NEW YORK — Ben Johnston, a prolific and influential composer who used microtonal tuning systems to create a large and varied catalog of chamber works, stage pieces, and music for orchestra, choir, voice, and solo piano, died July 21 in Deerfield, Wisc., near Madison. He was 93.
Michael Mitchell, his son-in-law and personal assistant, said the cause was complications of Parkinson’s disease.
Mr. Johnston was an unusual avant-gardist: His music was so melodically engaging, rhythmically vital, and structurally transparent that listeners who were unaware of his tuning experiments and their complex theoretical underpinnings heard his works as essentially neo-Romantic.
In addition to using microtonality — a system in which the octave is often divided into dozens of pitches rather than the traditional 12 — Mr. Johnston sometimes used serial techniques, in which pitches were presented in a predetermined sequence. He invented his own notation systems to account for his tunings, which could change from piece to piece.
His 10 string quartets, for example, are dramatic, sometimes incendiary scores with hard-driving and often tense fast movements as well as ruminative slow movements — with occasional quotations from folk melodies.
Mr. Johnston created several stage works, including “Gambit” (1959), a ballet with a vivid, jazz-tinged chamber score that Merce Cunningham choreographed, and incidental music for a production of Shakespeare’s “The Taming of the Shrew” (1961).
His “Carmilla” (1970), an hourlong chamber opera about a female vampire with a libretto by Wilford Leach, proved a popular draw when it was staged at La MaMa, the experimental theater in Lower Manhattan, shortly after it was completed. So did his final stage piece, “Calamity Jane to Her Daughter” (1989). Based on the possibly fictional letters of its title character, the work is built around themes in a folkish cowboy style.
Unlike Harry Partch, with whom he studied briefly and whose microtonal tuning philosophy he expanded upon, Mr. Johnston did not build specialized instruments for his music. He preferred either to retune conventional instruments or to have players find his pitches between those they were used to playing.
His passion for microtonal music grew out of a desire for intervals that were purer — more fully in tune — than those yielded by equal temperament, a system adopted by composers in the 17th century that made it possible to produce a more or less in-tune sound in any key. In the system it replaced, known as just temperament, individual notes were tuned slightly differently in each key.
“Ben’s incredible mathematical imagination vastly expanded the range of usable harmony, diffracting music into new colors we didn’t know were there,” composer and critic Kyle Gann, a former student of Mr. Johnston’s, said in an e-mail.