Signatures and Earmarks:
Computer Recognition of
Patterns in Music
By David Cope
http://arts.ucsc.edu/faculty/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
By Mozart
(a)
(b)
Piano Sonata
K.280(1774) mvt. 1,
mm. 107-8
Piano Concerto
K.453(1784), mvt.1,
mm. 162-3
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)
1 -4 -3 -2 -1
1 -3 -4 2
(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.