“Choral intonation practices: an
investigation and a model"
                   Johanna Devaney
          1.   Issues
          2.   Assumptions
          3.   Methodological Overview
          4.   Applications
          5.   Conclusions
          6.   References
9/08/06                  Johanna Devaney - ISSSM 2006   1
                          johanna@music.columbia.edu
1. Issues
    An a cappella’s choir’s tuning cannot be
     consistently related to a single global
     reference point
    Local reference points are formed through a
     combination of horizontal and vertical
     musical factors
    The weighting of the local reference points
     may differ both from piece to piece and
     within a single piece
9/08/06             Johanna Devaney - ISSSM 2006   2
                     johanna@music.columbia.edu
1. Issues
    Consider a piece in C major that modulates to its
     dominant, G major
    How does B, the seventh of the home key, function
     differently at various points in this piece?
         B is the leading tone in C major (I) and the mediant in G
          major (V)
           In C Major (I) B is an unstable pitch, outside of the tonic
             triad, that generally resolves up by step to the tonic (C)
           In G major (V) B is a stable pitch within the key’s tonic triad
9/08/06                        Johanna Devaney - ISSSM 2006                   3
                                johanna@music.columbia.edu
2. Assumptions
    The western tonal system is used as the primary
     reference point for the harmonic/contrapuntal
     activity in the chosen music
         i.e. late pre-tonal early tonal western art music
    Vertical tendencies are addressed in relation to the
     harmonic series and theories of sensory
     consonance (Helmholtz, Terhardt)
    Horizontal tendencies are considered in terms of
     recent theories of tonal tension and attraction
     (Lerdahl, Larson)
9/08/06                       Johanna Devaney - ISSSM 2006    4
                               johanna@music.columbia.edu
2. Assumptions
    Intonation practices are assumed to be
     intentional
         The recordings selected to train the model are
          considered to be “expert” renditions
    The perceived F0 is assumed to be the
     mean frequency over the duration of the
     note or one beat in the current metrical
     context, whichever is shorter
9/08/06                   Johanna Devaney - ISSSM 2006     5
                           johanna@music.columbia.edu
3. Methodological Overview
    Model of intonation
         computational approach
             based on frequency analyses of a number of choral
              recordings
             uses statistical machine learning techniques to
              build a model of choral intonation practices from
              the microtonal pitch variations in the recordings
             provides the model with an objective basis
9/08/06                     Johanna Devaney - ISSSM 2006          6
                             johanna@music.columbia.edu
3. Methodological Overview
    Model of intonation
         theoretical approach
             draws on the various branches of music theory that
              address harmonic and voice-leading practices,
              music forces and expectation, acoustics and
              psychoacoustics, and tuning, temperament, and
              intonation
             provides a contextual depth that empirical analysis
              cannot produce
9/08/06                      Johanna Devaney - ISSSM 2006           7
                              johanna@music.columbia.edu
3. Methodological Overview
                                                                         Received
          Recording                        Score
                                                                        Music Theory
                      Data Collection
                      Data Correlation
                      Computational                       Theoretical
                        Approach                           Approach
                              Generalized Model
9/08/06                            Johanna Devaney - ISSSM 2006                        8
                                    johanna@music.columbia.edu
3. Methodological Overview
    Theories of sensory consonance make a
     case for purely tuned vertical intervals on
     psychoacoustic grounds, as there is a
     greater coincidence of partials between them
     than with tempered intervals.
    Helmholtz on consonance and dissonance
     (1863)
    Terhardt on sensory consonance and tonal
     significance/virtual pitch theory (1974, 1984)
9/08/06              Johanna Devaney - ISSSM 2006     9
                      johanna@music.columbia.edu
3. Methodological Overview
    The horizontal aspects are a little more
     complicated as there is no acoustical
     template to refer to.
    Theories of tonal tension offer tools with
     which to address the horizontal dimension.
    Lerdahl’s tonal pitch space theory (2001)
     formalizes the tendency of a dissonant pitch
     to resolve to a consonant neighbor
         Attraction equation: s2/s1*1/n2
9/08/06                   Johanna Devaney - ISSSM 2006   10
                           johanna@music.columbia.edu
3. Methodological Overview
    Larson (2004, 2005) correlates the forces of gravity,
     magnetism, and inertia explicitly into a single equation
         F = wGG + wMM + wII
             G has a value of 1 or 0
             M = 1/dto2 - 1/dfrom2
             I has a value of -1, 0, or 1
    The tension models provide a means of exploring
     intonational tendencies in linear pitch sequences by
     providing representations of how the pitches within a
     tonal system exist in relation to one another outside of
     the harmonic context in which they occur
9/08/06                           Johanna Devaney - ISSSM 2006   11
                                   johanna@music.columbia.edu
3. Methodological Overview
                                                                         Received
          Recording                        Score
                                                                        Music Theory
                      Data Collection
                      Data Correlation
                      Computational                       Theoretical
                        Approach                           Approach
                              Generalized Model
9/08/06                            Johanna Devaney - ISSSM 2006                        12
                                    johanna@music.columbia.edu
4. Applications
    This methodology allows for a detailed model to be
     built from analyses of numerous recordings of real-
     world performances
    The resultant model may be useful in a number of
     domains
         informing composers about the intonation practices of
          choirs
         voice pedagogy for choral singing
         creating intonationally accurate digital re-creations
         music cognition - particularly in the study of expressivity
9/08/06                       Johanna Devaney - ISSSM 2006              13
                               johanna@music.columbia.edu
5. Conclusions
    The intersection of computational and
     theoretical approaches offers a means of
     addressing the potential conflicts between
     horizontal and vertical intonation tendencies
    The resultant model may serve a normalized
     reference to intonation practices, which is
     potentially useful in a number of domains
9/08/06              Johanna Devaney - ISSSM 2006    14
                      johanna@music.columbia.edu
6. References
    Helmholtz, H. (1863). On the Sensation of Tone. Translated by A.J.
     Ellis. (1954). New York, NY: Dover Publications.
    Lerdahl, F. (2001). Tonal Pitch Space. Oxford: Oxford University
     Press.
    Larson, S. (2004). Musical Forces and Melodic Expectations:
     Comparing Computer Models with Experimental Results. Music
     Perception, 21:4, 457-498.
    Larson, S. and VanHandel, L. (2005). Measuring Musical Forces.
     Music Perception, 21:4, 457-498.
    Terhardt, E. (1974). Pitch, Consonance and Harmony. Journal of
     the Acoustical Society of America, 55, 1061-69.
    Terhardt, E. (1984). The concept of Musical Consonance: A Link
     between Music and Psychoacoustics. Music Perception, 1:3, 276-
     295.
9/08/06                     Johanna Devaney - ISSSM 2006              15
                             johanna@music.columbia.edu