pattern structure and process in piano phase

8/14/2019 Pattern Structure and Process in Piano Phase

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Pattern Structure and Processin Steve Reich's Piano PhasePAUL EPSTEIN

IN his 1968 manifesto, "Music as a Gradual Process," Steve Reich arguesthat once a composer constructs a pattern and sets it in motion by meansof a rigorously defined process further intervention is unnecessary.Even when all the cards are on the table and everyone hears what is gradually happeningin a musical process, there are still enough m ysteries to satisfy all. These mysteries arethe impersonal, unintended, psycho-acoustic by-products of the intended process. 1This statement represents a radical approach to musical form. Reich'sbelief that music can be impersonal, unedited process, rather than an ex-pressive, handcrafted me taphor for process, is a new idea as is the ideathat the role of the composer is not as inventor of personal codes for usto decipher but as a discoverer of impersonal natural phenomena. In ex-periencing process music, the listener's task is also one of discoveryofthe physical laws embodied in the process and of the psychological lawsaffecting the listener's interaction w ith the process. It is in this interactionthat the coming together of impersonal and personal takes place that formsthe key experience of processmusic.Few pieces by Reich or other composers actually present single uneditedprocesses. At the very least, the open-endedness of many processes demandsexternal intervention to terminate them. One of the most successful ofthe relatively pure process pieces, Reich's Piano Phase, composed in 1967,

The preparation o f tfaii e m y was supported by a grant from Temp le University. It was firstpresented as part of a panel, "Minimalism: Cultural and Historical Perspectives," at the Annual Con-ference o f the Am erican Society of University Composers, Colu mb ia, Ohio , April 5, 198 4. At thattime it w as illustrated by examp les generated on a Com modo re 64 personal computer from a programwritten by Maurice Wright. The computer realization of Piano Phase was also used, together withtapes of live performances, in preparing the paper. This was done in order to ensure that discon-tinuities perceived in the phasing process were not the result of performance Inaccuracy. In facteverything d escribed in the paper was verified in b oth live and digital versions.

1 Writings About Music (New York, 1974) , p . 10.

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Reich's Piano Phase 49 5provides us with an excellent example of the surprises that can occur withina continuous process." The piece, written for two pianos but performablealso by marimbas, is in three sections, with melodic patterns of 12, 8, and4 sixteenth-note beats respectively. I will discuss only the firs t-an d lon ge st-section, looking at the inherent structural characteristics of the pattern,together with the phasing process by which the pattern is rotated againstitself, as the source of the musical events of the piece.

Ex.1.

The pattern (see Ex. 1) is actually a nesting of two repeating figures,one of three notes, the other of two. In addition to generating the melodicpattern, these figures function harmonically as the two contrasting so-norities of the piece. Piano Phase begins with the first player repeatingthe pattern, and that is all that player will do through the entire section.The second player enters in unison and after a while very slightly increasesthe tempo. Gradually the two separate until the distance between themis a full sixteenth note. Then the second player briefly matches tempowith the first before resuming the phasing process. The latter procedurecontinues through a full cycle of twelve phases, finally returning to closethe section in unison.The second half of the cycle is a retrograde of the first, with the relation-ship between the two players reversed. (Note that in spite of differentstarting points, phases 1 and 11, 2 and 10, etc., are identical.) Two phasesstand as formal markers: the unison that opens and closes the process, andphase 6, which appears only once, at the mid-point, and precedes the begin-ning of the retrograde. The unison situation is inherently basic, and itsreturn constitutes a conclusion natural enough to the process to justifythe claim of non-intervention.With the process defined as above, we have in effect a series of canons,at distances of from 0 to 11 sixteenth notes, alternating with transitionsin which the two voices are out of phase with each other. Before examiningthe dynamics of the process, let me make several observations about thein-phase situationsphases 0 to 11 as shown in Examp le 2.First, the phases alternate between those in which the two sonorities,E-B-D and Ff-Cf remain intactthat is, each dyad is homogeneousand


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496 The Musical QuarterlyEx.2.

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. .L " L " rrthose in which each dyad includes a note from either sonority. The even-numbered (homogeneous) phases are almost entirely consonant. Withthe exception of phase 6, they consist mostly of perfect consonances,with one pair each of minor thirds and minor sevenths. Phase 6 consistsentirely of perfect consonances. The odd-numbered (heterogeneous) phasesare significantly more dissonant, including three pairs of seconds, twoof sixths, and one of perfect fourths.Looking at the consonant phases, it is predictable that at 0, 4, and 8the F | 's and C f s will be in unison; at 2, 6, and 10 they will be oppositeeach other, creating a static sonority on every other beat. The three-notesonority will only be in unison at phases 0 and 6. At 6 the interweavingof the unison E-B-D outline with the recurring Ff-C} dyad will separatethe two sonorities in th e clearest possible way.Another feature of phases 2, 6, and 10 follows from the structureof the pattern. Since the three-note sonority is stated exactly twice duringthe p attern , and since in phases 2, 6, and 10 an F | will always be oppositea C | (thus neutralizing the duple structure), these phases will consist of


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Reich's Piano Phase 49 7a repeated six-beat composite pattern. This will always happen with acanon at a distance of half the length of the pattern, but it is unusual atother distances.Phase 5 presents a startlingly unexpected situation, repeating dyads.But this is also a direct consequence of the patterns structure. It resultsfrom the fact that in the original pattern two-note successions startingat note 1 are reversed starting at note 5 (see Ex. 3). This in turn followsfrom the displacement, in the second half of the pattern, of one sonorityin relation to the other. Phase 5 is perhaps less surprising in itself thanin the way it emerges during the phasing process, and we will return to it inthat context

Ex.3.

All the musical cards are now on the table. We have a rigoro usly definedsystem, a process that is continuous and free of external intervention forexpressive, formal, or other aesthetic reasons. Where, then, are themysteries? They are in fact numerous and stem in part from the fact thatwhile the process is continuous, our perception of it is not. The listeneris presented with a rich array of possibilities out of which he/she mayconstruct an experience of the piece.The events that constitute the real musical material of Piano Phasemay be divided into those that occur within a stable situation and thosethat arise in the course of phrasing. The first include composite subpatternsand reconfigurations; alternative accentual or metric interpretations ofthe material; and the submerging and reappearance of the original pattern.They may seem to impose themselves on the listener; or the listener mayactively cultivate them, deliberately focusing on a particular reading oreven going back and forth among several alternatives within a singlesituation. Events during phasing concern when and how the changefrom one phase to the next is perceived, as well as with the nature of thechange.The first option is presented within the pattern itself. The patternstructure described earlier could have been applied to any three-note andtwo-note groups. One aspect, however, is specific to the actual pitchesselected. Because of the gap between Ff and B, the pattern tends to divide


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500 The Musical Quarterlyconfiguration begins to coalesce, usually well before the instrumen ts actuallysynchronize again. There may be considerable variance in the listeningexperience from one individual to another and from one hearing to another,in how the exact moment of changes is perceived. It is even possible, withpractice, to choose to retain the old pattern a bit longer or jump to thenew a bit sooner. And during the intermediate stage it is briefly possibleto alternate between hearing and not hearing the pattern. But as soonas one hears the high-low two-voice division of phase 2, whenever thatmay be and whether inadvertently or deliberately, th e old pattern is irre-trievable.The transitions between phases vary in both content and characterdepending on the nature of the preceding phase, the following phase, andthe composite double-time melody formed at the midpoint of phasing.I will only examine one other transition, from consonant to dissonant:phase 4 to phase 5.Phase 4 contains a highly polyphonic two-voice texture. But becausethe F}'s and Cf's are in unison, it is also possible to discern the originalpattern and perhaps even the canonor at least to focus on either of thecanonic voices. In phase 5, as in phase 1, one can hear a rough paraphraseof the pattern; but any more complex structures are overshadowed bythe insistent repetition of the dyads. The progression from consonantto dissonant is then, strangely enough, one of textural simplification. Thekey to the phasing from 4 to 5 is the separation of the unison Ft's andC$'s into repeated notes (see Ex. 9) and their recombination to form therepeating dyads. The repeated notes permit us to follow the phasing processmuch more easily than in some of the other transitions. A good way isto focus on either the high or low voice in phase 4 and follow its progress.

Ex.9.

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An additional area of potential material in this music is opened upby the nature of meter. In much of the music of pattern repetition, meteris largely a qua ntitative factor; one hears that a figure repeats after so manybeats, but there is no functional downbeator several accents may competefor primacy. (I have heard musicians in Reich's ensemble speak of thedifficulty, in performing his music, of "finding the 1.") This non-hierarchic


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Reich's Piano Phase 501meter helps to propel the music forward by eliminating the heavy articula-tion of an unambiguous metric accent. In Piano Phase the pattern itself isfairly unambiguous, but once, phasing begins the me tric situation becomesmore complex. Then it is quite likely that either momentary inattention orthe emergence of a new subpattern will result in a metric reorientation. Evena reversal of strong and weak beats is possibleespecially in odd-numberedphases, where harmonic alternation is absent. Example 10 shows a metricreorientation of phase 3.

Ex. 10.

One may adopt one of several strategies as listener, from passive toactive. The former seems advisable when this music is first heard. Laternew or m ore rem ote possibilities may be sought through metric reorientationand other procedures, including a selective focusing on certain notes andignoring some others. Example 11 shows a pattern derived from phase 2.The d otted line represents the original barline.Ex. 11.

In "Music as a Gradual Process," Reich speaks several times of the "im-personal" quality of the events in his music. In fact the experience oflistening to Piano Phase greatly resembles observing a gradual process innature. Especially comparable is the appearance of discontinuities. Forexample, several such phenomena mark the final stages of a total solareclipse. Here is a description from 1836 by the British astronom er FrancisBaily of what came to be named "Baily's Beads":When the cusps of the sun were about 40 asunder, a row of lucid points, like a stringof bright beads, irregular in size and distance from each other, suddenly formed roundthat part of the circumference of the moon that was about to enter on the sun's disc.


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50 2 Th e Musical QuarterlyIts formation, indeed, was so rapid that it presented the appearance of having beencaused by the ignition o f a fine train of gunpowder.3In the music, discontinuity is of several kinds. During phasing the ear willidentify certain discrete landmark situationsthe splitting of a unison,the doubling of tempo at the midpoint. Even though it is apparent thatthese have been arrived at gradually, the ear identifies them within onlya narrow margin of error, and this results in a feeling of abrupt change.Sudden perceptual shifts occur when phasing has progressed to thepoint where one configuration is no longer viable and is replaced by another.In such cases the discontinuity is purely perceptual, the actual changebeing merely one of degree. As we have seen, perceptual shiftsvoluntaryor involuntary-also take place in the total absence of change in the music.The likelihood of such shifts, which are akin to figure-gro und reversal, in-creases in proportion to the degree of ambiguity of some aspect of themusic.I have suggested that the unison phase of Reich's work has specialsignificance, and thus it is appropriate to end with a brief look at its returnat the conclusion of the phasing process. A second event associated witha solar eclipse provides a striking parallel to the return to unison. Themoment of total eclipse is notable for the sudden appearance of the solarcorona, which at all other times is masked by the sun's brightness. Similarly,the reappearance of unison in Piano Phase is such an event because, asthe pattern emerges and finally locks into phase, we are reminded that,however obscured, it has been there all along.

1 Quoted in Agnes Cleike, A Popular Hixtory of Attronomy during the Nineteenth Century(London, 1902), p. 61.

pattern structure and process in piano phase

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