• Composer Aldo Clementi, 1925
• Composer Benjamin Burwell Johnston, Jr., 1926

Aldo Clementi was born in Catania, Italy. He studied the piano, graduating in 1946. His studies in composition began in 1941, and his teachers included Alfredo Sangiorgi and Goffredo Petrassi. After receiving his diploma in 1954, he attended the Darmstadt summer courses from 1955 to 1962. Important influences during this period included meeting Bruno Maderna in 1956, and working at the electronic music studio of the Italian radio broadcaster RAI in Milan.

Poesia de Rilke (1946) was the first work of his to be performed (Vienna, 1947). Of more significance was the premiere of Cantata (1954), which was broadcast by North German Radio (Hamburg) in 1956. In 1959 he won second prize in the ISCM competition with Episodi (1958), and in 1963 he took first prize in the same competition, with Sette scene da "Collage" (1961).

He taught music theory at the University of Bologna from 1971 to 1992.

Clementi died on 3 March 2011.

In 1983 David Fanning described Clementi's style of decelerating canons as "sharing in the widespread post - serial depression of the 1970s", while in 1988 Paul Griffiths referred to the "Alexandrian simplicity of his solution to the current confusion in music. Clementi himself described his works as "an extremely dense counterpoint, relegating the parts to the shameful role of inaudible, cadaverous micro - organisms".

His music has been featured at Ultima, the Oslo Contemporary Music Festival (2009), performed and recorded by ensembles including the Quatuor Bozzini, the Ives Ensemble and the Contemporary Music Ensemble of Wales and broadcast by BBC Radio 3.

Ben Johnston was best known for extending Harry Partch's experiments in just intonation tuning to traditional instruments through his system of notation. Johnston's compositional style is eclectic, employing serial processes, folksong idioms (String Quartets 4, 5 and 10), repetitive processes, traditional forms like fugue and variations, and intuitive processes. However, his main goal, "has been to reestablish just intonation as a viable part of our musical tradition" and "ultimately, what Johnston has done, more than any other composer with roots in the great American musical experiments of the '50's and '60's [sic], is to translate those radical approaches to the nature of music into a music that is immediately apprehensible".

Most of his later works used an extremely large number of pitches, generated through just intonation procedures. In them, Johnston forms melodies based on an "otonal" eight - note just - intonation scale made from the 8th through 15th partials of the harmonic series) or its "utonal" inversion. He then gains new pitches by using common - tone transpositions or inversions. Many of his works also feature an expansive use of just intonation, using high prime limits. His String Quartet No. 9 uses intervals of the harmonic series as high as the 31st partial. Thus Johnston uses, "potentially hundreds of pitches per octave," in way that is, "radical without being avant - garde," and not for the creation of, "as-yet-unheard dissonances," but in order to, "return... to a kind of musical beauty," he perceives as diminished in Western music since the adoption of equal - temperament. "By the beginning of the 1980s he could say of his elaborately microtonal String Quartet no.5..., "I have no idea as to how many different pitches it used per octave".

Johnston's early efforts in just composition drew heavily on the accomplishments of post - Webern serialism. His String Quartet No. 4 "Amazing Grace", however, ushered in a change of style in which tonality plays a central role. It was commissioned by the Fine Arts Music Foundation of Chicago, and was first recorded by The Fine Arts String Quartet on Nonesuch in 1980 (and reissued on Gasparo as GS205). The String Quartet No. 4, perhaps Johnston's best known composition has also been recorded by the Kronos Quartet, and the Kepler Quartet recorded it on a CD for the New World Records label, the first of a proposed series to document Johnston's entire cycle of string quartets. It is on this CD that String Quartet No. 3 was recorded (for the first time) to create a pairing, with String Quartet No. 4, called Crossings. The Third Quartet was premièred this way by the Concord String Quartet at New York's Alice Tully Hall, on March 15, 1976 (the composer's fiftieth birthday).

Beginning in the 1960s, Johnston had proposed an approach to notating music in just intonation, redefining the understanding of conventional symbols (the seven "white" notes, the sharps and flats) and adding further accidentals, each designed to extend the notation into higher prime limits. Johnston‘s method is based on a diatonic C Major scale tuned in JI, in which the interval between D (9/8 above C) and A (5/3 above C) is one Syntonic comma less than a Pythagorean perfect fifth 3:2. To write a perfect fifth, Johnston introduces a pair of symbols representing this comma, + and –. Thus, a series of perfect fifths beginning with F would proceed C G D A+ E+ B+. The three conventional white notes A E B are tuned as Ptolemaic major thirds (5:4, Ptolemy's intense diatonic scale) above F C G respectively. Johnston introduces new symbols for the septimal ( & ), undecimal (↑ & ↓), tridecimal ( & ), and further prime extensions to create an accidental - based exact JI notation for what he has named "Extended Just Intonation".

Though, "this notation is not tied to any particular diapason," and, "what remains constant are the ratio relations between pitches," "most of his works utilize A = 440 as the tuning note," making C 264 Hertz. Thus a string quartet is tuned C-, G-, D-, A, E.

Johnston taught composition and theory at the University of Illinois at Urbana - Champaign from 1951 to 1986 before retiring to North Carolina. While there he was in contact with such "avant - garde" figures as John Cage, La Monte Young, and Iannis Xenakis. Johnston's students include Stuart Saunders Smith, Neely Bruce, Thomas Albert, Michael Pisaro, Manfred Stahnke, and Kyle Gann. He also considered his practice of just intonation to have influenced Manfred Stahnke, and with James Tenney, Larry Polansky.

Johnston began as a traditional composer of art music before working with Harry Partch, helping the senior musician to build instruments and use them in the performance and recording of new compositions. After working with Partch, Johnston studied with Darius Milhaud at Mills College. It was in fact Partch himself who arranged for Johnston to study with Milhaud. In 1952 Johnston met John Cage, who invited him to come to New York in the summer to study with him. Though Johnston decided he did not have sufficient time to prepare for such studies, he did go to New York for several weeks, where he assisted, along with Earle Brown, in the production of Cage's eight - track tape composition, Williams Mix. He did study with Cage later, in 1957 and 1959. Cage encouraged him to follow his desires and use traditional instruments rather than electronics or newly built ones. Unskilled in carpentry and finding electronics then unreliable, Johnston struggled with how to integrate microtonality and conventional instrumentals for ten years and struggled with how to integrate microtones into his compositional language through a slow process of many stages. However, since 1960 Johnston used, almost exclusively, a system of microtonal notation based on the rational intervals of just intonation, what Gann describes as a "lifelong allegiance" to "microtonality". Johnston also studied with Burrill Phillips and Robert Palmer.

Other works include the orchestral work Quintet for Groups (commissioned by the St. Louis Symphony Orchestra, Sonnets of Desolation (commissioned by the Swingle Singers), the opera Carmilla, the Sonata for Microtonal Piano (1964) and the Suite for Microtonal Piano (1977). Johnston completed many string quartets.

"Tempered tuning is not the acoustically simplest kind. In just tuning, any interval is tuned so as to eliminate 'beating' (the result of vibrations interfering with each other). Just intonation is the easiest to achieve by ear. In this kind of tuning, all intervals have vibration rates related by small whole-number ratios. The larger the integers of the ratio, the greater the dissonance" (Johnston 2006, 42).

Johnston received many honors, including a Guggenheim Fellowship in 1959, a grant from the National Council on the Arts and the Humanities in 1966, two commissions from the Smithsonian Institution and the Deems Taylor Award. In 2007, the American Academy of Arts and Letters honored Johnston for his lifetime of work. His Quintet for Groups won the SWR Sinfonieorchester prize at the 2008 Donaueschinger Musiktage.

An interview with Ben Johnston can be found in Duckworth 1995. Heidi von Gunden has published a monograph on the composer (von Gunden 1986), and Bob Gilmore has edited the composer's complete writings (Johnston 2006).