* The number of different notes, chords, and rhythms used
* The use of unusual or complex time signatures
* The use of dissonant or unexpected harmonies
* The use of complex melodic lines or counterpoint
* The use of unusual or extended instrumental techniques
Based on these factors, some genres of music that are often considered to be more complex include:
* Classical music
* Jazz
* Progressive rock
* Electronic music
* Experimental music
However, it is important to note that there is no one definitive list of the most complex genres of music, and there are many other genres that could also be considered complex. Ultimately, the complexity of a piece of music is a matter of opinion.