Signatures and Earmarks: Computer Recognition of Patterns in Music By David Cope Presented by Andy Lee

Overview Two types of patterns for analyzing music Signatures Earmarks Other than just notes, harmony, rhythm …

Signatures Definition A term for motives common to two or motive works of a given composer What is this for? Can tell us what period of music history a work comes from. Can tell the probable composer of that work

Signatures Description Typically 2 to 5 beats in length Often composites of melodic, harmonic, and rhythmic elements Usually occur between 4 and 10 times in any given work Variation often include transposition, diatonic interval alteration, rhythmic refiguring, and registral and voice shifting

Signature - example (a) (b) Piano Sonata K.280(1774) mvt. 1, mm Piano Concerto K.453(1784), mvt.1, mm By Mozart The melody has been truncated with a more active version of the accompaniment. (from 1774 to 1784, 10 years)

Signatures Stylistic Analysis Observing a signature change and develop over time can provide valuable insights into how a given style matures and how one can differentiate by ear the various periods in the life of a composer Tend to articulate the ideas and materials composers have in common, and what make each composer unique.

Signature - placement Five examples of a Viennese signature. Versions of a signature found in Mozart ’ s Piano Sonata K.284, mvt. 2: (a) m.16; (b) m.30; © m.46; (d) m.69; (e) m.92; A Premature tonic bass note under a dominant chord, or a late-sounding dominant over a tonic pedal point. Experienced listeners can tell the misplaced signature

Signature - similarity (a) (b) Using intervals shows more similarity in the two patterns than using pitches. To the ear, these are easily identifiable as simple variations of the same pattern

Signature - EMI EMI (Experiments in Musical Intelligence) A tunable program to let real signature pass 3 basic rules for pattern matching 1.Allowing one step difference 2.Allowing different direction (2  -2) 3.Allowing extra note

Earmarks Definition Patterns in music indicate attributes besides style Identified most easily by ear and tend to mark specific structural location in a work Can tell us what movement of a work we are hearing Can foreshadow particularly important structural events Can contribute to our expectations of when a movement or work should climax or end

Earmarks As Gestural Information Variations of earmarks point out their gestural nature Can typically be described in general terms Trill followed by a scale An upward second followed by a downward third Location: appear at particular points in compositions Finding earmark helps pinpoint important nexus point

Earmark - example An earmark from the first movements of Mozart ’ s Piano Concertos: K.238, mm. 86-7

Earmarks As an aid to Structural Perception Misplaced earmarks can cause a disruption in an educated listener ’ s perception of the apparent musical structure. Earmarks which do not precede anticipated sections, occur out of sequence, or are ill-timed can cause rifts in the antecedent-consequent motion so important to musical structure.