Characteristics of modern music rhythms in the 20th century

1. Rhythm is free and changeable: a significant feature of 20th century modern music is the free and changeable rhythm. Compared with the regular rhythms in traditional music, the rhythms in modern music are more flexible, with no fixed patterns or laws, and can be changed and developed freely according to the composer's creative intentions.

2. Fuzzy and uncertain beats: In modern music, beats are often vague and uncertain. Traditional music has a clear form of beat, such as 4/4 beat or 3/4 beat, while the beat in modern music often changes and is not limited to a single form of beat, which makes the rhythm of music more complex and diversified.

3. No beat, no bar line: In modern music, sometimes there is no rhythm or no bar line. In traditional music, the bar line is used to delineate the structure and organization of the piece, but in modern music, this restriction is broken, and the performers can freely arrange the rhythm according to the want, making the music performance more free and diversified.