Breaking tonality and hail for dissonance. Running wild with rhythm and deconstruction of musical forms. nothing is forbidden and everybody can do it. Means of recording, sound production and possibilities are greater than ever, but audience are less enthusiastic than ever.

In the beginning of the 20th century, the tendency began in romanticism - breaking old forms and conventions - intensified. Arnold Schönberg created an atonal (non-tonal, without a tonic) style of composition, in which he completely cancels the frame of conventional keys. He creates the "twelve-tone" system, in which the musician sets a series of notes and bases his work on this series. The different parts are independent of each other and there is no restriction on dissonance between voices. Stravinsky, however, contributed novelties in fields of rhythm and the idea of many tonics (polytonality), and was considered an innovator in the area of structure. Other trends were creating a "dissonant counterpoint", a sort of baroque polyphony, yet totally permissive in writing rules.

In the second half of the century, there was a further general collapse of conventions. Numerous forms emerged, and every artist set himself his own style and artistic philosophy. Electronic music and elctroacoustic music, combining electronic equipment and synthesisers with acoustic instruments; minimalist music; aleatory music; and more.