Cage's rapid evolution in 1951-2 -- from the Concerto for prepared piano to 4' 33" in eighteen months -- may have been encouraged not only by zen studies but also by support from fellow artists with whom he was associated. In Tudor he had a dedicated performer (hence so much piano music) and an assistant in the electronic studio. In Robert Rauschenberg, whom he met in 1948,1 he found a painter with similar concerns for the small currency of experience. And in Morton Feldman ( 1926-87), Earle Brown (b. 1926), and Christian Wolff (b. 1934) he discovered younger composers willing to join his pursuit of non-intention: Feldman and Wolff came into his orbit in 1950; Brown joined the group two years later.
Some of Wolff's first pieces use radically limited materials: just three notes within the minimal chromatic range of a major second in his Duo for violins ( 1950). Meanwhile Feldman was taking an almost opposite tack in prescribing pitch as little as possible. His Projections and Intersections are series of 'graph' compositions in which, as in the Music of Changes, time is represented by space, and in which the spaced boxes specify only instrument, register, number of simultaneous sounds,s mode of production, and duration. The two series differ in that the Projections are to be consistently quiet, while in the Intersections'the player is free to choose any dynamic at any entrance but must maintain sameness of volume' -- though 'what is desired in both. . . is a pure (non-vibrating) tone'.2 Example 20 shows the opening of Projection II, where the dashed lines mark off units of a second; the first sound heard is a five-note chord in the extreme bass of the piano, followed by a middlerange trumpet note, a note in the mid-treble of the piano, and so on. In other works of the same period, such as the Extensions series or Structures for string quartet, Feldman used conventional notation in order to achieve non-compulsion differently, by having delicate figures repeated over and over again. But the ideal is essentially the same: as Cage pointed out, ' Feldman's conventionally notated music is himself playing his graph music'.3 The exceptions to his world of low-density, lowspeed, low-volume music were few and extreme: the hectically eventful Intersection III for piano, or the unrealized and probably unrealizable Intersection for tape.4____________________