute the sound without imparting unnaturalness.

[Brief description of drawings]

FIG. 1 is a block diagram of an electronic musical instrument according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a main routine of the CPU of the electronic musical instrument according to the embodiment of the present invention.

FIG. 3 is a flowchart of key processing.

FIG. 4 is a flowchart of MIDI processing.

FIG. 5 is a flowchart of note event processing.

FIG. 6 is a diagram showing a change of a key assignment table in a note event process at the time of key depression and key release.

7 is a block diagram of the tone synthesis circuit of FIG. 1 and a graph showing an example of changes in multiplication coefficients of a filter envelope.

FIG. 8 is a flowchart of real-time control.

FIG. 9 is a flowchart of filter control.

FIG. 10 is a graph showing the envelope level for each sound generation channel for explaining the truncation process according to the conventional example.

[Explanation of symbols]

11 performance input section, 12 display panel, 13 panel switch, 14 MIDI interface, 15 C
PU, 16 ROM, 17 RAM, 18 bus,
19 tone synthesis circuit, 20 sound system,
21 speaker, 30 interface circuit, 31
Pronunciation information supply circuit, 32 Waveform synthesis circuit, 33
Envelope circuit, 34 amplitude envelope forming circuit, 35 amplitude envelope data RAM, 36 filter circuit, 37 filter envelope forming circuit,
38 Filter envelope data RAM

Claims (1)

[Claims] 1. A note chord which indicates a pitch of a musical tone to be sounded and can be in either an on state or an off state, and "note on" when a tone generation start is instructed to the note code. And a performance input means for generating a sounding processing request including an on / off type that becomes “note off” when the end of sounding is instructed, and the note code is dynamically assigned, and the note code and the on / off type are assigned. , A musical tone synthesizing means having a plurality of sound generation channels for generating a musical tone waveform whose envelope level changes with time, the plurality of sound generation channels and the note codes assigned to the respective sound generation channels are associated with each other to generate notes. Pronunciation assignment information storage means for storing so that the order in which the chords are turned on and the order in which the chords are turned off are stored, A sounding processing request detecting means for detecting that there is a sounding processing request from the performance input means; and when the sounding processing request detecting means detects a sounding processing request, the on / off type is “note on”, and the sounding channel If there is no vacant channel, the sounding assignment information storage means is searched in a predetermined order and detected until a sounding channel having an envelope level smaller than a predetermined level is detected at that time. The generation of the tone waveform of the tone generation channel is stopped, a tone waveform corresponding to the note code on / off type of "note on" is newly generated, and the tone generation request is stored in the tone assignment information storage means. There is a detected sound channel and sound processing request so that you can see the order in which the note codes that were If a new note code is stored in association with the note code, and the on / off type is “note off”, the on / off type is set to the tone generation channel assigned to the note code for which the tone generation processing request is made. Control for generating a musical tone waveform corresponding to "note-off" and storing in the pronunciation assignment information storage means that the note code requested to be produced is in the off-state so that the order of the off-state can be known. The predetermined order is the order of the note code in the off state at that time, then the note code in the on state, and in the note code in the off state, the order in which the note is in the off state and the note code in the on state. An electronic musical instrument having the control means, which is the order in which the note code is turned on.