<Li> Coincidence of partials: with consonance being a greater coincidence of partials (Helmholtz & 1954 (1877),). By this definition, consonance is dependent not only on the width of the interval between two notes (i.e., the musical tuning), but also on the combined spectral distribution and thus sound quality (i.e., the timbre) of the notes (see the entry under critical band). Thus, a note and the note one octave higher are highly consonant because the partials of the higher note are also partials of the lower note (Roederer 1995, p. 165). Although Helmholtz's work focused almost exclusively on harmonic timbres and also the tunings, subsequent work has generalized his findings to embrace non-harmonic tunings and timbres (Sethares 1992; Sethares 2005; Milne, Sethares, and Plamondon 2007,; Milne, Sethares, and Plamondon 2008,; Sethares et al. 2009,). </Li> <Li> Fusion: perception of unity or tonal fusion between two notes (Stumpf 1890, pp. 127--219; Butler and Green 2002, p. 264). </Li> <P> "A stable tone combination is a consonance; consonances are points of arrival, rest, and resolution ." </P> <P> An unstable tone combination is a dissonance; its tension demands an onward motion to a stable chord . Thus dissonant chords are "active"; traditionally they have been considered harsh and have expressed pain, grief, and conflict . </P>

A group of notes in music that produce a stable or calm sound could be described as