The consonance of chords: The effect of subsemitone changes to each of the notes in a trichord on its perceived consonance

Consonance plays a key role in how listeners experience music, but the factors influencing consonance perception remain a topic of discussion, for instance regarding the role of the familiarity of note combinations. Previous empirical studies of consonance have used common, familiar chords, making it harder to separate the effect of acoustic features from familiarity. Here we explored consonance perception in an unfamiliar, non-standardly tuned 0-5-10 trichord. A test was conducted in which 100 musicians and 100 nonmusicians compared the consonance of an original, non-standard, 0-5-10 chord and an adapted version, in which the lowest, middle or upper note was raised or lowered with 25 or 50 cents. According to a model based on continuous acoustic features, any adaptation to a 0-5-10 chord should yield a comparable decrease in consonance. We indeed found a general consonance decrease, but this was stronger for adaptations enlarging the distance between the lowest and the upper note, i.e. lowering the lowest or raising the highest note, than for other adaptations. These results deviate from the models predictions and from patterns observed in standard, more familiar chords. Future research should examine the generalizability of these findings to other chords than the 0-5-10 trichord.