Ionisation (1930), as we now recognize it, is the first and the most consummate work to explore the structural value of all non-pitch properties of sound without electronic means. It is also unique in Varèse’s output. In Ionisation, more than in any other score, Varèse reveals to an extraordinary degree not only his concepts and techniques but also the profundity and imagination with which he crystallizes (to borrow one of his own favorite expressions) his ideas: in this case, hewn from raw sonic material that offers no definite pitch or known means for development and organization. To analyze Ionisation, then, is to pave the way for understanding all of Varèse’s music.

Observation on the Basic Concepts

The first step in understanding Ionisation’s structure is to analyze Varèse’s choice of instruments. Initially, these instruments can be classified into the following seven categories according to timbre:

1. Metal
   Triangle, anvils, cowbells, hand cymbals, crash cymbal, suspended cymbal, gong, tam-tams, and rim shot (on tarole, snare drum, parade drum, and tenor drum).
2. Membrane
   Bongos, snare drum without snare (Player 8), tenor drums, and bass drums.
3. Snare
   Tarole, snare drum with snare (Player 9), and parade drum.
4. Wood
   Claves, wood blocks, and slapstick.
5. Rattle-Scratcher (Multiple Bounce)
   Sleigh bells, castanets, tambourine, maracas, and guiros.
6. Air-Friction (Varying Intensity)
   Sirens and string drum.
7. Keyboard-Mallet (Tone Cluster)
   Glockenspiel with resonators, chimes, and piano.

All instruments in Ionisation are assigned one or more of the following functions: [1] generating germinal ideas, [2] defining textures, [3] linear elaborations, [4] verticalization of textures, [5] delineating phrases and sections, [6] “modulation” in timbre and register, and [7] providing special acoustic characteristics.

Introduction to the Analysis

Section 1 (measures 1-8): Texture I
While this section is introductory in character, the first four measures serve in fact to define Texture I, which closely resembles the envelope characteristics of a gong sound: attack (tenor drum and bass drums); steady state (gong and tam-tams); growth and decay (sirens, snare drum without snare, and cymbals). Elements from this texture are seldom absent throughout the piece. Thus, Texture I may be regarded as the foundation in Ionisation’s structure, a kind of textural “pedal,” with metal serving as the timbral “center” of the whole piece. Germinal rhythmic ideas in the subsequent measures of this section anticipate later development.

Section 2 (measures 9-12): Texture II
While the parade-drum passage, in a “classical” guise of 2+2 measures, appears to take on the character of a “theme,” it is no more than a succession of typical snare-drum stick techniques. The definition of Texture II largely depends on the other instruments carefully “orchestrated” in terms of timbre and register: bongos/maracas in higher register, deep bass drum/hand cymbals in a lower one, with the first phrase marked off by slap-stick/tenor drum and the second by string drum/deep bass drum.

Section 3 (measures 13-20): Texture III
The close relationship of the three textures of Ionisation is revealed after measure 13, where in quick succession Texture I and II lead on to Texture III, at measure 18. The wood-blocks passage suggests a combination of the parade-drum and bongo motives, “modulated” to by way of tarole in rhythm, timbre, and register. The wood blocks/tarole sonority is complemented by a “rattle” sonority (sleigh bells/castanets/tambourine). Thus, Texture III is assigned to the highest of the three textural registers.

Section 4 (measures 21-37): Linear Elaborations
Section 4 begins a linear elaboration of Texture II in juxtaposition with Texture III. Many diluted sonorities from Texture I are also present (especially after measure 25). The presence of bass drums is however a different matter. It represents a timbral transformation of the instruments (now with wooden sticks) and a change in register of the bongo motive, partly to accommodate Texture III (the parade drum’s register also being lowered by the use of felt sticks) and partly to allow bongos to exchange material with parade drum.

Section 5 (measures 38-50): Verticalization of Textures
Section 5 is a juxtaposition of verticalized sonorities from Textures II and III with linear movements from the same textures (on parade drum/tenor drum and tarole/snare drum). The interlocking chords in rhythmic unison can be identified by the accents and registral changes that create a two-against-three cross-rhythm.

Section 6 (measures 51-55): Return of Texture I
This return is marked by an all-metal sonority (except for the sirens). The bass-drum part is now replaced by a rhythmically much-elaborated part for anvils, which appear in the score for the first time.

Section 7 (measures 56-65): Linear Elaborations
The prominent presence of anvils and the greater emphasis of the “gong” sonority (including sirens) create a markedly different overall texture from that of the other linear elaborations section (Section 4). Fundamentally, Section 7 is an interplay between the metal sonority and variants of Texture III in juxtaposition with Texture II.

Section 8 (measures 65-74): Culmination of Elaborations
The three measures beginning at measure 69 are a brief culmination of the simultaneous elaboration of all textures initially presented at measure 23. The linear combination of bongos and bass drums clearly emphasizes a close relationship already noted.

Section 9 (measures 75-91): Conclusion
This section is much in the nature of a summation as well as a coda, consisting of sonorities of all three textures. It begins with the all-metal sonority of Texture I, much amplified by the appearance of piano, chimes, and glockenspiel (all used as if they were instruments of indefinite pitch) as well as a deep tam-tam. While the overall texture is climactic, a sense of conclusion is heightened by the fragmentation of the parade-drum rhythm and by the repeated appearance of the cadential figure on wood blocks.

Functions of Instruments and Structure

1. Generating Germinal Ideas
The tenor-drum/bass-drums motive in measure 1 (Example 1) and its expansion in measures 4-6 (Example 2) are germinal both articulatively (that is, in providing groups of attacks) and rhythmically, since the rhythm reflects a natural stick-movement in articulating several drums in a groups, in quick succession and in repeated strokes. Thus, articulatively, this tenor/bass-drum motive not only leads to such obvious developments as the triplets at measure 44 (Example 3) but also to such registral expansions as the bongos part at measure 23 (Example 4) and the wood-blocks part at measure 27 (Example 5).

2. Defining Textures
At the opening, Texture I is defined by the “gong” sonority (on low, sustaining metal instruments), the membrane attacks, and changing intensity on instruments of related timbre (Example 10). The hand cymbals, producing a sustaining sonority, should nonetheless be regarded as part of the group responsible for the changing intensity, since when cymbals are played a 2 there is a discernible amount of fluctuation in intensity.

Texture II is initially defined, at measure 9, by the parade drum, bongos, maracas, deep bass drum, and hand cymbals.

The characteristics of Texture III are provided by the multiple-bounce instruments in a chordal movement against the linear progression of the tarole and wood blocks, which proceeds at a pace doubling that of Texture II. Texture III is also timbrally coordinated, since the sonorities of the two groups are complementary to each other at the given pace.

3. Linear Elaborations
All of the instruments responsible for articulating the linear movement in the three textures (namely bass drums, tenor drums, parade drum, bongos, maracas, tarole, and wood blocks) actively take part in linear elaborations by expanding upon the rhythmic cells identified with the three textures and by serving as rhythmic counterpoint to the bongo motive.

Functions of Instruments and Structure

4. Verticalization of Textures
The vertical aggregate at measure 38 is actually formed of two groups that are differentiated by the two-against-three cross-rhythm, as indicated by the accents. This metric relationship had already been suggested at measure 9, where the maracas, deep bass drum, and cymbals are actually in 3/4 while the parade-drum part is in 4/4; the bongos part is naturally also in 3/4 except in measure 11, where the quarter-rest is elided as the bongos adjust to the phrase structure of the parade-drum part (Example 16).

5. Delineating Phrases and Sections
A number of instruments are assigned the function of delineating the formal structure at various levels. The consistent use of most of these instruments exclusively for articulating the structure at an assigned level approaches the colotomic principle found in such music as the Indonesian gamelan and the Korean hyang-ak.

The triangle is used only to delineate large-scale formal divisions.

The string drum is assigned the function of a cadence-like punctuation marking the end or return of Texture I.

6. Modulation in Timbre and Register
The first instance of a timbral modulation takes place at the conclusion of the initial four-measure phrase, which defines Texture I.

At measure 18 the continuation of the preceding maracas movement on the bass drums effects a sudden reversal in both register and timbre as the tarole raises the register of the snare sonority and ushers in a group of high-pithced multiple-bounce instruments.

7. Special Acoustic Characteristics
The siren produces crescendo and diminuendo characteristically, according to the speed with which the rotating disk is made to turn. With the gradual change in intensity, there is also a minute but discernible change in pitch and timbre. It is perhaps for these acoustic characteristics that the sirens are used in Texture I.

The string drum is the only instrument that shares these acoustic characteristics with the siren. While it complements the siren, it is fundamentally assigned to demarcate Texture I, as has been noted.

The piano, glockenspiel, and chimes are treated as metal instruments that are capable of playing simultaneously at different registers. They are used to enrich the “gong” sonority and to broaden the total range of the metal sonority.

Germinal Rhythmic Ideas and their Functions

1. The Bass-Drum Motive
The initial figure on the tenor drum and bass drums and its expansion at measure 4 represent more of a performance technique than a specific and inviolable rhythmic motive. The idea of a two-note rhythmic cell (either short-long or long-short depending on the placement of accent, or even of equal short values) for moving the sticks from one to another of a group of instruments, and that of a syncopation for repeating strokes on two instruments simultaneously (the sticks having just arrived at those instruments) are as germinal in this score as the specific note-values notated here.

2. The Bongo Motive
The bongo figure at measure 5 is the result of articulating two drums alternatingly rather that using several strokes in succession.

This expanded version of the bongo motive first appears in superposition with the (c) figure cited above, as counterpoint to it, and then proceeds in the next three measures to accompany the parade-drum motive (now on bongo) in place of the original version of the bongo motive.

3. The Claves Figure
The bass drums in measure 5 are the midpoint of a brief timbral modulation to the vertical admixture of timbres at measure 6, as can be seen in Example 9.

4. The Quintuplet
The quintuplet figure introduced in measure 6, as shown in Example 9, becomes an important feature in the wood-blocks part at measure 18 and is repeated on the tarole at measure 27. As the modulatory passage of Section 4 gets underway, the quintuplet appears in the guiro part at measure 31, where it is in retrograde form ( 1 + 2 + 2 instead of 2 + 2 + 1) and without syncopation (as can be seen in Example 26), anticipating the quintuplets at measure 44.

5. The Triplet
The triplet introduced by the deep bass drum in measure 7 participates in demarcating Texture I. Here and at measure 12 the triplet joins the string drum in this function. At measure 23, as all three textures return in juxtaposition to begin the elaboration process, the triplet preceded the bongos/bass drum figure that articulates the tam-tam, as can be seen in Example 25.

At measures 66, 68, and 74, the triplet is incorporated in the rhythm of the chordal phrases in anticipation of the expanded Texture I at measure 75.

6. The Parade-Drum Motive
The parade-drum motive consists entirely of metrically notated ruffs and syncopations, both already suggested by the bass-drum motive. The ruffs are not only used later to expand the parade-drum motive, but also become part of Texture III’s rhythmic scheme in the form of fast repeated notes on the tarole and wood blocks, short rolls on the sleigh bells and tambourine, and grace-notes on the castanets, all of which can be seen in Example 24. The most characteristic feature of the parade-drum motive, however, is the succession of syncopations of varying values at measure 9.

Summary of Structural Principles and Procedures

1. 1. 1. The structural principles of Ionisation are evolved out of the characteristics of the instruments chosen.
      2. A crucial principle is the grouping of instruments of the same family or of compatible articulative and vibratory characteristics so that a group of such instruments (whether manned by one or more players) is capable of changes in register and timbre and yet remains identifiable as a single part or “line.”
      3. All germinal rhythmic ideas are derived from characteristic performance techniques of the instruments for which such ideas are initially conceived.
      4. Although some of the rhythmic cells evolved out of these germinal ideas can be combined into a continual rhythmic passage, the fundamental interest is in timbral and registral combination of such cells to produce identifiable textures.
      5. Although considerable rhythmic counterpoint is employed, conventional contrapuntal procedures are generally avoided. Even when such procedures do appear, their function is to enhance local texture rather than to serve as structural means.
      6. All of the basic textures are interrelated through transformation of rhythmic, timbral, and registral ideas. This contributes to a sense of growth or evolution.
      7. This sense of growth is carefully controlled through a number of means. The choice of instruments for defining the three basic textures indicates a gradual shift of emphasis in register from low to medium to high, as well as a concomitant shift from a “darker” to a “brighter” timbre (bass drums to snare to rattle). This double shift is also present on a larger scale, as is shown in the Outline of Structure. A third conjunct element in the gradual shift from the first to the third texture is the increasing rhythmic activity related to the choice of instruments.
      8. Another means of control is the assigning of special functions to certain instruments for the clarification of structure or to effect modulation in register and timbre.
      9. Dynamics are, in the context of this piece, by and large the means to sharpen the definition of texture and to focus on certain interrelations in the juxtaposition of textures. Nonetheless, the over-all dynamic scheme is clearly correlated with the formal organization of the piece.
      10. The three basic textures interact in superposition and by means of linear elaboration or verticalization. Linear elaboration results in an expanded sonority rather than a mere increase in rhythmic activity. This is achieved by exchange of material or added parts with related timbre and extended register. Verticalization is achieved by superposition of chords from the different textures without sacrificing their identity.

Concluding Remarks

The above are of course only observations, not all of which can be demonstrated as part of Varèse’s planning for the work or details arising out of an intellectualized process. The fact remains nonetheless that these striking interlocking designs in literally every conceivable musical dimension coalesce to such an extent in this score that Ionisation is revealed as a cornerstone of mid-twentieth-century musical development.

According to Louise Varèse, Ionisation is the work that Varèse was most satisfied with and proud of. This is in part reflected in his letter to Carlos Salzedo dated December 17, 1931: “Ionisation (title of my piece for percussion) has turned out well — cryptic, synthesized, powerful, and terse. And, as for the structure: stunning mechanics. What I like most about myself is my modesty.”

By Chou Wen-chung