JPH09319365A - Pitch detecting device for string instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a string instrument pitch detecting device capable of improving the accuracy and speed of pitch detection immediately after note-on. SOLUTION: When an ultrasonic pulse outputted from an ultrasonic pulse output part 21 in an ultrasonic wave sensor 1 and reflected by a player's hand is detected by an ultrasonic pulse detection part 22, a distance information converting part 31 converts a time interval from the output of the pulse up to its detection into the information of a finger plate operating position and a coefficient generating part 34 retrieves a coefficient table stored in a table data storing part 38 in each string, sets up the retrieved result in a filter 33, retrieves a candidate sound table in the storing part 38 in each string, and sends a candidate sound to a music instrument digital interface(MIDI) signal generating part 37. The MIDI signal generating part 37 compares the pitch of a musical sound detected, band-limited and detected at its pitch with the candidate sound, and when the musical sound pitch is included in the candidate sound, sends an MIDI signal corresponding to the pitch to a sound source 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pitch detecting device for a stringed musical instrument, which detects a pitch of a musical tone based on an inputted musical tone signal, particularly a musical tone signal inputted from a string of a stringed musical instrument.

[0002]

2. Description of the Related Art Conventionally, as a pitch detecting device for a stringed instrument,
A special pickup that detects the string vibration of each string is added to a normal string instrument (since this guitar is generally a "guitar", the explanation will be limited to "guitar"). It is known to detect the pitch of a musical tone based on the generated musical tone signal. There is a so-called guitar synthesizer that generates a musical sound (usually a musical sound having a tone color other than the tone color of a guitar) according to the pitch thus detected.

As described above, the current guitar synthesizer is mainly constructed by adding a dedicated pickup to a normal guitar. This is because it is possible to meet a wide range of demands of the guitar player by making it possible to select the performance based on the pitch-detected musical sound and the performance by the normal guitar playing method.

Further, it is difficult to detect the pitch of a musical sound generated by playing a guitar, as compared with the pitch detection of a musical sound generated by playing another musical instrument such as a piano. It directly detects which key is pressed by the piano,
This is because the pitch is specified by this, whereas in a stringed instrument, the pitch is obtained by picking up the vibration of the string due to the consonant string with a pickup and calculating the cycle of the vibration. In order to make this pitch detection as easy as possible, a filter for limiting the frequency band of the signal detected from the pickup is provided, and the pitch of the musical tone is detected based on the signal whose frequency band is limited by the filter.
Further, as such a filter, a filter whose filter characteristic (specifically, filter coefficient) can be changed is used.
It is also known that the filter characteristics are changed according to the information after pitch detection to further improve the accuracy of pitch detection.

[0005]

However, in the above-mentioned conventional pitch detecting device for a stringed instrument, since the filter characteristic is changed according to the information after the pitch detection, it is possible to improve the accuracy of the pitch detection immediately after the note-on. I couldn't. Generally, the most accurate pitch detection is to be performed immediately after the note-on, and the conventional pitch detection device for a stringed instrument cannot meet such a request.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a pitch detection device for a stringed instrument that can improve the accuracy and speed of pitch detection immediately after note-on.

[0007]

In order to achieve the above object, the present invention provides a fingerboard operation position detecting means for detecting a fingerboard operation position of a player in a stringed instrument, and a musical sound estimated to be generated by the player. Candidate pitch determining means for determining a pitch candidate based on the detected fingerboard operation position, musical tone pitch detecting means for detecting a pitch of a musical tone generated by the player, and the determined candidate tone When there is a pitch corresponding to the detected musical tone pitch in the high pitch, the musical tone pitch recognizing means for certifying the detected musical tone pitch as the musical tone pitch generated by the player.

[0008] Further, preferably, a filter means provided before the tone pitch detecting means for filtering a signal inputted to the pitch detecting means with a predetermined characteristic,
And a filter characteristic change control means for changing and controlling the characteristic of the filter means based on the fingerboard operation position detected by the fingerboard operation position detection means.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a guitar synthesizer to which a pitch detecting device for a stringed instrument according to an embodiment of the present invention is applied.

In the figure, the guitar synthesizer according to the present embodiment includes, for example, a pickup 1 for independently detecting the string vibration of each string of a 6-string guitar G and converting it into an electric signal, and a player (guitar player). Ultrasonic sensor 2 for detecting the fingerboard (FB) operating position
And the pitch of the musical sound generated by the string vibration based on the outputs from the pickup 1 and the ultrasonic sensor 2, and the MIDI (Musical Instrument) corresponding to the detected pitch is detected.
ment Digital Interface) signal (code), a sound source 4 for converting the MIDI signal output from the control unit 3 into a tone signal, and a tone signal from the tone source 4 converted into sound, for example, a speaker or the like. Sound system 5
It is composed of

The ultrasonic sensor 2 includes an ultrasonic pulse output section 21 for outputting an ultrasonic pulse and an ultrasonic wave for detecting a reflected pulse reflected by an obstacle (mainly the player's hand F). It is composed of a pulse detector 22.

The control unit 3 outputs pulses from the ultrasonic pulse output unit 21 and six A / D converters 30 for converting the analog musical tone signals output from the pickup 1 into digital musical tone signals. To ultrasonic pulse detector 2
In step 2, the time until the reflection pulse is detected is measured, and the player's fingerboard operation position is detected based on the measurement result. That is, a distance information conversion unit 31 that converts time information into distance information, a tuning information storage unit 32 that stores this tuning information when the performer performs irregular tuning, and an output from the A / D converter 30. The six filters 33 that independently limit the frequency band of each of the digital tone signals that have been generated, and the filters 33 according to the output result (information about the fingerboard operation position of the performer) from the distance information conversion unit 31. A coefficient generating unit 34 that generates each filter coefficient and sets each filter coefficient in the corresponding filter 33, and six pitch detections that detect the tone pitch of each string from the tone signal output from the filter 33 and having a limited frequency band. Section 35, six envelope detecting sections 36 for detecting the envelopes of the respective tone signals output from the A / D converter 30, and the pitch. The pitch and envelope for each string output from the output unit 35 and the envelope detection unit 36, the distance information about the player's fingerboard operating position output from the distance information conversion unit 31, and the tuning output from the tuning information storage unit 32. M based on information
A MIDI signal generation unit 37 that generates an IDI signal, a coefficient table that the coefficient generation unit 34 refers to when generating a filter coefficient, a candidate sound table and various tables that the MIDI signal generation unit 37 uses when generating a MIDI signal. And the like, and a table data storage unit 38 for storing the above.

FIG. 2 is a diagram showing an example of a selection method for selecting a candidate sound from the candidate sound table stored in the table data storage unit 38.

In the figure, FB indicates a fingerboard of the guitar G, and a plurality of frets f are arranged on the fingerboard FB.
Six strings s are stretched. The regions r between the adjacent frets f and f are numbered sequentially from "1", and the part of each chord s divided by each fret is:
A key code corresponding to a musical sound generated when the player presses the portion is described. In the example shown in the figure, the key code of the musical tone generated when normal tuning is performed is described. This key code is one in which the key codes stored in the candidate sound table are arranged on the fingerboard FB for easy visual understanding. In the actual candidate sound table, each key code corresponds to the fingerboard operation position. Is stored as a parameter for each string.

In the figure, an arrow 41 indicates the position of the player's hand calculated based on the output from the distance information conversion unit 31, and when the position of the player's hand is the position of the arrow 41, the candidate is selected. As the sound, for example, the key code in the circle 42, that is, four key codes for each string s are selected.

The key code selected in this way is
As will be described later with reference to FIG. 5, the MIDI signal generator 37
And is stored in a candidate sound register (not shown).

Note that the player sometimes plays without operating the fingerboard FB, and such a case is referred to as "open string".

The operation process of the guitar synthesizer configured as described above will be described below with reference to FIGS.

FIG. 3 is a flow chart showing the procedure of a main routine executed by the control section 3 of the guitar synthesizer of this embodiment, particularly the MIDI signal generating section 37.

In the figure, first, it is judged whether or not the operation mode is the "tuning mode" (step S).
1). In the present embodiment, the operation modes are roughly classified into two types, that is, a "playing mode" and a "tuning mode". The "playing mode" mainly refers to a pitch from a musical tone signal detected by the pickup 1. Detect and M
The mode in which the process of generating the IDI signal is performed, and the "tuning mode" is the mode in which the irregular tuning can be performed as described above.

If it is determined in step S1 that the operation mode is the "tuning mode", the process proceeds to step S2. If the performer makes a tuning different from normal tuning such as irregular tuning, tuning information for the tuning is displayed. After setting, that is, storing in the tuning information storage unit 32, step S1
Return to

On the other hand, when it is determined in step S1 that the operation mode is not the "tuning mode", that is, the "playing mode", the process proceeds to step S3, and it is determined whether or not there is a note-on. Here, the determination as to whether or not the note is on is performed by determining whether or not the level of the tone signal output from the envelope detection unit 36 has become larger than a predetermined threshold value.

FIG. 4 is a diagram showing an example of a musical tone signal waveform of a certain string detected by the pickup 1, in which the vertical axis represents the signal level and the horizontal axis represents the time. As shown in the figure, when the detected musical tone signal exceeds the signal level TH, that is, when time t0 is reached, it is determined that note-on has occurred.

When it is determined in step S3 that note-on is detected, the MIDI signal generator 3 stores the processing state of the tone signal detected by the pickup 1.
"1" is stored in the processing state storage area E_i secured at a predetermined position of the RAM (not shown) of No. 7. Where i is
The number of the string relating to the detected note-on is shown, and in the present embodiment, it corresponds to any integer value of 1 to 6.
Further, an integer value of 0 to 2 is stored in the processing state storage area E_i, "0" indicates a note-off state, and "1" indicates that a note-on has been detected but a MIDI signal is output. A state in which no note-on is detected and "2" indicates that note-on is detected and a MIDI signal is output (during note-on).

On the other hand, if it is determined in step S3 that no note-on is detected, step S4 is skipped and the process proceeds to step S5.

In step S5, it is determined whether or not the pitch has been detected. The pitch detecting method will be described below with reference to FIG.

The tone pitch is calculated based on the time between the points (zero cross points) where the tone signal crosses the signal level "0". There are two types of zero-cross points, that is, when the tone signal level changes from the negative side to the positive side and crosses "0", and vice versa. Pitch detection is the time between zero-cross points of the same type. Is calculated based on. Specifically, in FIG. 4, time t1-t3, time t1-
The pitch is detected based on any one of the time t5, the time t2-t4, and the time t2-t6.

After the note-on is detected, that is, when the pitch is detected based on the zero-cross point after time t0, the time from time t2-t4 or time t2-.
The pitch will be detected based on any of the times of t6.

When the pitch is detected in the determination in step S5, it is detected whether or not the value of the processing state storage area E_j corresponding to the detected string j is "1", that is, the note-on is detected. Determines whether or not the MIDI signal is not being output (step S6).

If it is determined in step S6 that E_j ≠ 1, the process proceeds to step S7, and the string j is in the note-on state (E_j
= 2), the difference corresponding to the pitch change, that is, the difference between the pitch currently being output and the pitch corresponding to the change is M as pitch bend information.
Generates and outputs an IDI signal.

On the other hand, in the determination of step S6, E_j = 1
If so, the process proceeds to step S8, and it is determined whether or not there is a candidate pitch (candidate sound) for the string j, that is, the candidate sound stored in the register corresponding to the string j of the candidate sound register corresponds to the detected pitch. Determine whether. Specifically, assuming that the string j is "6" and the player's hand is at the position of the arrow 41 in FIG.
"5F #", "5G", "5G #", and "5A" are selected from the candidate tone table and stored in the candidate tone register, some of which correspond to the pitch detected in step S5. It is determined whether or not.

At this time, a plurality of pitches may be detected. In the example of FIG. 4, the case where two pitches, that is, the time-based pitch from time t1 to t3 and the time-based pitch from time t1 to t5 are detected corresponds to this. In such a case, it is necessary to select only one of them, but when the number of candidate sounds is four as described above, one of the reference candidate sounds is selected and the selected candidate sound is selected. Ratio of the cycle of the sound and the cycle of the detected pitch (time between zero cross points) (cycle of detected pitch / cycle of selected candidate sound)
Is less than or equal to a predetermined value (for example, "0.84"), the detection pitches that are less than "0.84" are excluded, and adopt.

If it is determined in step S8 that the detected pitch is among the candidate pitches for the string j, a MIDI signal (note-on and key code) corresponding to the pitch is generated and output (step S9), "2" is set in the processing state storage area E_j (step S10).

On the other hand, if it is determined in step S8 that there is no detected pitch among the candidate pitches for the string j,
It is determined whether or not this state has occurred a predetermined number of times (for example, three times) continuously (step S11).

If it is determined in step S11 that this state has occurred a predetermined number of times in succession, the pitch detection processing (logic) according to the candidate pitch, which is a feature of the present invention, is ignored.
The pitch is detected by a normal pitch detection process, that is, a process of detecting the pitch only from the time between the zero-cross points (step S12), and the process proceeds to step S9 to generate a MIDI signal according to the detected pitch.

On the other hand, if it is determined in step S11 that this state has not occurred for a predetermined number of times in succession, step S1
Go to 3.

In step S13, it is determined whether or not note-off is detected. This determination is based on the above step S3.
In the same way as the note-on judgment of, a predetermined threshold value is compared, and when the level below this threshold value continues for a predetermined time,
It may be determined to be note-off.

If a note-off is detected in the determination in step S13, the MIDI corresponding to the note-off is detected.
A signal (note-off and key code) is generated and output (step S14), "0" is set in the processing state storage area E_k corresponding to the string k related to note-off, and then the process returns to step S1 and the above-mentioned The process of is repeated.

FIG. 5 is a flow chart showing the procedure of an interrupt process executed by the control unit 3. This process is performed in response to a timer interrupt generated every time a timer (not shown) measures a predetermined time (for example, 10 msec). Is executed.

In the figure, first, a scanning process of the fingerboard operation position of the performer is performed (step S21). Specifically, after the ultrasonic pulse output unit 21 of the ultrasonic sensor 2 outputs the ultrasonic pulse, the reflected pulse is detected by the ultrasonic pulse detection unit 22 and the time from the output to the detection is timed. . Then, the player's fingerboard operation position is detected based on this time count.

Next, as a result of the scanning process in step S21, it is determined whether or not the fingerboard operating position has been changed (step S22). When the fingerboard operating position is not changed, the main interrupt process is immediately terminated, while When the fingerboard operating position is changed, the process proceeds to step S23.

In step S23, the tuning information stored in the tuning information storage unit 32 and a plurality of possible pitches (key chords) for each string from the changed fingerboard operating position (in the present embodiment, in the present embodiment). , As mentioned above, 4
,) From the candidate sound table in the table data storage unit 38.

In a succeeding step S24, the plurality of searched pitches (candidate sounds) for each string are sent to the MIDI signal generator 37. As a result, the candidate sound is stored in the candidate sound register of the MIDI signal generator 37.

In the following step S25, step S23
Similarly, the filter coefficient for each string is searched from the coefficient table of the table data storage unit 38 according to the tuning information and the fingerboard operation position, and the filter coefficient searched for each string is sent to the corresponding filter 33. Did (step S
26) After this, this interruption processing is ended.

As described above, in this embodiment, the fingerboard operation position of the player is detected, and the musical tone signal detected by the pickup 1 is detected based on the candidate sound determined according to the fingerboard operation position. Since the pitch is determined, the accuracy and speed of pitch detection can be improved, and thus the operability of real-time performance and real-time recording of performance data generated by the performance can be improved.

Further, since the characteristic of the filter 33 is changed according to the detected fingerboard operation position, only the fundamental wave of the pitch to be detected can be detected, and its overtone component can be effectively removed. Thereby, the accuracy of pitch detection can be further improved. Since this filter characteristic is changed before the note-on is detected, the pitch detection at the note-on can be accurately performed.

In this embodiment, the ultrasonic sensor 2 is used to detect the fingerboard operation position of the player.
Not limited to this, for example, the position at which the fret f is in contact with the string s by detecting an electric current flowing through the string s, the position detected by an optical detection method, or the fingerboard operation position of the player is detected. Any method may be used as long as it can detect Further, a change in voltage, a piezoelectric sensor, etc. can also be adopted.

In the present embodiment, the range for selecting candidate sounds is fixed to a preset range, but the present invention is not limited to this and the range may be changed by the performer. At this time, setting may be made for each string. Further, this range may be changed according to the fingerboard operation position of the player. For example, when the fingerboard operation position is at the high position, the range of the candidate sounds is expanded, that is, the number of candidate sounds is increased, so that the detection accuracy at the high position where a pitch error is often detected can be improved. . Further, the player may be allowed to select whether or not to always include an open string in the candidate sound.

[0050]

As described above, according to the present invention,
When there is a pitch corresponding to the musical tone pitch detected by the musical tone pitch detecting means in the candidate pitches determined based on the fingerboard operating position detected by the fingerboard operating position detecting means, the detected musical tone pitch is detected. Since it is identified as the musical tone pitch generated by the player, the pitch detection accuracy and speed can be improved.

Further, since the characteristic of the filter means is controlled to be changed based on the fingerboard operation position detected by the fingerboard operation position detecting means, the pitch detection accuracy can be further improved and immediately after the note-on. The accuracy and speed of pitch detection can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a guitar synthesizer to which a pitch detection device for a stringed instrument according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing an example of a selection method for selecting a candidate sound from the candidate sound table data of FIG.

FIG. 3 is a flowchart showing a procedure of operation processing executed by a control unit of FIG. 1, particularly a MIDI signal generation unit.

4 is a diagram showing an example of a musical tone signal waveform of a certain string detected by the pickup of FIG.

FIG. 5 is a flowchart showing a procedure of interrupt processing.

[Explanation of symbols]

2 Ultrasonic sensor (fingerboard operation position detection means) 31 Distance information conversion part (fingerboard operation position detection means) 33 Filter (filter means) 34 Coefficient generation part (filter characteristic change control means) 35 Pitch detection part (tone pitch detection) 37) MIDI signal generator (candidate pitch determining means, musical pitch determining means) 38 table data storage (candidate pitch determining means, filter characteristic change controlling means)

Claims (2)

[Claims] 1. A fingerboard operation position detecting means for detecting a fingerboard operation position of a player in a stringed instrument, and a pitch candidate of a musical tone estimated to be generated by the player,
Candidate pitch determining means for making a decision based on the detected fingerboard operation position, musical tone pitch detecting means for detecting a pitch of a musical tone generated by a player, and the detected pitch during the decided candidate pitch. A pitch detecting device for a stringed instrument, comprising: a musical tone pitch recognizing means for certifying the detected musical tone pitch as a musical tone pitch generated by a player when there is a pitch corresponding to the musical tone pitch. 2. Filter means provided in the preceding stage of the musical tone pitch detecting means for filtering a signal input to the pitch detecting means with a predetermined characteristic, and fingerboard operation detected by the fingerboard operating position detecting means. 2. The pitch detecting device for a stringed instrument according to claim 1, further comprising: filter characteristic change control means for changing and controlling the characteristic of the filter means based on the position.