Groups of 2s and 3s may be combined in various ways to build pulse streams of 5 (3+2), 7 (2+2+3), 8 (2+3+3), 9 (2+2+2+3), and even longer groupings. (The numbers in parentheses can be reordered freely.) This produces what is often called “irregular” or “mixed” meter. However, as with the common triple metric structure, the irregularity—mixed 2s and 3s—is concentrated on one level only. Signatures for these meters me be notated by showing the smaller groupings within the measure. For example, a signature of 8/8 may be written:
2+3+3, 3+2+3, 3+3+2, 2+2+2+3, and so on.
8 8 8 8
Ex. 49 shows a metric structure containing a 5-group (quintuple meter) expressed 2+3 in level B. The signature will be 5/8 rather than 10/16, the only other possibility. If we think about how this might be conducted, we will realize that the irregularity exists on one level only. If level C is at the right speed for the beat, we would conduct in five even pulses, possibly by adding another outward gesture after the “3” of the typical 4-beat conducting pattern. Try it, and count along.
If level C is too fast and level B is chosen as the beat, we must conduct in 2, with the second beat lasting an eighth note longer. This can be accomplished by slowing down somewhat after the count 2 ictus. Try it, and count along.
The notation in levels A, C, and D clearly show periodicity. We could say, then, that this metric structure is three-quarters regular, and one quarter irregular! Again, as with triple metric structure, this one irregular level permeates the entire structure, whether it is the beat or not.
What are the possible time signatures for the metric structure in Ex. 50? Regarding conducting this structure, if level B were chosen as the beat, the 3-pattern with a shorter count 2 can be used, the downbeats would fall every 8 counts. If the tempo of the structure were slow enough, and level C were chosen as the beat, a conductor might simply use both the 2- and 3-patterns in the appropriate sequence.
Ex. 50 8/8, in groupings of 3, 2, and 3.
The composer might suggest this treatment by using a succession of time signatures, as shown in Example 51.
Ex. 51 8/8, using time signatures to show the 2- and 3-groupings
This is a good time to revisit the question of whether metric accents should be given added emphasis in performance. It may seem that the 8/8 notation in Ex. 50 suggests a performance that emphasizes the first pulse in each group of 8, counted 1-2-3-4-5-6-7-8, 1-2-3-4-5-6-7-8, 1-2-3-4-5-6-7-8 and conducted in a sudivided 3 pattern. Similarly, the notation in mixed meter might suggest more frequent emphases: 1-2-3, 1-2, 1-2-3; 1-2-3, 1-2, 1-2-3, etc. However, keeping the speed of the eighth note the same for both notations, there is really no reason to assume different accent strategies in performance. Fortunately, we are rarely confronted with a “bare bones” metric structure; melody, harmony, texture, instrumentation, and—most important—tempo will help us to decide.
Try conducting these examples at different tempos, say eighth note = 102, then eighth note = 202. You will find that changing the tempo alone is enough to favor one interpretation over the other.