Spectralism: A Short Introduction to Spectral Music

Source: Spectralism - a short introduction to spectral music, Liam Carey, 11:49, uploaded 2020-06-28, playlist index 499.

Liam Carey made this short primer for his students. He focuses on the French and German schools of spectralism and uses four works to show how composers turn the frequency content of a sound into material for harmony, orchestration and timbre. The video dates the term spectralism to 1979, whilst also pointing out that it has since been applied to a range of composers.

Overtones, spectra and timbre

Carey starts with a single clarinet note. Its lowest frequency is the fundamental. The higher frequencies are overtones, and the group of frequencies heard together forms the spectrum. The spectrum also helps explain timbre, the quality that lets us distinguish instruments playing the same note.

The demonstration compares a trumpet with a flute. The trumpet has a fuller spectrum with many high overtones, which gives it a rich and bright sound. The flute has fewer high-frequency components and sounds purer. Carey uses this difference to introduce a main feature of spectral music: the boundary between harmony and timbre becomes difficult to keep in place. A chord can be heard as a colour or sound object, whilst a tone colour can become the material from which harmony grows.

From a trombone spectrum to a sound object

The first musical example is Gérard Grisey’s 1975 work Partiels. It opens with a single low trombone note. Carey explains that Grisey takes the spectrum of this note and distributes it across the rest of the ensemble. The result occupies an uncertain place between a chord and a timbre, an idea he supports with a description from composer Julian Anderson.

Carey distinguishes this from orchestral synthesis that tries to recreate a trombone. Every instrument in the ensemble has its own spectrum, so the ensemble cannot produce an identical copy of the original instrument. Grisey makes an intensified, almost hyper-real version of the initial sound object. The original tone supplies the material, while the instruments reshape that material through their own acoustic properties.

Electronic spectra and ring modulation

Carey then turns to Tristan Murail’s Les courants de l’espace. Murail uses an electronic instrument, the ondes Martenot, in place of an acoustic sound source. The instrument begins with a pure sine wave. The strings answer it by playing harmonics, creating a call-and-response between the electronic line and the ensemble.

The ondes Martenot signal passes through a ring modulator. The process adds sum and difference frequencies to the original sound, which produces a more complex spectrum. The ensemble then plays the frequencies that emerge from that process. The composition treats electronic transformation as an orchestral source: the sound is analysed, changed and redistributed as musical material.

Extended technique as spectral change

Kaija Saariaho’s Sept Papillons for solo cello supplies a more direct instrumental example. Saariaho asks the cellist to play sul ponticello, with the bow close to the bridge. This playing position amplifies the instrument’s overtones and creates what Carey calls a spectral harmony.

The technique changes the cello’s spectrum without changing the instrument itself. The resulting harmony depends on the colour of the sound, which brings the video back to its earlier claim about the unstable boundary between timbre and harmony.

Microtones and the harmonic series

Spectral composers also use microtones, intervals smaller than a semitone, to notate overtones more accurately. Carey shows a harmonic series built on C and points out that several of its pitches sit between the notes of equal temperament. The seventh harmonic lies roughly a third of a semitone flat, whilst the eleventh lies roughly half a semitone flat.

This gap between the harmonic series and standard tuning leads some composers to use extra accidentals for quarter-tones and sixth-tones. Georg Friedrich Haas’s String Quartet No. 2 makes the idea audible through both tuning and playing technique. The cello begins with a low C and moves its bow towards the bridge to bring out the overtones. The viola and violins imitate and sustain those frequencies. Haas numbers the overtones in the score so the players can place them in relation to the cello’s low C fundamental.

A continuation of older harmonic ideas

Carey closes by connecting spectralism to earlier music. He treats harmony based on overtones as an old idea, from the use of perfect fifths in medieval organum through the later establishment of the triad. His account places spectral composers further up the harmonic series, where the pitches and colours that conventional harmony leaves implicit become explicit material.

The four pieces in the video form an introduction rather than a complete history. The narration gives the 1979 date and the historical connection without a supporting bibliography, and it concentrates on the French and German schools whilst acknowledging that spectralism has been applied more widely. Carey recommends Jonathan Harvey, Claude Vivier, Anna Maria Avram, Emily Hall and Julian Anderson as further listening.

Further listening / references

• Gérard Grisey, Partiels.
• Tristan Murail, Les courants de l’espace.
• Kaija Saariaho, Sept Papillons.
• Georg Friedrich Haas, String Quartet No. 2.
• Jonathan Harvey, Mortuos Plango, Vivos Voco.
• Claude Vivier, Lonely Child.
• Anna Maria Avram, Swarms.
• Emily Hall, Ode to the Pylon.
• Julian Anderson, The Discovery of Heaven.