The primary feature that gives ‘spectral music’ its stylistic uniqueness within the field of art music is the blurring of the traditionally distinct roles of harmony and timbre, through the use of chords derived from the naturally occurring overtones of instrumental timbre (often referred to as timbre chords). Development of these chords typically occurs very gradually, meaning it is often difficult to perceive the overall form of a spectral work based on the progression through its constituent timbre chords. This approach contrasts with the traditional reliance in both art music and other Western music styles on perceivable pitch-based development as a primary means of providing musical tension and form. Composers of spectral music must re...