List of approaches to musical tuning

Musical tuning can be approached in many different ways. Here are some of the currently-established theories and approaches.

Xen concepts for beginners provides a solid foundation to start from in exploring this assortment of tunings.

Defined approaches

Shape-based

• Equal-step tunings: Tunings that use a single interval (and combinations thereof) to form a subtle monoculture of intervals. These include edos (equal divisions of the octave), but also edonoi (equal divisions of nonoctave intervals).
• Moment of symmetry (MOS): Tunings (or better, scales) that use iterations of a generating interval, modulo a period interval, to produce scales of two step-sizes.
• Tetrachordal scales: the use of divided fourths as building blocks for composition.

Frequency ratio-based

• Just intonation: The tuning of pitches so that their fundamental frequencies are related by ratios of whole numbers. An infinite world of numerous models:
  • Adaptive just intonation
  • Combination product sets
  • Detempering (including ringer scales)
  • Fokker blocks
  • The harmonic series and subharmonic series
  • Harmonic limits and harmonic classes
  • Isoharmonic chords
  • Just intonation subgroups
  • NEJI scales (near-equal just intonation)
  • Overtone scales/AFDOs
  • Primodality
  • Tonality diamonds
  • Tritriadic scales
  • Undertone scales/IFDOs
  • etc.
• Timbral tuning: An approach similar to just intonation, but using an instrument's actual, non-harmonic overtone spectrum (e.g. the partials of a metal bar, drum head, or synthesized timbre) to relate frequencies instead of the harmonic series.
• Regular temperaments (including linear temperaments): a centuries-old practice that has recently undergone a mathematical facelift, in which just intonation is selectively and regularly detuned in various ways, to better meet a variety of compositional desires
• Historical temperaments: The (somewhat forgotten) use of Pythagorean tuning, meantone tunings and well temperaments in Western common practice music.
• Xenharmonic series: Just intonation but the entire matrix of just intervals is stretched, squished or otherwise warped or manipulated for interesting effect.

Musical traditions of indigenous, ancient, and/or non-Western cultures

• African (dozens of distinct traditions)
• Ancient Greek
• Arabic
• Byzantine
  • Orthodox Wiki page
• Croatian (including the Istrian scale)
• Equipentatonic or equiheptatonic scales
• Georgian
• Indian (e.g. North, South)
• Indonesian (most famously gamelan)
• Iranian (Persian)
• Pre-Columbian South American (e.g. Maya, Inca, Aztec)
• Thai
  • Wikipedia page
  • r/GlobalMusicTheory reading list
• Turkish

Further reading: the r/GlobalMusicTheory Wiki.

Subjective processes

The following approaches describe the subjective exploration process or its representations rather than its objective, audible result:

• Contextual Xenharmonics: The exploration of why things sound the way they do to some and not others.
• Empirical: A form of hands-on field research as opposed to a form of acoustical or scale engineering, where tunings are specifically derived from listening and playing experiments carried out in the pitch continuum.
• Pretty Pictures that represent scales in one way or another.
• Musical notation: Pretty pictures for the purpose of writing music down.
  • Nominal-Accidental Chains: The most common approach to notation
• The notion of a Scalesmith who builds scales, with various methods, perhaps for single occasions.
  • Mathematically based scales
  • Acoustically-based scales (resonant frequencies of performance space, for example)
  • Scale transformation and stretching
  • Counter-intuitive, random, or arbitrary scales

See also

• Taxonomies of xen approaches