This piece is divided into two clear halves. The first alternates fast upbeat flourishes in rhythmic unison, with freer, unmeasured material, the gestural impetus from these upbeats being released in the subsequent, slower senza misura sections. This pattern, of moving from fast to slower material, which occurs repeatedly in the first part of the piece, is used as an obsessive, archetypal shape throughout Chamber Music on both small and large scales. It occurs only once in the second part of the piece, but lasts through its entire duration, as the ensemble moves from the maximum density of the start of the second half, gradually unwinding towards the calmer, slower ending. The way in which each of these sections is built and organised is outlined below, but before moving to look at this some mention should be made of the main influences upon this gestural conception of the material within Chamber Music. These principally come from electroacoustic music and in particular, spectromorphology , with its concepts of morphological archetype (attack/decay, continuant etc.) and gestural stringing (whereby these units are grouped into larger units). The aim, particularly in the first part of the piece, was to apply these electroacoustically-based ideas to instrumental material, in the shaping of individual sections and building them into a larger structure, rather than through any detailed means of pre-organisation.
The pitch material for the piece reuses the chord matrix created for fffppp but here with very different results. Instead of treating each chord in each register as a separate unit, here the six different columns (each containing six chords) are used together rather as scales or large sets of pitches as follows: