Automatic key adjusting apparatus and method, and a recording medium

Patent metadata

Field	Value
Publication number	US-9384716-B2
Application number	US-201414175915-A
Country	US
Kind code	B2
Filing date	Feb 7, 2014
Priority date	Feb 7, 2014
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

An automatic key adjusting apparatus is provided, which determines keys on an input melody in real time and adjusts the determined keys in non real time to obtain accurate keys, thereby enhancing accuracy of placement of chords. The automatic key adjusting apparatus is provided with a keyboard for playing a melody of a musical piece. CPU judges keys on the melody in real time based on a history of pitches of the played melody of the musical piece, and adjusts the result of the key judgment in non real time after the melody of the musical piece is played.

First claim

What is claimed is:

1. An automatic key adjusting apparatus comprising:
a performance input unit for performing and sequentially inputting a melody of a musical piece;
a real-time key judging unit for judging a key of the melody of the musical piece, while a user is performing the melody of the musical piece with the performance input unit, based on a history of pitches of the melody of the musical piece sequentially input by the performance input unit; and
a non real-time key modifying unit for modifying the key decided by the real-time key judging unit after the user has finished the performance of the melody of the musical piece with the performance input unit.

2. The automatic key adjusting apparatus according to claim 1 , wherein the non real-time key modifying unit comprises:
a decided-key database representing a final pitch of the melody of the musical piece and a relationship between the final pitch of the melody of the musical piece and the key; and
a non real-time key judging unit for judging whether or not a key read from the decided-key database with respect to the final pitch of the melody accords with the key decided by the real-time key judging unit, and for determining that the key read from the decided-key database is a decided key, when it is determined that both the keys accord with each other.

3. The automatic key adjusting apparatus according to claim 2 , further comprising:
a cadence judging unit for reading a candidate key from the decided-key database, wherein the candidate key is most closely related to the final pitch of the melody of the musical piece, and for judging whether or not a provisional chord terminates so as to meet a cadence, wherein the provisional chord is provisionally placed to a final interval of the musical piece based on the candidate key, when the non real-time key judging unit determines that the key read from the decided-key database does not accord with the key decided by the real-time key judging unit; and
a decided-key judging unit for judging based on the result of the judgment made by the cadence judging unit, whether or not the candidate key is the decided key.

4. The automatic key adjusting apparatus according to claim 3 , wherein the decided-key judging unit comprises:
a verifying unit for verifying if the candidate key causes any inconsistency in the musical piece from beginning to end, when the cadence judging unit determines that the provisional chord terminates so as to meet the cadence, and for determining that the candidate key is the decided key, when it is decided that the candidate key causes no inconsistency.

5. The automatic key adjusting apparatus according to claim 4 , wherein the decided-key judging unit comprises:
a key placing unit for placing the decided key in an interval of the musical piece where no inconsistency exists, and placing the key decided by the real-time key judging unit in the musical piece excluding the above interval, when the verifying unit determines that the candidate key causes an inconsistency; and
a modulation judging unit for judging whether a relationship between the key placed in a beginning interval of the musical piece and the key placed at an interval other than the beginning interval of the musical piece is ascending or not, and for determining that both the key placed in the beginning interval and the key placed in the other interval are the decided keys, when it is determined that the relationship between the keys is ascending.

6. The automatic key adjusting apparatus according to claim 1 , further comprising:
a relative key and borrowing chord database representing relationships between relative keys and borrowing chords;
wherein when plural keys are placed in the musical piece and an interval of the musical piece exists, where a not-verified key is placed, and a chord not in a relative key of the not-verified key is found in the interval, then it is decided that the not-verified key is the decided key.

7. The automatic key adjusting apparatus according to claim 1 , wherein the real-time key judging unit comprises:
a storing unit having a register for storing, at least, tone names, tone-name groups corresponding to a history of the input melody of the musical piece, and candidate keys, based on information input by the performance input unit, and a first table storing diatonic scale notes in each key; and
a key deciding unit for comparing the tone-name group corresponding to the history of the input melody of the musical piece with the first table to judge whether or not all the tone names contained in the history of the input melody of the musical piece are involved in a diatonic scale in some key, thereby narrowing a range of the candidate keys to be employed, thereby deciding a key for the musical piece, and storing the decided key in the register.

8. The automatic key adjusting apparatus according to claim 7 , wherein the key deciding unit judges whether or not a tritone and a scale note lying among the tritone involved in the diatonic scale in the candidate key are contained in the tone-name group corresponding to the history of the input melody of the musical piece, thereby furthermore narrowing the range of the candidate keys to be employed, when plural candidate keys are left as a result of narrowing the range of the candidate keys.

9. The automatic key adjusting apparatus according to claim 7 , wherein the key deciding unit determines that a key having a least number of key signatures is the key for the musical piece, when plural candidate keys are left as a result of narrowing the range of the candidate keys.

10. The automatic key adjusting apparatus according to claim 7 , wherein the storing unit has a second table storing key-unique tritones and scale notes lying between the tritone among diatonic scale notes in each key; and
the key deciding unit compares the tone-name group corresponding to the history of the input melody of the musical piece with the second table to judge whether or not tone names contained in the history of the melody of the musical piece accord with the tritone and the scale note in some key, thereby narrowing the range of the candidate keys to be employed, and decides a key to be employed for the musical piece, storing the decided key in the register.

11. The automatic key adjusting apparatus according to claim 7 , wherein, when the range of the candidate keys has been narrowed down into one candidate key, the key deciding unit determines that such one candidate key is the decided key, storing said decided key in the register, and when the range of the candidate keys has not been narrowed down into one candidate key, the key deciding unit determines that a predetermined candidate key is a provisional key, storing the provisional key in the register.

12. The automatic key adjusting apparatus according to claim 7 , further comprising:
a chord-name judging unit for deciding a current chord name based on the pitches corresponding to the melody of the musical piece and a previous chord name, and
wherein, when the current chord name has a predetermined relationship with the key stored in the register, the key deciding unit obtains a new key based on the predetermined relationship between the current chord name and the key stored in the register.

13. The automatic key adjusting apparatus according to claim 12 , wherein, when the current chord name is a chord of 7 having a relationship other than III7 or V7 in the key stored in the register, the key deciding unit calculates a difference between the key and a root tone of the current chord name, and adds the calculated difference and a semitone to the key to obtain

Assignees

• Casio Computer Co Ltd

Inventors

• Okuda Hiroko

Classifications

• G10H1/0008 Primary

  Associated control or indicating means · CPC title

• G10H2210/005

  Musical accompaniment, i.e. complete instrumental rhythm synthesis added to a performed melody, e.g. as output by drum machines · CPC title

• G10H1/42

  comprising tone forming circuits · CPC title

• G10H2210/576

  Chord progression · CPC title

• G10H2210/331

  Note pitch correction, i.e. modifying a note pitch or replacing it by the closest one in a given scale · CPC title