Sequence based melody comparison: Tonal-diatonic distinguishing on perceptional pitch hierarchy

The measurement called Edit-Distance for the sequence-based melody comparison in Music Information Retrieval may give inaccurate results in exchange procedure, in comparisons of conjunct interval melodies due to the weighted values depending on hierarchy of disjunct intervals on perception, suggested by Mongeau&Sankoff, for the hierarchy of conjunct interval melodies differs on perception. That is, the melody, the most similar to the query by user may come at the bottom in the ranking of results. This study proposes a solution to the problem with a cognitive research applying probe-tone method. A melody is used in the experiment as a stimulus and a table showing numeric values of perceptional pitch hierarchy to be rated by participants. Statistical results show that perceptional hierarchy of pitches changes according to the character of the melody, i.e. whether it has more disjunct intervals than conjunct intervals, or, vice versa. This phenomenon leads to the attempt to redefine the concepts of tonality and diatonic, for disjunctive interval melodies are more associated with tonality, emphasizing the significant pitches of tonality, while conjunct interval melodies are with diatonic, relating to the other pitches of diatonic scale as well, in the hierarchy. Although melodies with disjunct interval of pitches coincide directly with weighted values of Mongeau&Sankoff, melodies with conjunct interval of pitches consist of a new weighted values and table because of diatonic evaluation on perception. If the new weighted values created in this study are used in the Edit-Distance measurement for sequenced-based melody comparison, melodies retrieved to user would have a more credible ranking.