A MIDI Sequencer That Widens Access to the Compositional Possibilities of Novel Tunings

We present a new Dynamic Tonality MIDI sequencer, Hex, that aims to make sequencing music in and across a large variety of novel tunings as straightforward as sequencing in twelve-tone equal temperament. In order to enable the intuitive visualization and dynamic manipulation of tuning, it replaces the piano roll used in conventional MIDI sequencers with a two-dimensional lattice roll (see Figure 1). It is compatible with the Dynamic Tonality line of software—which currently consists of the microtonal synthesizers TransFormSynth, The Viking, and 2032—and, for static tunings, with any synthesizer that handles channel pitch bend.

In conventional piano roll sequencers, a piano keyboard is displayed on the left side of the window, and white and black note lanes extend horizontally to the right, into which a user can draw a sequence of notes. Similarly, in Hex, a button lattice is displayed in its own pane on the left side of the window, and horizontal lines are drawn from the center of each note to the right. These lines function as generalized note lanes, just like in piano roll sequencers, but with the added benefit that each note lane’s height is always proportional to its pitch, even if the user changes the tuning. The presence of the button lattice on the left side of the window illustrates exactly which buttons a performer would play in order to replicate the sequence when playing a physical button lattice instrument, such as the C-Thru AXiS-49 (www.c-thru-music.com) or the Thummer (www.thummer.com).

Dynamic Tonality is an audio synthesis and control framework that helps musicians explore novel tunings using a small number of intuitive parameters, and provides several new musical opportunities. First, it enables users to morph between many well-known tunings and demonstrates both their structure and their relation to a broad continuum of tunings. For example, a single parameter moves the tuning of tones in a repeating scale through a continuum containing a variety of notable tunings, such as seven-tone equal temperament (7-TET), 19-TET, various meantones, 12-TET, Pythagorean, 17-TET, 22-TET, and 5-TET (Milne, Sethares, and Plamondon 2007). Second, it affords a two-dimensional isomorphic note layout—a representation (see Figure 2) for visualizing, manipulating, and fingering pitch sets in a way that is consistent across key transpositions (Keislar 1987) and many diverse tunings (Milne, Sethares, and Plamondon 2007, 2008). Finally, it can temper the partials of individual tones to match the underlying scale’s tuning, which allows sensory dissonance to be minimized in any tuning, and introduces novel classes of timbre (Sethares 2004; Sethares et al. 2009).

Figure 1.

Hex uses a lattice roll in place of the traditional piano roll. This enables unfamiliar microtonal scales to be intuitively visualized, and their tuning to be dynamically manipulated. In this example, three octaves of a ten-tone microtonal moment of symmetry (MOS) scale are indicated by the light-colored buttons and lanes. The light buttons/lanes can be thought of as generalized “diatonic” tones, the dark buttons/lanes as generalized “chromatic” tones.

Figure 2.

A two-dimensional isomorphic note layout.

We hope that this combination of features will facilitate the exploration of tuning as a creative tool in compositions and performances. For example, Andrew Milne’s Magic Traveller and Hanson demonstrate how Dynamic Tonality can be used to explore scales and tunings radically different from those used in conventional Western music. (Hex project files are available online at www.dynamictonality.com.) William Sethares’ C to Shining C (www.cae.wisc.edu/~sethares/spectoolsCMJ.html) demonstrates how Dynamic Tonality can be used to create progressions of extravagant tuning bends that seem to function similarly to chord progressions in Western tonal harmony. C to Shining C actually gets its name from its use of a progression of C major chords tuned in different ways, rather than a progression of different chords. Dynamic Tonality can also dynamically...