Generalized Tonnetze and Zeitnetze, and the topology of music concepts

The music-theoretic idea of a Tonnetz can be generalized at different levels: as a network of chords relating by maximal intersection, a simplicial complex in which vertices represent notes and simplices represent chords, and as a triangulation of a manifold or other geometrical space. The geometrical construct is of particular interest, in that allows us to represent inherently topological aspects to important musical concepts. Two kinds of music-theoretical geometry have been proposed that can house Tonnetze: geometrical duals of voice-leading spaces and Fourier phase spaces. Fourier phase spaces are particularly appropriate for Tonnetze in that their objects are pitch-class distributions (real-valued weightings of the 12 pitch classes) and proximity in these space relates to shared pitch-class content. They admit of a particularly general method of constructing a geometrical Tonnetz that allows for interval and chord duplications in a toroidal geometry. This article examines how these duplications can relate to important musical concepts such as key or pitch height, and details a method of removing such redundancies and the resulting changes to the homology of the space. The method also transfers to the rhythmic domain, defining Zeitnetze for cyclic rhythms. A number of possible Tonnetze are illustrated: on triads, seventh chords, ninth chords, scalar tetrachords, scales, etc., as well as Zeitnetze on common cyclic rhythms or timelines. Their different topologies – whether orientable, bounded, manifold, etc. – reveal some of the topological character of musical concepts.Accepted manuscrip

Ganymed's heavenly descent

Schubert's song “Ganymed” has attracted a great deal of interest from analysts due to its progressive tonal plan, often seen as a challenge to Schenkerian theories of tonal structure, and evocative text. This article draws upon a spatial theory of tonal meaning which helps both to resolve the epistemological impasse faced by reductive theories of tonal structure, and to better access Schubert’s interpretation of Goethe’s text through spatial metaphors that derive from the harmony of the song. It also highlights an allusion to Beethoven's Op. 53 “Waldstein” Piano Sonata in the song that has previously gone unremarked, and identifies this as part of a network of references to Beethoven’s sonata that act both as homage to and critique of Beethoven's middle-period style. These serve both as a window into the song, and into Schubert’s aesthetic stance vis-à-vis his most pre-eminent musical forebear. The theory of tonal space draws upon previous publications, but is re-explained in music-theoretical terms relating to diatonicity and triadicity here. It realizes latent directional metaphors in the diatonic sharp-flat and triadic dominant-subdominant dimensions, which are of hermeneutic value for tonal music. Such a theory helps us interpret Schubert’s tonal plan, explain his choices of keys, and better understand his reading of Goethe's text and aesthetic priorities in setting it to music.Accepted manuscrip

A space for inflections: following up on JMM's special issue on mathematical theories of voice leading

Journal of Mathematics and Music's recent special issue 7(2) reveals substantial common ground between mathematical theories of harmony advanced by Tymoczko, Hook, Plotkin, and Douthett. This paper develops a theory of scalar inflection as a kind of voice-leading distance using quantization in voice-leading geometries, which combines the best features of different approaches represented in the special issue: it is grounded in the concrete sense of voice-leading distance promoted by Tymoczko, invokes scalar contexts in a similar way as filtered point-symmetry, and abstracts the circle of fifths like Hook's signature transformations. The paper expands upon Tymoczko's ‘generalized signature transform’ showing the deep significance of generalized circles of fifths to voice-leading properties of all collections. Analysis of Schubert's Notturno for Piano Trio and ‘Nacht und Träume’ demonstrate the musical significance of inflection as a kind of voice leading, and the value of a robust geometrical understanding of it.Accepted manuscrip

Fourier phase and pitch-class sum

Music theorists have proposed two very different geometric models of musical objects, one based on voice leading and the other based on the Fourier transform. On the surface these models are completely different, but they converge in special cases, including many geometries that are of particular analytical interest.Accepted manuscrip

Verifying the frequency ratios in the musical scale of just intonation with "hear-and-see" learning tools

In engineering colleges, Acoustics often includes the musical scale topic, which is not very popular with most engineering students. In order to face this situation, this paper presents two alternative or complementary “hear-and-see” learning tools for the musical scale of just intonation. The first one combines the hearing of musical notes from an electric organ with the display on an oscilloscope from which the frequency ratios are inferred. Alternatively, the frequencies are computed in advance on the basis of the theoretical frequency ratios, and an audio editor allows to hear the resulting notes, while the PC screen can display similar graphs to those on the oscilloscope.Postprint (author's final draft

Musical Actions of Dihedral Groups

The sequence of pitches which form a musical melody can be transposed or inverted. Since the 1970s, music theorists have modeled musical transposition and inversion in terms of an action of the dihedral group of order 24. More recently music theorists have found an intriguing second way that the dihedral group of order 24 acts on the set of major and minor chords. We illustrate both geometrically and algebraically how these two actions are {\it dual}. Both actions and their duality have been used to analyze works of music as diverse as Hindemith and the Beatles.Comment: 27 pages, 11 figures. To appear in the American Mathematical Monthly

Voicing Transformations and a Linear Representation of Uniform Triadic Transformations (Preprint name)

Motivated by analytical methods in mathematical music theory, we determine the structure of the subgroup $\mathcal{J}$ of $GL(3,\mathbb{Z}_{12})$ generated by the three voicing reflections. We determine the centralizer of $\mathcal{J}$ in both $GL(3,\mathbb{Z}_{12})$ and the monoid ${Aff}(3,\mathbb{Z}_{12})$ of affine transformations, and recover a Lewinian duality for trichords containing a generator of $\mathbb{Z}_{12}$. We present a variety of musical examples, including Wagner's hexatonic Grail motive and the diatonic falling fifths as cyclic orbits, an elaboration of our earlier work with Satyendra on Schoenberg, String Quartet in $D$ minor, op. 7, and an affine musical map of Joseph Schillinger. Finally, we observe, perhaps unexpectedly, that the retrograde inversion enchaining operation RICH (for arbitrary 3-tuples) belongs to the setwise stabilizer $\mathcal{H}$ in $\Sigma_3 \ltimes \mathcal{J}$ of root position triads. This allows a more economical description of a passage in Webern, Concerto for Nine Instruments, op. 24 in terms of a morphism of group actions. Some of the proofs are located in the Supplementary Material file, so that this main article can focus on the applications