ABSTRACT
In the alternating-hands method for generating rhythmic canons composed of “good” rhythms, described in the preceding chapter, the right and le hands continually take turns striking the instrument, analogous to the way our feet do on the ground while we walk, except that, depending on the method employed, the durations between consecutive right-and le -handed strokes may vary. For example, in the rhythm of Figure 28.8, the duration between the rst onset (right-hand) and the second onset (le -hand) is one pulse, but the duration between the third onset (right-hand) and the fourth onset (le - hand) is two pulses. In the method described in this chapter, the rhythm emerges from the process of accenting the proper onsets with each hand while maintaining all the durations between le - and right-handed strokes equal to one pulse. In other words, some strokes may be louder than others, or they may dier in timbre, or tonality. Indeed, the so sounds may even be so muted that they are inaudible, or the hand may stop just before coming into contact with the instrument. e important point is that the motion of the hands consists of a continuous pendular alternation of the right and le hands, such that all durations between adjacent pulses are equal. In other words, the downward motions of the hands trace all the pulses of the rhythm.*
Toggle rhythms are those cyclic rhythms that when played using the alternating-hands method, have their onsets divided into two consecutive sets, such that the onsets of the rst set are played consecutively with one hand, and subsequently the onsets of the second set are played consecutively with the other hand. us, playing this way feels as if one hand responds to a question posed by the other hand, analogous to the customary call-andresponse method of singing existent in much of sub-Saharan Africa. e most pleasing and interesting results with this method are obtained when the le and right hands strike drums that are tuned dierently, so that they produce sounds of distinct tones or timbres. However, even on a single drum, the le and right hands will almost always produce distinct sounds, since they strike the drum skin at dierent locations, and thus the eect will still be audible and operative. However, even if all the accented strokes sound the same,
the system yields good timelines. Indeed, in some musical practices such as sub-Saharan Africa, timelines by their usual denition have the property that they do not contain accents, that is, all their onsets have equal importance.
