Computer-based systems, devices, and methods for generating aesthetic chord progressions and key modulations in musical compositions
Computer-based systems, devices, and methods for automatically generating aesthetic chord progressions and key modulations in musical compositions are described. Known harmonic relationships are expanded upon to produce a much richer set of harmonic transition probability models compared to conventional music theory, and these models are leveraged by a computer-based musical composition system to generate new musical compositions and variations of existing musical compositions. Techniques for enabling a computer-based musical composition system to automatically determine when to introduce a key modulation, what key to module to, and what chord progression(s) to use within the new key are all described.
1. A computer-implemented method of operating a computer-based musical composition system to generate a variation of a musical composition, wherein the variation includes a key modulation, the method comprising:
segmenting, by the computer-based musical composition system, the musical composition into segments;
performing, by the computer-based musical composition system, an automated clustering of the segments to group segments that are similar together;
solving, by the computer-based musical composition system, a constraint satisfaction problem that specifies that:
every segment is assigned a key;
segments in a same cluster are assigned a same key; and
segments that abut one another are assigned respective keys that conform to an allowed key to key transition with respect to a key progression generation model, wherein at least one pair of abutting segments is assigned a key to key transition that is different from a corresponding key to key transition in the musical composition; and
generating a variation of the musical composition that satisfies the constraint satisfaction problem.
2. The method of claim 1 wherein solving, by the computer-based musical composition system, a constraint satisfaction problem that specifies that segments that abut one another are assigned respective keys that conform to an allowed key to key transition with respect to a key progression generation model includes solving, by the computer-based musical composition system, a constraint satisfaction problem that specifies that segments that abut one another are assigned respective keys that are edge-connected in a representation of a graph wherein each node of the graph corresponds to a respective key and each edge of the graph corresponds to a respective transition between a respective pair of keys.
3. The method of claim 1 wherein solving, by the computer-based musical composition system, a constraint satisfaction problem that specifies that segments that abut one another are assigned respective keys that conform to an allowed key to key transition with respect to a key progression generation model includes solving, by the computer-based musical composition system, a constraint satisfaction problem that specifies that segments that abut one another are assigned respective keys that share a pivot chord relationship.
4. The method of claim 1 wherein solving, by the computer-based musical composition system, a constraint satisfaction problem that specifies that segments that abut one another are assigned respective keys that conform to an allowed key to key transition with respect to a key progression generation model includes solving, by the computer-based musical composition system, a constraint satisfaction problem that specifies that segments that abut one another are assigned respective keys that share a common chord.