A match score provides a semantically-meaningful quantification of the aural similarity of two chromae from two corresponding audio sequences. The match score can be applied to the chroma pairs of two corresponding audio sequences, and is independent of the lengths of the sequences, thereby permitting comparisons of matches across subsequences of different length. Accordingly, a single cutoff match score to identify “good” audio subsequence matches can be determined and has both good precision and good recall metrics. A function for determining the match score is determined by establishing a function PM indicating probabilities that chroma correspondence scores indicate semantic correspondences, and a function PR indicating probabilities that chroma correspondence scores indicate random correspondences, repeatedly updating PM and the match function based on existing values of PM and the match function as applied to audio subsequences with known semantic correspondences.