A Similarity Measure of Musical Notes Based on Psychoacoustics of Loudness and Pitch Perception

Musical note similarities are usually verified by subjective tests and timbre comparisons. However, for one with no background in frequency analysis and without spectral clue in spectral comparison, it might not be easy for one to see how similar two sounds are. This work proposed a simple index for similarity measurement of musical notes, based on psychoacoustics of pitch and loudness perception, called musical note similarity index (MNSI). It was intended to use as a clue for spectral comparison and defined as a subtraction inverse of normalized summation of penalty weights for each harmonic amplitude and frequency exceeding the just noticeable differences (JNDs). Experiments were done and results were statistically analyzed. The correlation and t-test analysis showed that the MNSIs were well correlated with the subjective evaluations of sound similarity. Statistically, the Pearson correlation coefficient of the test was 0.9396 with 99% confidence.