US 8,802,956 B2Granted

Automatic accompaniment apparatus for electronic keyboard musical instrument and fractional chord determination apparatus used in the same

AssigneeKabushiki Kaisha Kawai Gakki Seisakusho

InventorsYoshifumi Kira, Kiyomi Kurebayashi

Life of this patent

Estimating the term…

Abstract

The number of chords belonging to a first chord group is decreased to less than the number of chords belonging to a second chord group. In a first detection mode, when a first determining unit determines that a state of key depressed does not correspond to any chord in a first chord group, a previously selected chord is continuously determined. Accordingly, even if a chord detection is performed on a change of melody point by point, the number of chords substantially detected is decreased. This decreases the number of changes in accompaniment, thus stabilizing a playback of the accompaniment.

Claims8

Dependent claims

An automatic accompaniment apparatus for an electronic keyboard musical instrument for performing chord detection based on a state of a key depressed in a region combining at least an accompaniment region and a melody playing region in a keyboard with a plurality of keys, so as to perform automatic accompaniment based on a detected chord, the automatic accompaniment apparatus, comprising:

setting unit configured to set a detection mode by switching between a first detection mode and a second detection mode, the first detection mode setting a whole region combining the accompaniment region and the melody playing region to a detected object of the chord detection, the second detection mode setting a part of the accompaniment region to a detected object of the chord detection;
first determining unit configured to determine whether or not a state of a key depressed in a region set to the detected object corresponds to any chord in a first chord group in a case where the first detection mode is set by the setting unit;
first selecting unit configured to select a corresponding chord in the first chord group in a case where the first determining unit determines that the state of the key depressed corresponds to one chord in the first chord group;
second determining unit configured to determine whether or not the state of the key depressed in the region set to the detected object corresponds to any chord in a second chord group in a case where the second detection mode is set by the setting unit;
second selecting unit configured to select a corresponding chord in the second chord group in a case where the second determining unit determines that the state of the key depressed corresponds to one chord in the second chord group;
and
automatic accompaniment unit configured to perform automatic accompaniment based on a chord selected by the first selecting unit or the second selecting unit, wherein
in a case where the number of chords belonging to the first chord group is set to be fewer than the number of chords belonging to the second chord group, and the setting unit sets the first detection mode, a previously selected chord is continuously determined when the first determining unit determines that the state of the key depressed is not any chord in the first chord group.

5 more elements

A fractional chord determination apparatus for determining a fractional chord corresponding to a depressed key, by setting a first region to detect a bass root of the fractional chord on a keyboard with a plurality of keys and a second region to detect a chord with a root that is different from the bass root on the keyboard, so as to determine the fractional chord by detecting the bass root and the chord corresponding to a state of a key depressed in each region, the fractional chord determination apparatus comprising:

first setting unit configured to set the first region corresponding to a lowest-pitched sound by a key depressed on the keyboard;
determining unit configured to determine whether the fractional chord is to be determined corresponding to the number of keys depressed in the first region;
second setting unit configured to set a region between:
a lower limit sound set corresponding to a lowest-pitched sound by the key depressed on the keyboard;
and an upper limit sound set corresponding to a lowest-pitched sound by the key depressed on a keyboard of a higher sound than a sound in the first region, to the second region when the determining unit determines that the fractional chord is to be determined;
and
control unit configured to respectively determine:
a bass root based on the state of the key depressed in the first region, and a chord with a root that is different from the bass root based on the state of the key depressed in the second region, and for performing automatic accompaniment corresponding to the fractional chord.

5 more elements

first setting unit configured to set the first region corresponding to a lowest-pitched sound by a key depressed on the keyboard to a sound between the lowest-pitched sound and a sound higher than the lowest-pitched sound by a pitch corresponding to N1 key shown in the following formula 9;
determining unit configured to determine that the fractional chord is to be determined in a case where the number of depressions on the keyboard in the first region is equal to or less than two, and for determining that the fractional chord is not to be determined in a case where the number of depressions is equal to or more than three;
second setting unit configured to set a region between:
a lower limit sound that is a sound higher than the lowest-pitched sound upon a key depressed on the keyboard by a pitch corresponding to the N2 key shown in the following formula 10;
and an upper limit sound that is a sound higher than the lowest-pitched sound upon a key depressed on a keyboard of a higher sound than a sound in the first region by a pitch corresponding to the N3 key shown in the following formula 11, to the second region when the determining unit determines that the fractional chord is to be determined;
and
control unit configured to respectively determine:
a bass root based on a state of depressed key in the first region, and a chord with a root that is different from the bass root based on a state of key depressed in the second region, and for performing automatic accompaniment corresponding to the fractional chord
1<N1 (Formula 9)
1<N2 (Formula 10)
1<N3 (Formula 11).

8 more elements

Dependencies are inferred from the claim text.

patentgrep

Loading patent…

Abstract

setting unit configured to set a detection mode by switching between a first detection mode and a second detection mode, the first detection mode setting a whole region combining the accompaniment region and the melody playing region to a detected object of the chord detection, the second detection mode setting a part of the accompaniment region to a detected object of the chord detection;
first determining unit configured to determine whether or not a state of a key depressed in a region set to the detected object corresponds to any chord in a first chord group in a case where the first detection mode is set by the setting unit;
first selecting unit configured to select a corresponding chord in the first chord group in a case where the first determining unit determines that the state of the key depressed corresponds to one chord in the first chord group;
second determining unit configured to determine whether or not the state of the key depressed in the region set to the detected object corresponds to any chord in a second chord group in a case where the second detection mode is set by the setting unit;
second selecting unit configured to select a corresponding chord in the second chord group in a case where the second determining unit determines that the state of the key depressed corresponds to one chord in the second chord group;
and
automatic accompaniment unit configured to perform automatic accompaniment based on a chord selected by the first selecting unit or the second selecting unit, wherein
in a case where the number of chords belonging to the first chord group is set to be fewer than the number of chords belonging to the second chord group, and the setting unit sets the first detection mode, a previously selected chord is continuously determined when the first determining unit determines that the state of the key depressed is not any chord in the first chord group.

5 more elements