Mandelbaum became interested in microtonality after listening to a lecture by Paul Hindemith in which Hindemith inadequately debunked various alternative forms of tuning. He began a correspondence with Adriaan Fokker which led to a six-week stay in Haarlem in 1963, during which he composed music using Euler's genera under Fokker's tutelage. The result was "10 Studies in 31-Tone Temperament", which premiered on the Fokker organ in Haarlem.
Mandelbaum's motivation to use the 31 equal temperament arose from its close approximation to just intonation; Mandelbaum preferred the equal temperament to just tuning out of convenience, as it produced one tuning of a keyboard with which it was possible to explore approximations of chords to just tuning in any key. Although well known for exploring alternate tunings, Mandelbaum still uses conventional tuning in about 80% of his music. Mandelbaum attributes his use of conventional tuning to his reluctance to use keyed instruments (such as woodwinds) in tunings other than those that they were designed for.