What is atonal key?

Atonal key refers to a musical composition or passage that lacks a clear tonal center or key signature. In atonal music, traditional harmonic structures and scales are disregarded, leading to the use of all twelve tones of the chromatic scale without establishing a hierarchy among them. This results in a sound that is often perceived as dissonant or lacking resolution, creating a unique listening experience distinct from tonal music. Atonality is commonly associated with 20th-century composers like Arnold Schoenberg.