Dissonance is an aspect of tonality that exists when pitches in the harmony clash with one another, thus creating tension. The opposite of dissonance is consonance. Dissonance is not the clash of timbres like cymbals or loud dynamics. It is the pitches that are placed close together that create a feeling of being unsettled. In most music dissonance wants to resolve to consonance. It is the combination of these consonant/dissonant forces that creates harmonic progressions. In Jazz dissonance is often unresolved as the tonalities tend to feature more extended harmonies. Atonal music is music that often strives for as much dissonance as possible.