Distribution of the sections
Dialogue de l'ombre double is divided into thirteen sections alternating between live and pre-recorded parts:
- Live clarinet: The six Strophes (clarinette/première).
- Pre-recorded clarinet: Sigle Initial, Sigle Final and the five Transitions (clarinette/double).
These sections are structured as follows:
- The *Sigle Initial* and *Sigle Final* are exclusive to the pre-recorded clarinet, serving as the piece’s structure..
- Internal development: Strophes and Transitions alternate, creating a constant dialogue between the two clarinets.
Parallel Versions
Boulez designed two versions of the piece:
- Version aux chiffres romains: The sections are arranged in a regular way.
- Version aux chiffres arabes: The pieces are arranged in an irregular order.
Correspondence between versions of Dialogue de l'ombre Double.
The structural flexibility reminds other compositions by Boulez, such as Domaines or the Third Piano Sonata, where the performer plays an active role in the organisation of the material.
Spatial configuration
Spatialisation is a key part of Dialogue de l'ombre double, making the piece feel like it has two parts. Boulez creates a sound world where the live clarinet and its recorded "shadow" constantly interact, making it hard to tell if the clarinet is there or not. This effect is achieved through a complex setup of speakers, precise positioning, and real-time control of sound movement.
Loudspeaker Configuration and Performer Placement
Boulez says that the clarinettist should stand in the middle of the stage, with six loudspeakers set up around them. These speakers play the recorded parts of the clarinet. This means that the sound from the live clarinettist and the recorded clarinet parts can be mixed together perfectly. In normal concert halls, it is sometimes not possible to spread the sound around in this way, so different set-ups are used to make the same effect.(IRCAM, 2023)
Sound Trajectory and Movement
Spatialisation in Dialogue de l'ombre double creates an evolving acoustic space where sound moves continuously:
- Continuous motion: This is when sound moves slowly from one speaker to another, which makes it seem like it's moving through space. For example, in Transition de III à IV, the clarinet sound moves around the speaker setup, creating a circular motion that speeds up over time.
- Discontinuous motion: This is when there are sudden jumps between speakers, which create contrast and a fragmented effect. This happens when fast ornamental figures quickly move from one speaker to another, breaking the sense of sound moving in a straight line (Noheda Tirado, 2014, p. 45).
Technological Considerations and Modern Adaptations
When Dialogue de l'ombre double was made, they used analogue equipment to process and mix the sound. Nowadays, performances often use digital spatialisation tools that allow for even more precision and flexibility. Advanced software now lets you make real-time adjustments to speaker placement and dynamic movement of sound, so it still follows Boulez's vision but can adapt to modern performance conditions (IRCAM, 2023).
Impact on Perception and Audience Experience
The way that the sounds are placed in "Dialogue de l'ombre double" is more than just a technical issue: it is a key part of how the piece is performed. By using surround sound, Boulez changes the way we listen to the piece, making us use our space and move around.The mix of fixed and mobile sound sources makes it seem like the music is coming from different places, which changes how we feel about the space. This new way of using sound has had a big effect on electroacoustic music ever since, showing that Boulez was one of the first to be interested in music that uses space.
Sound Movement
Spatialisation generates two types of sound movement:
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Continuous: The sound gradually moves from one speaker to another, as in Transition de III à IV, where it imitates a circular motion that progressively accelerates.
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Discontinuous: The changes between speakers are abrupt, as in the Transitions that employ ornamental notes in forte, contrasting with soft trills that remain in all speakers (Noheda Tirado, 2014, p. 45).
In order to develop an interpretative approach, one must first analyse what are the main elements in the structure of the music in order to create a coherent musical idea. The compositional technique of the composer makes a conventional analysis difficult, although Boulez works with a series of heights that is continuously transformed by techniques such as rotation, transposition, expansion and proliferation. He does not employ strict serialism, although he does organise the material around a basic series.
Sigle Initial
The first section, used at the start of the piece, is the same in all versions. The sounds are arranged in four phases, depending on the number of speakers sounding at once. First, there is one speaker (bars 1-21). Then, there are combinations of two speakers (bars 21-38). After that, there are groups of three speakers (bars 39-43). Finally, all six speakers are activated (bars 43-59). The volume of the speakers stays the same during this process, and each entry is one of the 26 irregular phrases in the piece.In the last phrase (number 27), all the speakers are turned off at the same time, which marks the end of the piece.According to Andrew Gerzso, Boulez thought of this progression as a metaphor for the gathering of Luciano Berio's friends at the first performance of the work, which was dedicated to his sixtieth birthday.
The music in this section is repetitive, with a limited dynamic and tonal range, and brief sound fluctuations, including crescendos down to mezzo-piano and quickly pianississimo. These fluctuations allow the phrases to blend naturally as they pass from one speaker to another.The structure of the phrases is irregular, and the chromaticism, together with the indication précipité ('rushed') at the end of the phrases, serves to create a sense of constant momentum. The initial tempo is marked at 196/200 beats per minute, but this gradually decreases as more speakers are added, reaching 160 bpm in the final phrase.The clarinet part is written in the range of A3 to E3, the lowest register of the clarinet in B flat, which makes the soft notes sound even softer. Each phrase ends with a descent to E3, the lowest note, which creates a unique percussive effect.
Despite the fact that the piece is limited in its range of notes and uses the same material repeatedly, the overall sound is not stable in terms of tonality. This is because of the chromaticism and the rhythmic and dynamic fluctuations, which together create a complex texture that prevents the ear from focusing on a single tonal centre.If the tempo were slowed down and the spatial effects were removed, the recurrence of E3 at the end of each phrase would acquire more evident weight, reinforced by the use of accelerando. But in the original piece, the combination of the density of the music and the spatialisation makes it hard to hear the tonal centre.
The lighting is very important in setting the scene. When the clarinettist enters the stage during the Initial Sigle, the pre-recorded track should be playing, with the lighting focused on the sound box. This gives an idea of how the piece will progress. During the piece, the lighting changes between two states. First, the performer is fully illuminated, and then the focus is on the sound box. This shows the clear difference between the clarinet/premiere and clarinet/double.
The recording of 'Initial Sigle' shows the microphone at 0.8 metres from the clarinet. This is the shortest distance in the piece, and it has no digital or piano reverberation. This creates a 'close and natural' sound, as Gerzso says. This part, which is the same in both versions, is very important because it creates the sound and structure that make the rest of the piece make sense.
The last bars of the first part of the piece are played over the start of the first section, but with changes that go against the previous phrase patterns and appear differently in each version. Sometimes, the start of the new section sounds natural and smooth, as if it just came from the previous section. In other versions, the first section ends more obviously before the next part starts. Boulez changes the last bars of the prerecorded tracks in each version, but the solo clarinet (clarinette/première) stays the same.These short changes in music allow for adjustments in lighting, which gradually gets more intense at the start of each Strophe and less intense at the end, until the Final Sigle.
Strophes
Boulez makes the transition from I to II with small trills and tremolos, always soft (mezzo piano or less). The trills are mostly semitones, and the tremolos move between major and minor thirds, making the sound feel unstable. But sometimes, there are loud (forte) accents with small notes before them.
For spatialisation, the sound comes from all six speakers at mezzo piano. But when the loud accents happen, one speaker becomes stronger, then goes back to normal. Andrew Gerzso calls this a 'foreground/background effect' because the loud parts stand out. In the next transition (II to III), the clarinet holds an F5 note, then moves down to E flat4 before the next part starts. The piece has no key, but this F acts like a central note until the climax (bar 17). Boulez asks for a smooth and meditative sound, without strong rhythm. The sound must feel 'very distant,' so digital reverb is 1.8–2.0 seconds, and the microphone mix is mostly indirect (90%). The recorded clarinet sounds like a shadow, with all six speakers playing it. The volume grows, then fades, in contrast to the last section.
In Strophe III, Boulez slows the tempo a lot (crotchet = 34/35), making this part much longer. Here, the clarinet plays multiphonics by using more air pressure in the low register. These notes sound unstable and change in volume. Sometimes, there are loud (sffz) bursts, which quickly drop to piano. Even though these bursts fit the pulse, they make the rhythm feel unclear because the attack is fast, but the sound fades slowly.
In the next transition (III to IV), the structure is based on D4 and C4. D4 brings stability, but C4 makes movement. Trills in whole-tone and semitone add instability. Fast sixteenth-note lines get longer and lead to an acceleration (crotchet = 184). The sound moves around the speakers in a circle, following the tempo. Gerzso warns that if it moves too fast, it will feel static. In the Roman numeral version, this transition is in the center, making the piece feel circular.
In Strophe IV, the live clarinet and recorded track mix fast sixteenth notes, keeping a constant tempo. Boulez does not change tempo or rhythm but uses articulation, dynamics, and melody to create interest. Whole-tone trills appear here for the first time in the piece. In the next transition (IV to V), fast sixteenth notes and grace notes appear in different dynamics. Gerzso calls the spatial effect a 'zigzag pattern,' meaning each phrase plays in a different speaker in an irregular way, making the sound feel like it moves randomly.
In Strophe V, Boulez uses short phrases of crotchets, always with grace notes before them. The echo effect comes from strong changes in dynamics and frequent slowing down (rallentando). Piano reverb makes the clarinet sound last longer without getting lost in the texture.
The transition from V to VI has three main elements: Light tremolos, very loud staccato notes and fast jumps in irregular groups.
It looks like these elements repeat in a pattern, but Boulez changes them slightly to create contrast. The tremolos and jumps are background sounds, while the loud staccato notes stand out.
In the last part (Strophe VI in the Roman numeral version, Strophe V in the other), the intensity stays high, with fast notes and many fortissimo F6s. In the last bars, the tempo slows, and there is a mix of frullato and legato phrases before the final section (Sigle Final).
Boulez ends with a fortissimo E3 with frullato, similar to the beginning of the piece, creating a full-circle structure.
Final Sigle
The final sigle in both versions of Dialogue de l'ombre double is almost the same but in the version with Arabic numerals the first bars are a bit longer to help the transition which also affects the numbering of the bars in the spatialisation and lighting instructions
The final section has two clear parts the first bars 1 to 63 has more action while the second bars 64 to 139 creates a feeling of distance the music is very difficult to play because of big jumps between notes fast articulation and constant dynamic changes.
In the first 24 bars Boulez writes two contrasting instructions agitated but murmuring and like a sudden interjection creating tension and surprise then between bars 25 and 63 the rhythm becomes even more unstable with sudden meter changes and tempo variations crotchet equals 116 to 152. The spatialisation is important in this section as the speakers slowly increase in volume from mezzo forte to forte and the digital reverb grows from 1 over 10 to 10 over 10 making the clarinet line feel more intense.
Even though this part is prerecorded the live clarinettist clarinette première still plays at the end in bar 64 or 66 in the Arabic numeral version the performer holds a very soft pianissimo D6 until the end about ten bars before they must turn 180 degrees and stay like that this movement is not only theatrical but also makes the sound feel more distant
In the second part of the Final Sigle Boulez highlights the live clarinet while the prerecorded clarinet clarinette double keeps a repetitive pattern the spatialisation changes as the six main speakers turn off one by one until only a seventh speaker remains placed behind the stage playing the final part of the recording.
The feeling of distance is also created by how the sound is captured as the direct microphone gradually fades out leaving only the indirect microphone and reverb at the same time the stage lighting dims as the live clarinet enters ending the piece in an atmosphere of disappearance.
The final sigle contrasts with the first sigle as the beginning of the work has energy and leads into the first strophe but the final sigle feels like a chaotic ending as if the piece represents the guests of a gathering slowly leaving possibly a reference to Berio’s friends at the premiere of the piece.