JPH067329B2 - Electronic musical instrument truncation device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic musical instrument having a plurality of tone generation channels, and more particularly to improvement of a truncation device for controlling pitch information allocation to each tone generation channel. is there.

SUMMARY OF THE INVENTION The present invention is an electronic musical instrument in which pitch information generated by keyboard operation or the like is assigned to an appropriate one of a plurality of tone generation channels to generate a tone, and all tone generation channels are When new pitch information is generated while in use, for example, for each channel to which a melody tone is assigned, check the consonance of the melody tone with respect to the chord, and give priority to the melody tone with the highest consonance. By eliminating the minor (dissonant) melody sound and allocating a new pitch information channel, a beautiful harmony performance sound can be generated.

[Prior Art] Conventionally, as a truncate device of an electronic musical instrument, one that detects the earliest key-off channel from a plurality of tone generation channels and assigns new pitch information to this channel is known. (For example, JP-A-51
-21813 gazette).

Further, as another conventional device, a channel having the smallest envelope value (the channel with the highest sound attenuation) is detected from a plurality of tone generation channels and new pitch information is assigned to this channel. Are known (see, for example, Japanese Patent Laid-Open No. 52-25613).

[Problems to be Solved by the Invention] According to the conventional technique as described above, when new pitch information is generated when all the tone generation channels are in use, the new pitch information is The earliest key-off channel or the most attenuated channel is assigned to the sound generation processing, and the sound previously assigned to the channel is erased.

Therefore, as an example, if the melody pitch information in the process of playing melody sounds one after another while playing chords is assigned to the channels as described above, a melody sound that is consonant with a chord (for example, Dormyso) A situation may occur in which (for example, Do) is erased and a dissonant melody sound (for example, Re) remains. When such a dissonant sound remains, the beauty of the harmony is impaired, and there is a problem that the listener feels uncomfortable.

[Means for Solving the Problems] An object of the present invention is to reduce the dissonance left in the truncation process as much as possible.

The truncate device for an electronic musical instrument according to the present invention has a first part (for example, a melody part) when new pitch information is generated from the pitch designating means including a keyboard or the like when all of the plurality of tone generation channels are in use. ), The consonance degree determining means for determining the consonance degree of the performance sound with respect to the performance content of the second part (for example, accompaniment part) for each tone generation channel to which the performance sound is assigned, and the determined consonance degree is relatively large It is characterized in that it is provided with an assigning means for prioritizing a tone generation channel having a relatively low degree of consonance determined over the tone generation channel and assigning the new pitch information thereto.

[Operation] According to the configuration of the present invention, when allocating a new pitch information channel, dissonant sounds having a low consonance degree are preferentially erased, and consonant sounds having a high consonance degree remain.
A beautiful harmony performance sound can be generated.

[Embodiment] FIG. 1 shows the configuration of an electronic musical instrument according to an embodiment of the present invention. In this electronic musical instrument, the generation of musical tones such as melody and accompaniment tones is controlled by a microcomputer. There is.

Configuration of electronic musical instrument (Fig. 1) The bus 10 includes an upper keyboard (UK) 12, a lower keyboard (LK) 14, a switch group 16, a central processing unit (CPU) 18, a program memory 20, a register group 22, and a table memory. 24, tone generator (TG) 26, etc. are connected.

UK12 is mainly used for playing melody,
The key operation information is detected for each key. The LK14 is mainly used for accompaniment performance (for example, chord performance), and key operation information is detected for each key. Regarding UK12 and LK14,
The key code value for each pitch is predetermined as shown in FIG.

The switch group 16 includes various kinds of switches for controlling musical sounds and controlling performance, and operation information is detected for each switch.

The CPU 18 executes various processes for generating musical tones according to the programs stored in the program memory 20, and these processes will be described later with reference to FIGS. 5 to 8.

The register group 22 includes a large number of registers used in various processes by the CPU 18, and the registers related to the implementation of the present invention will be described later.

The table memory 24 stores consonance degree information according to the pitch difference with respect to the root note for each chord type such as major, minor, and seventh, and as one example, the stored contents regarding the major are shown in FIG. In the example of FIG. 3, the number of semitones 0, 1, 2, ... 11 from the root is used as the pitch difference with respect to the root, and values such as 0, 1, 2, 3 are used as the consonance degree information. The dissonance degree data to be stored is stored. As an example, if the root note is C, the number of semitones 0, 4, 7 from the root note
So becomes a sound with a dissonance degree of 0 (that is, a consonance sound), and the other sounds are regarded as sounds having greater dissonance as the value of the dissonance degree data increases.

The TG 26 includes 12 musical tone generating channels (channels 0 to 11) commonly used by the UK 12 and LK 14, and an envelope generator E for each musical tone generating channel.
The tone envelope is controlled by G. The envelope generator EG sends a release end detection signal RES to the bus 10 when the envelope waveform of each tone generation channel reaches "release end" through "key on" and "key off" as shown in FIG. To do. Each release end detection signal RES is used as an interrupt instruction signal for starting the release end interrupt routine of FIG.

The TG 26 can simultaneously send up to 12 keys of musical sound signals corresponding to the key pressed by the UK 12 and / or LK 14,
The tone signal sent from 26 is converted into sound by the sound system 28.

Register Group 22 Of the registers included in the register group 22, those relevant to the implementation of the present invention are listed as follows.

(1) Event key register KEY ... This stores key code data corresponding to a key that has a key event (key on or key off).

(2) Root register ROOT ... This is the one in which root data representing the root detected based on the key depression state of the LK14 is stored. The root note data is C, C _# , D ... B.
It takes one of the values 0, 1, 2, ... 11 corresponding to each of the 12 note names.

(3) Chord type register TYPE ... This stores chord type data representing the chord type detected based on the key depression state of LK14. The chord type data takes any value of 0, 1, 2, ... 7 corresponding to each of the eight chord types of major, minor, sevens ...

(4) Pitch difference register DEG ... This stores the pitch difference data representing the pitch difference between the key having the key event and the detected root note (root note indicated by ROOT).

(5) Release end channel register ZERO ... This is a register in which the channel number where the release end occurs is set.

(6) Assigned channel register ASS ... This sets the channel number to which the event key is assigned.

(7) Key code register for each channel KC _0-11 ...
These registers correspond to channels 0 to 11, respectively, and can store the key code data from the register KEY for each register.

(8) Channel another key-on flag KON 0 to 11 _... These flags respectively correspond to the 0th to 11 channels, each flag to 1, then key-on, represents 0, key-off, respectively.

(9) per channel UK / LK flag _{UL 0 to 11 ...} These flags respectively correspond to the 0th to 11 channels, each flag is 1, then UK, 0 if L
Represent K respectively.

(10) Release end flag RE 0 to _{11 for each} channel
... These flags correspond to channels 0 to 11, respectively. If the flag is 1, it indicates that the release end (end of sound generation) has been reached, and if the flag is 0, it indicates that sound is being generated.

(11) _Dissonance degree register DIS _{0 to} 11 for each channel
These registers correspond to the 0th to 11th channels, respectively, and can store the dissonance degree data read from the table memory 24 for each register.

(12) Key-off channel register OFF ... This sets the channel number to be key-off processed.

Main Routine (Fig. 5) Fig. 5 shows the flow of processing of the main routine.
This routine is started by turning on the power.

First, in step 30, an initialization routine is executed to initialize various registers. For example, any of the registers _{KC 0 to 11} and the flag _{KON 0 to 11} 0
_Is set, and 1 is set in each of the flags RE ₀ to 11.

Next, in step 32, it is determined whether or not there is a key event in the UK 12 and LK 14, and if this determination result is affirmative (Y), the process proceeds to step 34.

In step 34, the key code data corresponding to the key with the key event is put in the register KEY. Then, the process proceeds to step 36.

In step 36, a key event processing subroutine is executed as described later with reference to FIG.

When the process of step 36 is completed or when the determination result of step 32 is negative (N), the process proceeds to step 38,
For example, other processes such as a tone color selection process according to the operation of the tone color selection switch in the switch group 16 are performed.

After step 38, the process returns to step 32 and the above processing is repeated.

Release End Interrupt Routine (FIG. 6) FIG. 6 shows the release end interrupt routine, which is performed by the envelope generator EG (first
It is started each time the release end detection signal RES is generated from the figure).

In step 40, the number of the channel in which the release end has occurred is set in the register ZERO. Then, the process proceeds to step 42.

In step 42, the release end flag RE _ZERO corresponding to the channel numbered by _ZERO is set to 1. For example, if ZERO indicates ₁₀ , the flag RE ₁₀ corresponding to the tenth channel is set to 1.

After step 42, the routine returns to the routine shown in FIG.

Outline of Assignment Process (FIG. 7) FIG. 7 shows the priority order of assigning event keys to channels when there is a key event, and the outline of the assignment process will be described with reference to this.

When there is a UK key-on event, if there is a free channel, the free channel is given top priority and an event key is assigned to it.

If there is no vacant channel, the assigned channel of the UK sound (the channel generating the UK sound) is “2” in FIG. 7,
Event key channels are assigned with priority in the order of "3", "4", "5".

First, it is checked whether or not there is a channel assigned to the key that the UK has keyed off, and if any, the channel assigned to the dissonant tone is given priority over the channel assigned to the dissonant tone and the event key is assigned to this. In this embodiment, L
By referring to the stored contents as shown in FIG. 3 for the chord designated by K14, it is determined whether the assigned note is consonant or dissonant with respect to the chord, and if dissonant, to what extent.

If there is no empty channel and there is no assigned channel of the sound keyed off for UK, the event key is assigned to the assigned channel of the sound keyed on for UK. In this case as well, as in the case of key-off, as described above, the event key is assigned to the channel to which the dissonant sound is assigned, prioritizing the channel to which the dissonant sound is assigned.

On the other hand, when there is an LK key-on event, if there is a free channel, the free channel is given the highest priority and an event key is assigned to it. If there is no vacant channel, it is checked whether there is an assigned channel for the key-off sound with respect to UK, and if there is, an event key is assigned to this. In this assignment, prioritizing the channel for dissonant sound assignment over the channel for assigning dissonant sound is the same as in the case with the above-mentioned UK key-on event.

If there is no vacant channel and there is no assigned channel for the sound keyed off with respect to the UK, no assignment processing is performed. Therefore, unlike in the case where there is a UK key-on event, the key-on sound is not erased in the UK.

In this embodiment, when there are no available channels, L
Even if there are five or more K-key-on events, only four or less keys are allocated.

Key Event Processing Subroutine (FIG. 8) FIG. 8 shows a key event processing subroutine including the assignment processing as outlined with reference to FIG.

In step 50, it is determined whether the key event is a key-on event. If the determination result is affirmative (Y), step 52
Move on to.

In step 52, it is determined whether the key-on event has occurred in the UK, and if the determination result is affirmative (Y), step
Move to 54.

In step 54, it is determined whether there is 1 in the flags RE ₀ to 11 (whether there is a channel that has reached the release end). If the result of this determination is affirmative (Y), the routine proceeds to step 56, where the number of the release-ended channel (empty channel) is set in the register ASS. For example,
If RE ₁₀ = 1 as in the above example, 10 is set in ASS.

Next, at step 58, the key code register K corresponding to the channel with the number indicated by ASS (ASS channel).
The key code data of the register KEY is stored in C _ASS and the flag UL _ASS corresponding to the ASS channel,
Set 1, 1, and 0 to KON _ASS and RE _ASS respectively. As a result, the ON event key in the UK is assigned to the ASS channel. After this step
Move to 60.

In step 60, KEY is transmitted on the TG26 ASS channel.
The key-on processing is performed so that the sound corresponding to the key code data is generated in the UK tone color. Then, the process returns to the routine of FIG.

On the other hand, when the result of the determination at step 54 is negative (N) (there is no free channel), the control variable j is set to 0 at step 62, and then the process proceeds to step 64.

In step 64, the calculation shown in the following equation is performed, and the calculation result (the number of semitones from the root) is registered in the register DE.
Put in G.

(KC _j + 12-ROOT). MOD. 12 In this formula, KC _j represents the key code value of the key code register KC _j corresponding to the j-th channel, and ROOT represents the value of the root register ROOT. This formula itself divides the calculation result in parentheses by 12. Indicates that the remainder is obtained by performing arithmetic (integer operation). Further, to add the 12 KC _j is to prevent from becoming negative value of (KC _j -ROOT).

As an example, if KC _j = 38 (D ₂ ) and ROOT = 0 (C), the calculation result of the above equation is 2, and this is set in DEG.

Next, at step 66, the dissonance degree data corresponding to the values of the registers TYPE and DEG is read from the table memory 24 and placed in the dissonance degree register DIS _j corresponding to the j-th channel. As in the above example, DEG = 2 and TYPE =
If it is 0 (major), the dissonance degree data of value 3 from FIG. 3 is set in DIS _j . After this, the process proceeds to step 68.

In step 68, it is determined whether the key-on flag KON _j corresponding to the j-th channel is 0 (key-off). This judgment result is transferred to step 70 if affirmative (Y), and sets the plus 4 to the value of DIS _j to DIS _j. this is,
This is because the priority in the case of key-off is increased as compared with the case of key-on as described with reference to FIG. 7. For example, DIS _j that was 3 becomes 7.

When the processing of step 70 is completed or when the determination result of step 68 is negative (N) (key-on), the routine proceeds to step 72, where UK /
It is determined whether the LK flag UL _j is 0 (LK). If this determination result is affirmative (Y), the process proceeds to step 74.

At step 74, DIS _j is set to -1. This is the step described later for the LK sound allocation channel.
This is to prevent allocation as shown at 82.

When the process of step 74 is completed or when the determination result of step 72 is negative (N) (it is UK), the value of j is incremented by 1 in step 76, and then the process proceeds to step 78.

In step 78, it is determined whether j is smaller than 12. Step 62
Then, when j = 0, the first time step 76 is reached, j =
Therefore, the determination result in step 78 is affirmative (Y), and the process returns to step 64. Then, the above processing is repeated until j = 12 (end of processing for 12 channels).

When j = 12, the determination result of step 78 is negative (N).
And move to step 80.

In step 80, the number of the channel that gives the maximum value among the _{DISs 0} to 11 is set in the register ASS. DI
Possible values of S ₀ to 11 are -1, 0 to 7 as described above.
For example, if DIS ₅ is 4 and the maximum value, 5 is set in ASS. After this, the process proceeds to step 82.

In step 82, it is determined whether the value of the dissonance degree register DIS _ASS corresponding to the ASS channel is -1. If the result of this determination is affirmative (Y), it means that all 12 channels were assigned channels of LK sound, and the routine returns to the routine of FIG. Therefore, in this case, the channel assignment of the on-event key in the UK is not performed.

If the determination result of step 82 is negative (N),
The value of DIS _ASS is one of 0 to 7, and the process proceeds to step 58. Here, the rank "2" in FIG.
The correspondence relationship between “5” and the value of DIS _ASS is as follows. Order DIS _ASS value 2 7, 6, 5 3 4 4 3, 2, 1 5 0 In step 58, the ON event key in the UK is assigned to the ASS channel as described above. Then, in step 60, the key-on processing of the assigned sound is performed on the ASS channel of the TG 26 as described above. After that, the process returns to the routine of FIG.

According to the above-mentioned processing, when there is no free channel, U
When there is a K key-on event, event key channels are assigned in the order of priority such as "2" to "5" shown in FIG. For example, _if the values of DIS ₀ to 11 are four types of 7, 4, 3, and 0, the event key is assigned to the channel having the maximum value of 7.

In addition, when there are a plurality of channels with dissonant sounds assigned (channels with ranks “2” or “4”), the channel with the highest degree of dissonance (lowest degree of consonance) is given priority for key assignment. receive. For example, DIS _0-11
If there are three types of values of 3, 2, and 1, the event key is assigned to the channel having the maximum value of 3.

Next, the determination result of step 52 is negative (N), L
The case of the K key-on event will be described.

In step 90, it is determined whether there is 1 in the flags RE ₀ to 11 (whether there is a release end channel),
If the determination result is affirmative (Y), the process proceeds to step 92.

In step 92, the number of the release end channel (empty channel) is set in the register ASS. Then, the process proceeds to step 94.

At step 94, the key code data of the register KEY is set in the key code register KC _ASS corresponding to the ASS channel, and the flag U corresponding to the ASS channel is set.
Set 0, 1, and 0 to L _ASS , KON _ASS , and RE _ASS respectively. Then, the process proceeds to step 96.

In step 96, KEY is sent on the TG26 ASS channel.
The key-on processing is performed so that the sound corresponding to the key code data of is produced in the LK tone color. Then, the process proceeds to step 98.

In step 98, a chord (root note and chord type) is detected based on the LK key-on one of KC ₀ to 11, and root note data and chord type data as chord information are placed in registers ROOT and TYPE, respectively. In this case, LK
It is key-on _can be detected by checking whether there is a 0 within the 1 there and _{UL 0 to 11} within a _{KON 0 to 11.} After that, the process returns to the routine of FIG.

On the other hand, when the determination result of step 90 is negative (N) (there is no free channel), the control variable j is set to 0 in step 100, and then the process proceeds to step 102.

In step 102, KC _j is performed in the same manner as in step 64 described above.
The number of semitones from the root of the root is calculated for the key code of, and this is put in the register DEG.

Next, in step 104, the discordance degree data corresponding to the values of TYPE and DEG is read from the table memory 24 and placed in DIS _j in the same manner as in step 66 described above. Then, the process proceeds to step 106.

In step 106, is the flag KON _j 1 (key on)?
Alternatively, it is determined whether the flag UL _j is 0 (LK). If the determination result is affirmative (Y), the process proceeds to step 108.

In step 108, DIS _j is set to -1. This is to prevent the channel being keyed on or the channel to which the LK sound is assigned from being assigned, as will be described later in step 120.

When the process of step 108 is completed, or the determination result of step 106 is negative (N) (it was a UK key-on).
In this case, the value of j is incremented by 1 in step 110, and then the process proceeds to step 112.

In step 112, j <1 as in step 78 described above.
It is determined whether or not 2, and if this determination result is affirmative (Y), the process returns to step 102. Then, the above-described processing is repeated until j = 12 (end of processing for 12 channels).

When j = 12, the determination result of step 112 becomes negative (N), and the routine proceeds to step 114.

In step 114, the number of the channel that gives the maximum value among the _{DISs 0} to 11 is set in ASS. in this case,
The possible values of DIS _0-11 are -1, 0-3.

Next, at step 118, it is determined whether there are five or more LK key-on channels, and the determination result is affirmative (Y).
If so, the routine returns to the routine of FIG. As a result,
Assignment of on-event keys in LK is limited to 4 keys or less.

If the determination result in step 118 is negative (N), the process proceeds to step 120 and it is determined whether DIS _ASS = -1 as in step 82 described above. If the result of this determination is affirmative (Y), it means that all of the 12 channels were the key-on channels or the channels assigned to the LK sound, and the routine returns to the routine of FIG. Therefore, in this case, channel assignment of the on-event key in LK is not performed.

If the determination result of step 120 is negative (N), it means that the value of DIS _ASS is any of 0 to 3, and the routine _proceeds to step 94. Here, the correspondence between the ranks “2” and “3” in FIG. 7 and the value of DIS _ASS is as follows. In order position DIS _ASS value 2 3,2 3 0 Step 94 assigns the ON event keys in LK to ASS channel in the same manner as described above. Then, in step 60, the key-on processing of the assigned sound is performed on the ASS channel of the TG 26 as described above. After this step
After the chord detection processing is executed by 98 in the same manner as described above, the routine returns to the routine of FIG.

According to the above-mentioned processing, if there is no free channel, L
When there is a K key-on event, event key channels are assigned in the order of priority such as "2" and "3" shown in FIG. When there are a plurality of channels, the channel with the highest degree of dissonance will be given priority for key assignment.

Next, the case of a key-off event in which the determination result in step 50 is negative (N) will be described.

In step 130, it is determined whether or not there is a key code that is the same as KEY in _KC0-11 . If the result of this determination is negative (N), it means that the key-off was unrelated to the sound being sounded, and the routine returns to the routine of FIG.

If the determination result of step 130 is affirmative (Y), the process proceeds to step 132, and the channel number with the same key code is set to the register OFF. Then, the process proceeds to step 134.

In step 134, the channel with the number indicated by OFF (O
Key-on flag KON _OFF corresponding to FF channel)
Set 0 to. Then, the process proceeds to step 136.

In step 136, a key-off process is performed to start the release of the sound being generated by the OFF channel of the TG 26.
As a result, the sound being sounded is gradually attenuated toward the release end. After this, the process proceeds to step 138.

In step 138, OFF channel compatible UK / LK
It is determined whether the flag UL _OFF is 0 (LK). If the determination result is negative (N), the routine returns to the routine shown in FIG. 5, but if the determination is positive (Y), the routine proceeds to step 98.

In step 98, chord detection processing is performed as described above. As a result, when the LK sound being sounded is keyed off,
The root note and chord type are detected based on the key depression state after the key-off, and are set to ROOT and TYPE, respectively.

Modifications The present invention is not limited to the above embodiments, but can be implemented in various modified forms. For example, the following changes are possible.

(1) UK and LK do not necessarily have to be two-stage keyboards,
The keyboard may be divided into a range of keys with a single-stage keyboard. Further, the pitch specifying means need not be a keyboard. For example, the pitch information may be automatically and sequentially output from the memory.

(2) The release end may be estimated from the key operation or the like (for example, a predetermined time from key-off) without being detected from the actual envelope.

(3) The chord detection may be performed at the release end instead of the key off, or may be performed only at the key on.

(4) Automatic accompaniment such as auto bass chord may be performed using the detected chord information.

(5) The determination of the degree of consonance is not limited to the embodiment, and, for example, it may be determined that only the same note as the LK key depression is a consonant tone and the other notes are dissonant tones. Alternatively, the degree of consonance may be determined directly from the actual key depression in LK without detecting the chord.

(6) The key assignments for UK and LK are not limited to the embodiment, and high temperature priority may be given. In short, it suffices to be able to distinguish the truncation order of consonant sounds and dissonant sounds.

(7) The tone generation channel is not common to UK and LK,
You may make it provide each for UK and LK for exclusive use.

[Effect of the Invention] As described above, according to the present invention, the dissonant sound is preferentially truncated, so that when the fast passage is played as a melody by improvisation, for example, a dissonant sound is generated. It has the effect of quickly disappearing and producing a beautiful chord-like performance sound.

Further, as shown in the embodiment, the pitch information may be assigned to the channel having the minimum degree of consonance by storing and appropriately reading the degree of consonance information corresponding to the pitch difference with respect to the root note for each chord type. For example, among the dissonant sounds, the ones with the highest dissonance are erased in order, which is very useful for the performance effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an electronic musical instrument according to an embodiment of the present invention, FIG. 2 is a diagram showing key code values for each pitch, and FIG. 3 is an example of contents stored in a table memory 24. FIG. 4, FIG. 4 is a diagram showing an example of an envelope waveform, FIG. 5 is a flowchart of a main routine, FIG. 6 is a flowchart of a release end interrupt routine, FIG. 7 is a diagram showing allocation priority, FIG. 8 is a flowchart showing a subroutine of key event processing. 10 ... bus, 12 ... upper keyboard, 14 ... lower keyboard, 16 ... switch group,
18 ... Central processing unit, 20 ... Program memory, 22 ... Register group, 24 ... Table memory, 26 ... Tone generator,
28 ... sound system.

Claims (2)

[Claims] 1. A pitch designating means capable of performing at least the first and second parts and generating pitch information according to the contents of each performance, and a sound source means having a plurality of musical tone generating channels, In an electronic musical instrument in which pitch information generated from the pitch designating means is assigned to an appropriate one of the plurality of tone generation channels to generate a tone, all of the plurality of tone generation channels are in use. In some cases, when new pitch information is generated from the pitch designating means, the degree of consonance of the performance sound of the second part with respect to the performance content of the second part is assigned to each tone generation channel to which the performance sound of the first part is assigned. And the tone generation channel with a relatively low degree of consonance is prioritized over the tone generation channel with a relatively high degree of consonance determined. Truncated apparatus characterized in that a assignment means for assigning the new pitch information thereto by. 2. A pitch designating means which has at least a first key area for playing a melody and a second key area for playing an accompaniment, and which generates pitch information according to performance contents in these key areas, and a plurality of pitch specifying means. In the electronic musical instrument having a tone generator having a tone generation channel, the tone pitch information generated from the tone pitch specifying means is assigned to an appropriate one of the plurality of tone generation channels to generate a tone, Storage means for storing consonance degree information corresponding to the pitch difference with respect to the root note for each chord type; chord detection means for detecting the chord type and the root note from the key depression state in the second key range; When new pitch information is generated from the pitch designating means when all of the tone generation channels are in use, the performance tone for each tone generation channel to which the performance tone in the first key range is assigned To the root sound of Reading means for reading the consonance degree information corresponding to the pitch difference and the detected chord type from the storage means, and the tone generation channel having the smallest consonance degree among the read consonance degree information is given priority to the new A truncation device, which is provided with an assigning means for assigning different pitch information.