Abstract: An apparatus for producing a chord progression by connecting or chaining chord patterns. In a preferred embodiment, the apparatus includes as a source of musical knowledge, a database of musical structure of various music pieces and a database of chord patterns. In operation, from the musical structure database, a multi-leveled structural feature of a music piece is selected and determined level by level, either automatically, semi-automatically, or manually, through a dialogue conducted between the apparatus and the user. Thereafter, chord patterns are chosen one at a time from the chord pattern database in a similar dialogue manner. A concatenating module controls the concatenation of the chosen chord patterns to be commensurate with the characteristic musical structure previously determined, thereby to provide a chord progression with musicality, naturalness and well-balanced unity and variety.

Abstract: A system for automatically determining principal tones of an accompaniment line supporting a melodic line comprises a plurality of principal tone inference engines which after principal tones in accordance with different rules of inference from one another and a priority control which controls priorities among the plurality of inference engines to determine final principal tones in the accompaniment line. Each principal tone inference engine may include a condition checker which checks to see whether musical conditions are met and a principal tone generator which generates principal tones. The priority control monitors the information supplied from the condition checkers to select final principal tones supplied from the principal tone generators. Some of the final principal tones may be dependent from the preceding principal tone while some others may be independent. There may be also be provided a storage of the structure of music which is reflected in a series of the final principal tones.

Abstract: An envelope extracting circuit extracts an envelope from the waveform sampled by a musical tone sampling circuit, and stores the envelope data into a memory. An envelope approximating circuit approximates the envelope data as stored in the memory by the function data such as linear or exponential function data. The original envelope is approximated by a limited number of function waveforms whose characteristics change at switching points.

Abstract: A system for automatically determining principal tones of an accompaniment line supporting a melodic line comprises a plurality of principal tone inference engines which infer principal tones in accordance with different rules of inference from one another and a priority control which controls priorities among the plurality of inference engines to determine final principal tones in the accompaniment line. Each principal tone inference engine may include a condition checker which checks to see whether muscial conditions are met and a principal tone generator which generates principal tones. The priority control monitors the information supplied from the condition checkers to select final principal tones supplied from the principal tone generators. Some of the final principal tones may be dependent from the preceding principal tone while some others may be independent. There may also be provided a storage of the structure of music which is reflected in a series of the final principal tones.