Improving the practice and performance of contemporary music

General Considerations

text written spring 2015 by Tom De Cock
all examples on this page are published with permission of collection Famille Xenakis. DR. and may not be copied unauthorized without permission.

Formal Analysis based on narrative structures

Certain musicologists and researchers that have been analyzing works by Xenakis approach the formal aspect of his compositions as being constructed by simple juxtapositions (1). It is true that the majority of the works (2) at first sight have a “collage” style of writing but we believe we have to agree with Anne-Sylvie Barthel-Calvet who states in her thesis “Le Rythme dans l’oeuvre et la pensée de Iannis Xenakis” (3) that Xenakis’ works have to be analyzed by the use of “narrative structures” as described in the work of M. Grabocz (4).

The feeling a listener experiences while listening to Xenakis’ music is certainly not eclecticism or incoherence. On the contrary, this music possesses and distributes a sort of tribal coherence that leads us to the thinking of Barthel (5) and Grabocz.

Material borrowed from former pieces

The preparatory sketches we found at the archive currently curated by Mâkhi Xenakis show clearly that Xenakis cites himself by “borrowing” or “copying” parts of former pieces or at least the musical idea behind those parts. In the following chapters we will see clear examples of this “borrowing” in both Rebonds and Okho.

Tempi Alterations

While examining the sketches and manuscripts that have preceded “Rebonds” (1987-’89) and “Okho” (1989) we remarked that Xenakis meticulously calculated the tempi in Okho and that these calculations have repercussions on the interrelations between these different tempi. We also remarked that the tempi were altered, probably after having intense mail conversations with trio “Le Cercle”, to whom the piece was dedicated (the image below displays a letter of Jean-Pierre Drouet to Xenakis asking to avoid the use of excessive speed in the score). Nevertheless the tempi relations remained quasi untouched, proving again the coherence between the different parts of the piece inducted by the composers calculations. In our discussions with Barthel, it became clear that Xenakis always started from the actual duration in minutes and seconds and then calculated the “musical tempi” to translate this into musical language.
In the first sketch of Rebonds B, the tempo is marked as 80 for a quarter note (This is probably the tempo used in Oresteia, see below). This initial tempo was changed in the edited version to 60. This probably had to do with playability. As mentioned above, the original tempi (eighth notes equal: 132-60-88-72-100-80) of Okho were altered (in the final version eighth notes equal: 120-56-80-66-92-70), probably after rehearsals with trio “Le Cercle”. Since the last part of Okho was almost copied literally from Rebonds A and the tempo was brought down afterwards for playability reasons, it is most likely that Rebonds may also be played at tempo eighth note equals 70 instead of 80. This makes the piece a lot more playable than the edited version of the piece.

Choice of instruments

For Okho we suggest to use traditional African rope-tuned djembes. Of course the more modern drums of companies like Remo, Latin Percussion or Meinl are easier for daily use and tuning, and often the skins last longer due to equalized tuning; but the sound of the traditional djembes fits much more the sound idiom that one associates with the force of Xenakis’ music. For performance and presence reasons we also suggest to play the piece standing, using djembe stands or even traditional body straps to mount the djembes.

Xenakis states in the score to use a large African drum (“Une peau Africaine de grande taille”) for the bass note interjections in the middle of the piece and for the very last note of the piece. We suggest using a concert bass drum with natural skin heads. The model we used for the recording was a 28-inch Dicke Bertha by Kolberg Percussion with goat and calf heads on the respective sides (6).

Many people try to make one general setup for Rebonds A and B. We however find that due to the difference in composition strategy for both pieces it is more appropriate to use separate setups for both pieces. For Rebonds A it is logistically difficult to incorporate two large concert bass drums into the setup. Therefore we take one concert bass drum for the lowest instrument and take a large tom of 16 or 18 inches as the second bass drum. To maintain the division of the instruments Xenakis states in the score (2 bass drums, 3 toms and two bongos), we make sure the skins and the tuning of the two instruments that serve as bass drums are of the same type and idem dito for the toms and the bongos. It is strongly advised to use natural skin heads on all instruments. We use goatskins from Altenburger Pergament und Trommelfell (7) that are pre-mounted on aluminium rims for easy use on all the toms. The bass drum we used is the same as the one used for Okho. We asked Pierre-Francois Resta to design hard rubber mallets with a thicker rattan shaft to add sufficient weight to the mallet. Rubber mallets are advised for Rebonds A to take out the harsh attack of wooden mallets and to make the playing sound almost like a tabla player.

The same differentiation in skins and tuning applies to the setup of Rebonds B. As a bass drum we used a 16-inch tom to reduce the size of the setup, but tuned the skin very low to make it sound like a bass drum. Both plastic heads like a Remo Power stroke 4 (8) or heads from the Aquarian Drumheads Vintage Series (9) or calf or goatskin heads can be used. The calf head option works well in addition to a goatskin head on the tom.

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Boris Müller, an excellent percussionist and instrument innovator from Germany, designed the woodblocks we used. They are solid French Oak blocks with a slit that covers the entire surface of the block, which makes controlling the playing spot much easier. Boris designed a set of six of these blocks with a tuning of C-Eb-F#-A-B-E. We alter the use of the five highest blocks with the use of the five lowest for Rebonds B. He also designed special mallets with carbon handles that greatly facilitate the pianissimo rolls on the woodblocks.

Approach to practicing polyrhythms

Due to the extreme speed of the polyrhythms in Rebonds A and Okho, especially the 4 over 3 in a one 16th duration, we believe that a different kind of approach is necessary in studying these polyrhythms to maintain the precision of the rhythms when performed at tempo. The tendency of these polyrhythms when played at tempo is that they become a sort of single stroke roll, without preserving the edgy character of the 4 over 3 rhythm. Therefore, we advise to practice these rhythms slowly in the way it is displayed in the figure below and to gradually speed this exercise up until the performance tempo is reached. The sounding result will be much closer to an actual 4 over 3 than when practiced in a traditional rhythmic way. This is due to the fact that the notes that lie closest to each other always stay close to each other, even when practiced extremely slow. In this way, a certain muscular memory is used to obtain the result that is closest to reality.


Text written by Tom De Cock © Living Scores 2015
  1. BARTHEL-CALVET, Anne-Sylvie, Le rythme dans l'oeuvre et la pensée de Iannis Xenakis, thèse de doctorat. Paris, Ecole des Hautes Etudes en Sciences Sociales, 2000, 2 vol., 700 + 482 p.: p. 497
  2. As stated by Makis Solomos and referred to by Barthel-Calvet: BARTHEL-CALVET, Anne-Sylvie, Le rythme dans l'oeuvre et la pensée de Iannis Xenakis, thèse de doctorat. Paris, Ecole des Hautes Etudes en Sciences Sociales, 2000, 2 vol., 700 + 482 p.: p. 555
  3. EN: “Rhythm in the works and the mind of Iannis Xenakis”
  4. GRABOCZ M., “Les trois modes de la narrativité en musique” in BARTHEL-CALVET, Anne-Sylvie, Le rythme dans l'oeuvre et la pensée de Iannis Xenakis, thèse de doctorat. Paris, Ecole des Hautes Etudes en Sciences Sociales, 2000, 2 vol., 700 + 482 p. pp. 554-557
  5. BARTHEL-CALVET, Anne-Sylvie, « La fin d’œuvre chez Xenakis : enjeux narratifs », La fin d’œuvre en musique : sens et significations, entre création et réception, Grégoir Caux & Mathias Roger (éds.), Sampzon, Delatour, 2013, p. 73-82
  6. Kolberg Percussion gmbh, Grosse Trommel “Dicke Bertha”, 2015 (
  7. Altenburger Pergament und Trommelfell gmbh, 2015 (
  8. Remo Inc “Powerstroke 4”, 2015 (
  9. Aquarian Drumheads Inc “Vintage Series”, 2015 (