Vertical dissonance as an alternative harmonic-related perceptual feature

The purpose of this study is to explore how well dissonance fits as an alternative for a harmonic-related perceptual feature that is easily rated by human listeners. Dissonance is a well-known concept, often described as a sensation of roughness, tension and unpleasantness. For example, dissonant intervals comprised of complex tones have partials that don’t align and therefore give rise to beating. These intervals are also characterised by having complex ratios and have been avoided in classical music for a long time. Furthermore, dissonance may be regarded as the vertical dimension of harmony, with melody and chord progression being the horizontal. In an experiment, 32 listeners rated the dissonance of 92 isolated twoand three-note chords (dyads and triads). Preliminary results show that dissonance was easy for the listeners to rate, which possibly makes it suitable to use as a perceptual feature in future experiments. Furthermore, it was shown that triads, with some limitations, may be regarded as a combination of dyads. Introduction In the field of music information retrieval, a lot of ambition has been put into finding suitable and general terms to describe music from the perceptual perspective. In Friberg et al. (2014) nine perceptual features are proposed on the basis of an ecological approach. That is, the idea that we listen to properties of the sound source rather than just properties of the timbre. This is motivated by the idea that this is closer to how humans perceive sound and thus provides a good basis for the rating of features in music. The perceptual features proposed were dynamics, modality (minormajorness), rhythmic complexity, speed, rhythmic clarity, brightness (timbre), pitch, articulation and harmonic complexity. These were estimated using audio features and compared to human ratings. Harmonic complexity was used as a perceptual feature, which encompasses both the vertical and horizontal dimensions of harmony. Vertical harmony is the perception of simultaneous notes whereas horizontal harmony is the harmonic sequence of notes (chord progression and melodies). In the study by Friberg et al. (2014), harmonic complexity was presumed to be difficult to rate, because it refers to a complex music theoretical analysis involving chord changes and key