Single Tones Improvisation

Single Tones: Ensemble
On a slow {h} pulse ({h} = 40 or slower) players sound single tones together, one tone to each pulse. There is no thought of key or mode, of tonality or atonality. Each player chooses the next tone in response to the previous two-tone sound. (“Choose” is a tricky word here, for while the players obviously exercise choice in some way, it has more to do with responding than willing.) The players do not select tones in advance, nor does either player follow a melodic line of their own intention. Partners watch each other; this protects them from the temptation to make visual choices on their instruments. 

It is important that the pulse remain slow enough for the players to act on each sound…Since the players cannot predict the future with any certainty, they must stake each step into it on a sensitive, alert, and trusting response to the present sound. This is an adventure in intuition.

Although this exercise was designed for two players at a piano, it works equally well with two players of any like instruments, such as two singers, flutists, or violinists, and might also work well between two different instruments.

Anne Farber, in Improvisation in the Private Piano Lesson