Music : How rhythm is used to create tension and repose in music
Rhythm is everything that has to do with organization of musical elements in time. Rhythm includes pace, tempo, meter and an almost infinite number of ways in which long or short durations of sound and silence make up patterns in time. These manipulations of meter to form patterns are important factors because they are the primary means of providing both tension and repose. There are many pattern devices in which tension can be created, such as meter alterations and ostinato. An examination of which specific actions taken with pace, tempo, and meter create either tension or repose is in order to define how rhythm itself creates these feelings in the listener.
A sense of repose results when some one element supplies unity by remaining unchanged while the other elements are changing dramatically. The stability of this rhythm provides a norm for the listener that suppresses the tension. However, when rhythm is subjected to considerable variation, the unpredictability of the variation and the increased amount of information the listener must process can generate a great deal of tension.
Musical pulse is a series of undifferentiated impulses all of equal length and emphasis. People usually perceive these pulses in groups of two or three, because of stresses or accents (real or imagined) at the start of the first pulse of each group. There are usually pulse groups at more than one level of a piece; sometimes there are different pulses at several levels simultaneously. For instance, Giuseppe Tartini’s Symphony in A Major, third movement, has a great deal of activity in the violins at a pulse rate twice as fast as that of each basic pulse. This results from dividing each basic pulse into two parts.
Pace is the rate of activity for any musical element, perceived in relation to some norm. Once that norm is established, any increase or decrease in the rate at which sounds change is a change in pace. Increasing the pace of any element increases the level of tension. For instance, speeding up the pulse, increasing the volume, and changing the quality of the sound all increase the tension. However, decreasing the rate of any of these creates a sense of repose. For instance, in John Coltrane’s A Love Supreme, the changes in pace coincide with the points of greatest tension. The solo develops while increased activity is added to the constant background of drums, bass and piano. The greatest level of tension is created by playing higher pitches at a faster pace, while the greatest level of repose is created by slowing the pace and playing lower pitches.
Tempo is the relative speed of a piece as marked by the number of pulses within a given time span. The more basic pulses within a given time span, the faster the tempo. A normal heart rate is seventy-two to seventy-six pulses per minute, and as a rule of thumb, tempos close to a normal heart rate can be considered a moderate speed. Tempos on either side can be considered faster or slower. Unconsciously, listeners expect a steady state as a norm in a piece of music. Changes in tempo intrude strongly on our awareness and produce tension or repose. For instance, familiarity with a steady sense of pulse in a particular musical tradition such as classical or jazz, can create expectations. If these expectations are denied, the level of tension is heightened. If the expectations are fulfilled, the level of tension will be considerably lower. There are four kinds of tempo change: an abrupt shift in the basic pulse rate, accelerando, ritardando, and rubato. Accelerando is a gradual increase in the basic pulse rate. Ritardando is a gradual decrease in a basic pulse rate. Both accelerando and ritardando help provide smooth transitions. Rubato is a constant give-and-take in a basic pulse rate. Abrupt tempo shifts such as rubato have dramatic effects, heightening or lowering the tension suddenly and intensifying the impact of a musical idea. Since any change in a basic pulse rate is easily perceived, composers use tempo changes for a variety of effects, such as changing the mood or the beginning or end of a musical idea.
Meter is the marking of musical time by musical pulses, which can operate separately or become building blocks for larger metrical groupings. There are three types of metrical conflict – syncopation, superimposed subdivision, and suppressed meter. They always create conflict or ambiguity, which increases the level of tension in a musical piece. Syncopation is the unexpected absence or displacement of the normal first-pulse accent that defines the basic meter group. It is one of the most common tension-raising devices in music. Many syncopated rhythms placed together can create great excitement for the listener. For example, in Peter Ilich Tchaikovsky’s Swan Lake “Valse”, the normal accent of the fast three-pulse basic meter is contradicted by repeated stress on the second pulse of the group while the basic pulse continues.
