Isomorphic keyboard

Practical isomorphic keyboards were developed by Bosanquet (1875), Janko (1882), Wicki (1896), Fokker (1951), Erv Wilson (1975–present), William Wesley (2001),[1] and Antonio Fernández (2009).

[2] Accordions have been built since the 19th century using various isomorphic keyboards, typically with dimensions of semitones and tones.

Two primary benefits are claimed by the inventors and enthusiasts of isomorphic keyboards: A third potential benefit of isomorphic keyboards, dynamic tonality, has recently been demonstrated, but its utility is not proven.

Using a continuous controller, a performer can vary the tuning of all notes in real time, while retaining invariant fingering on an isomorphic keyboard.

Dynamic tonality has the potential to enable new real-time tonal effects such as polyphonic tuning bends, new chord progressions, and temperament modulations, but the musical utility of these new effects has not been demonstrated.