Karlheinz Essl

Portrait KHE

Sequitur XIII

for extended piano and live-electronics (two players)

Dedicated to Tzenka Dianova

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Karlheinz Essl: Sequitur XIII (2010)

Performed by Tzenka Dianova (piano) and Karlheinz Essl (live-electronics)
Klosterneuburg, Essl Museum (9 Jun 2010)


Sequitur is a series of 14 compositions for various solo instruments and live-electronics written for outstanding soloists. Somehow it can be seen as a reference to Luciano Berio's famous Sequenze cycle of solo pieces which focus on specific playing techniques of the respective instrument. Essl's Sequitur cycle includes pieces for orchestral instruments like flute and violin, but also for voice, electric guitar, toy piano or kalimba.

All Sequitur compositions use a software written in MaxMSP which creates an electronic accompaniment from the instrument’s live input; the player is confronted with his own playing, and this creates a situation like moving in a house of mirrors where the identities becomes blurred. The Sequitur software generates a complex canon on the fly, the temporal structure and density of which being controlled by random operations. This yields different results every time the piece is performed. Although following a precisely notated score, there is always a good portion of surprise for the musician which emphasizes his awareness and attentiveness.

In Sequitur XIII, various resonance phenomenons of the piano are investigated. At the beginning, muted keys in the highest and lowest register are used to excite diffuse resonances. Later on, an EBow comes into play in order to focus those resonances towards the middle c which is more or less always present to certain degrees. This pitch is also the anchor point of three different harmonic scales based on odd-numbered overtone series:

Harmonic material of Sequitur XIII

Deriving from this harmonic principle, flageolets (always odd-numbered with 3rd or 5th overtones) are introduced later.

Furthermore, I am also using all three pedals of the piano and certain keys which are depressed silently in order to create sympathetic resonances. The virtuosity of this piece is not found in the polyphony of voices, but in the polyphony of structural components which - by interacting with each other - form a common "sound" together.

The electronics create a complex canonic structure from the live input of the piano which includes random procedures in order to subvert the determination of the canon, and also modifications of the harmonic structure: either by amplifiying or distorting certain spectral components, but also in creating microtonal pitch shiftings. This is organised in a sequence of pre-composed cues that the a second player evokes by hitting the space bar of the computer at certain times, as notated in the score. The second musician also takes care of controlling the input levels of the microphones (notated in the score by red crescendo / decrescendo signs) and the output levels of the computer-generated electronic sounds which are notated by green crescendo / decrescendo signs.


The full score of Sequitur XIII can be downloaded for free. Please note that the music is protected by copyright. Here is an excerpt of the piece:


Tzenka Dianova and Karlheinz Essl premiering Sequitur XIII
PERILOUS NIGHT - Utopische Klaviermusik
Klosterneuburg, 9 Jun 2010

Víctor Trescoli Sanz and Karlheinz Essl performing Sequitur XIII
Karlheinz Essl: Music for (Toy) Piano and Electronics
Universitat Politécnica de Valencia, 27 Apr 2012

Xenia Pestova and Karlheinz Essl performing Sequitur XIII
The Dark Side of the Piano
University of Nottingham, 4 Feb 2016

Katharina Bleier & Karlheinz Essl performing Sequitur XIII
Arnold Schönberg Center Vienna, 9 Jun 2016

Sequitur XIII with score
Thanks to incipitsify


Maria Kallionpää: Beyond the Piano: The Super Instrument. Widening the Instrumental Capacities in the Context of the Piano Music of the 21st Century
Chapter "3.8 Karlheinz Essl: Sequitur XIII"
Dissertation (University of Oxford, 2014)
Katharina Bleier: Karlheinz Essl: Bows
About Karlheinz Essl's bowing techniques for piano used in Sequitur XIII for extended piano and live-electronics
EXTENDED PIANO - blog (May 2020)

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Updated: 30 May 2021