Chacune des quatre parties peut être jouée séparément.

For one year, between the fall of 1970 and the fall of 1971, I worked on what turned out to be the longest piece I have ever composed. Drumming lasts from 55 to 75 minutes (depending on the number of repeats played) and is divided into four parts that are performed without pause. The first part is for four parts that are performed without pause. The first part is for four pairs of tuned bongo drums, stand-mounted and played with sticks; the second, for three marimbas played by nine players together with two women’s voices; the third, or three glockenspiels played by four players together with whistling and piccolo; and the fourth section is for all these instruments and voices combined.

While first player the drums during the process of composition, I found myself sometimes singing with them, using my voice to imitate the sounds they made. I began to understand that this might also be possible with the marimbas and glockenspiels as well. Thus the basic assumption about the voices in Drumming was that they would not sing words, but would precisely imitate the sound of the instruments. The women’s voices sing patterns resulting from the combination of two or more marimbas playing the identical repeating pattern one of more quarter notes out of phase with each other. By exactly imitating the sound of the instruments, and by gradually fading the patterns in and out, the singers cause them to slowly rise to the surface of the music and then fade back into it, allowing the listener to hear these patterns, along with many others, actually sounding in the instruments. For the marimbas, the female voice was needed, using consonants like "b" and "d" with a more or less "u" (as in "you") vowel sound. In the case of the glockenspiels, the extremely high range of the instrument precluded any use of the voice and necessitated whistling. Even this form of vocal production proved impossible when the instrument was played in its higher ranges, and this created the need for a more sophisticated form of whistle: the piccolo. In the last section of the piece these techniques are combined simultaneously with each imitating its particular instrument.

The sections are joined together by the new instruments doubling the exact pattern of the instruments already playing. At the end of the drum section three drummers play the same pattern two quarter notes out of phase with each other. Three marimba players enter softly with the same pattern also played two quarter notes out of phase. The drummers gradually fade out so that the same rhythm and pitches are maintained with a gradual change of timbre. At the end of the marimba by three glockenspiels in their lowest range so that the process of maintaining rhythm and pitch while gradually changing timbre is repeated. The sections are not set off from each other by changes in key, the traditional means of gaining extended length in Western music. Drumming shows that it is possible to keep going in the same key for quite a while if there are instead considerable rhythmic developments together with occasional, but complete, changes of timbre to supply variety.

I am often asked what influence my visit of Africa in summer of 1970 had on Drumming. The answer is confirmation. It confirmed my intuition that acoustic instruments could be used to produce music that was genuinely richer in sound than that produced with electronic instruments, as well as confirming my natural inclination towards percussion (I became a drummer at the age of 14).

The transition from glockenspiels to the last section of the piece, for all instruments and voices combined, is made by a new musical process I call build-up and reduction. Drumming begins with two drummers building up the basic rhythmic pattern of the entire piece from a single drum beat, played in a cycle of twelve beats with rests on all the other beats. Gradually additional drumbeats are substituted for the rests, one at a time, until the pattern is completed. The reduction process is simply the reverse where rests are gradually substituted for the beats, one at a time, until only a section leads to a build-up for the drums, marimbas, and glockenspiels simultaneously.

There is, then, only one basic rhythmic pattern for all of Drumming. This pattern undergoes changes of phase position, pitch, and timbre, but all the performers play this pattern, or some part of it, throughout the entire piece.

• I : pour 4 paires de bongos accordés, 17 à 25 minutes
  
• II : pour 3 marimbas (9 interprètes , 2 voix de femmes, 18 à 26 minutes
  
• III : pour 3 glockenspiels (4 interprètes), piccolo, 11 à 16 minutes
  
• IV : pour l'ensemble complet, 9 à 19 minutes