Sequitur XII

Composed in 2009 and dedicated to harpsichordist Maja Mijatović, Sequitur XII is part of Karlheinz Essl's Sequitur cycle, a collection of fourteen works for solo instrument and live electronics composed between 2008 and 2010. Inspired by Luciano Berio's Sequenze, the cycle explores the unique technical and timbral possibilities of each instrument while creating an interactive musical dialogue between performer and real-time electronic processing.

At the heart of the project is the Sequitur Generator, a custom software environment developed by Essl in Max/MSP. Rather than accompanying the performer with pre-recorded sounds, the software continuously analyzes the live instrumental signal and generates an evolving eight-voice electronic canon derived entirely from the performer's sound. Because the electronic processes respond dynamically to the live input, every performance is unique.

In Sequitur XII, Essl radically reimagines the harpsichord by moving beyond its traditional keyboard technique and characteristic plucked sound. Instead, the performer explores the instrument through rubbing, scraping, tapping the soundboard, directly exciting the lowest string, and manipulating a nylon fishing line attached to the instrument. A contact microphone captures even the smallest vibrations, allowing acoustic gestures and electronic transformations to merge into a single hybrid sonic environment.

Although the score is precisely notated, the interaction between performer and electronics introduces an element of unpredictability. The electronic performer shapes the live processing in real time, continuously responding to the harpsichordist's gestures through parameters such as transposition, tremolo, frequency shifting, ring modulation, flanging, reverberation, and spatialization. This constant dialogue transforms the instrument into what Essl describes as a "meta-instrument", where acoustic sound and digital processing become inseparable (Benedetto Boccuzzi, 2026).

In this composition, the harpsichord is played in a highly unconventional manner. Except for the end of the piece, no keys are touched. Instead, the sound board and the lowest string of the instrument (1F) are excited in different manners. A contact microphone mounted on the sound board acts like an acoustic lense that amplifies sounds that are normally inaudible. The interaction between the harpsichordist and the live-electronics creates a kind of meta-instrument. Its novel sounds and expressions purposely avoid the typical percussive sound of the harpsichord, which is only heard at the end of the piece as a quotation.

By preparing the instrument with a thin nylon thread, sustained „drone“ sounds can be produced as an antitheses to the needle-sharp and rapidly decaying harpsichord attacks, which György Ligeti tried to overcome in his harpsichord composition Continuum (Karlheinz Essl).

In Anknüpfung an die berühmten Sequenze von Luciano Berio für virtuos gespielte Soloinstrumente unter Erweiterung ihrer spezifischen Klangmöglichkeiten arbeitet Karlheinz Essl seit 2008 an seinem Sequitur-Zyklus, der diesen Ansatz unter Einbeziehung von Live-Elektronik weiterverfolgt: Ein genau ausnotierter Solopart wird über ein Mikrophon in eine eigens entwickelte Software eingespeist, das in Echtzeit einen Kontrapunkt generiert. Sequitur XII, das für Maja Mijatović entstand, gewinnt seinen klanglichen Reichtum paradoxerweise durch einen Verzicht: Fast über die gesamte Dauer werden keine Tasten angeschlagen, um den typischen Cembaloton zu vermeiden. Stattdessen werden die Klänge fast ausschließlich auf unorthodoxe Weise erzeugt: Durch Streichen, Schaben und Klopfen am Resonanzboden, durch die auf vielfache Weise direkt zum Klingen gebrachte tiefste Saite – unter anderem durch einen Nylonfaden, der an ihr befestigt ist und langgezogene Sounds ermöglicht. Jenes Kontaktmikrophon, das am Resonanzboden befestigt ist, "wirkt dabei wie eine akustische Linse und verstärkt Klänge, die sonst unhörbar bleiben würden" (Essl). Wenn dann ganz am Ende doch noch ein repetierter, regulärer Cembaloton erklingt, wirkt dies wie ein verfremdetes Zitat (Daniel Ender).

Score

The score of Sequitur XII can be downloaded for free. Please note that the music is protected by copyright.

Videos

Literature

Nissim Schaul, Nouvelles technologies, anciens instruments: le clavecin et la mixité.
Master thesis, Université Paris VIII, Département de Musique (Paris 2013), p. 29-32.

Updated: 3 Aug 2026