Image: Museumsinsulaner, Public domain — via Wikimedia Commons
Orthotonophonium
| Category | Wind (free-reed keyboard / microtonal harmonium) |
|---|---|
| Country of origin | Germany (late 19th century) |
| Classification | free reed aerophone |
| Wikipedia | en.wikipedia.org |
| Wikidata | Q18026564 |
Overview
The orthotonophonium is a free-reed keyboard instrument designed by the Baltic German physicist and music theorist Arthur Joachim von Oettingen in the late 19th century. Built as a specialised microtonal harmonium, it allows the performer to produce more than the twelve equally tempered notes per octave found on a standard keyboard, making it a research instrument for the study of just intonation and historical tunings.
Origin & History
Oettingen’s interest in tuning theory grew out of the broader 19th-century revival of interest in just intonation following the work of Hermann von Helmholtz. Standard keyboards’ twelve-tone equal temperament approximates the pure intervals of just intonation but cannot reproduce them exactly. To make those pure intervals available in real time, Oettingen designed the orthotonophonium with 53 notes per octave — a division that very closely approximates a chain of pure perfect fifths and pure major thirds. The instrument was built by the Schiedmayer firm in Stuttgart, with surviving examples now held in museum collections including the Musikinstrumenten-Museum in Berlin.
How It’s Played
The orthotonophonium uses a redesigned keyboard layout that groups its many keys into a manageable physical arrangement — broadly similar in principle to a generalised microtonal keyboard, with multiple shorter rows giving access to the 53 distinct pitches per octave. Like a harmonium, sound is produced by air driven across free reeds by a foot-operated bellows system. Performers learn to find the specific keys that correspond to pure intervals in any chord or scale.
Cultural Significance
The orthotonophonium is a rare and historically significant instrument in the lineage of microtonal keyboards. It anticipated the later 20th-century interest in just intonation pursued by composers such as Harry Partch and Ben Johnston, and it remains an object of study in historical and contemporary tuning research.
Related Instruments
- Harmonium – the parent free-reed keyboard family
- – the broader category of free-reed keyboards
- – American sibling tradition
- – another microtonal keyboard concept
- – contemporaneous regional adaptation
Frequently Asked Questions
How many notes per octave does it have?
53 — closely approximating pure perfect fifths and major thirds of just intonation.
Is it still played?
Surviving examples are museum instruments and are demonstrated occasionally in tuning-research contexts.
Image: MIM Orthotonophonium Schiedmayer, photo by Museumsinsulaner, public domain (Wikimedia Commons).