Karlheinz Essl is an Austrian composer, performer, improviser, media artist and composition teacher at the University of Music and Performing Arts Vienna. His work with computers, as well as a long-term preoccupation with the poetics of serial music, have had a formative influence on his compositional thinking. Karlheinz Essl works in the areas of electronic music, interactive real-time compositions and sound installations in addition to writing instrumental music. Essl performs as an improviser using his own computer-based real time composition environment (m@ze°2) and collaborates with artists such as Agnes Heginger, with whom he had a free improvisation duo for voice and electronics.


Adrián Artacho interviewed him on July 6th, 2021, about his approach to collaborative composition, specifically his long-term collaboration with toy pianist, Isabel Ettenauer, which has resulted in many new works for that repertoire.

Artacho: We are very much interested about the topic of collaboration and how collaboration alters or enriches the process of creating music. I see that you've been collaborating with Isabel Ettenauer for over a decade now, since Kalimba in 2005. And your CD together Whatever Shall Be was released in 2013. So that's a collaboration that stretches over time. I have read you saying that it was also a discovery of the instrument and its possibilities. And as a result of it, there's now a body of pieces for toy piano that would have never happened if you hadn´t taken this interest.

Essl:       Yes.

Artacho: I guess my question would be, in which way did your collaboration, and more specifically, besides the possibilities of the instrument, the feedback that Isabel was able to give you. Did her approach to the instrument change your writing for toy piano in some way?

Essl:       I would like to reflect a little bit on how it started. It was a long process. I came in contact with Isabel 20 years ago at the Essl Museum where I curated a series of concerts. Once she came to me and suggested a program with toy piano music. I gave her the possibility to play a concert there which I really liked. And also the way she's performing on different instruments in a very humble setting. It was not on stage as she was sitting on the floor, surrounded by the audience, and playing all these little instruments. At this time, there was no big repertory for toy piano, but there was this important piece of John Cage, the Suite for Toy Piano that Isabel had in her program, and some pieces that she commissioned from friends and colleagues. Afterwards she asked me: ‘Don't you want to write a piece for me?’ And I said: ‘Well, toy piano. It has so many limitations. I'm not so sure about it.’ In the beginning, I rejected it. After a couple of years, she played another concert with a much broader repertory. And then she came again and said: ‘Karlheinz, what about writing a piece? You sort of promised to me’. I said: ‘Okay, I'm willing to do that but under one condition: I need an instrument. I can't write a piece for toy piano, without having an instrument.’ And she said: ‘Well, you can have one of mine’. She had a lot of instruments and she gave me a big one, the grand piano of Schoenhut (the manufacturer). She delivered it to my studio and I had it there for a couple of weeks.

The first thing I was doing was just playing on the instrument, improvising, finding out things without her. It was just my own encounter with this new instrument where I soon discovered that this is not a piano. It's something very, very different. Something that looks like a piano but doesn't have the whole history of the piano music that we have on the grand piano. This was the first trigger for the piece that I wanted to write for her. A piece that starts very, very simple, and then enriches in a way that the toy piano becomes sort of an orchestral instrument. Most of the pieces that I had heard, except for the piece of John Cage, sounded mostly quite similar, and some of them had a certain childish flavor which I abhor. However, I wanted to use this instrument as a really serious concert instrument for experimental music. And this is the concept behind
Kalimba. It's a piece which is played on the toy piano, but inside the toy piano there is a hidden small loudspeaker. And from the loudspeaker comes an electronic soundtrack that is produced only with eight notes that I recorded on the toy piano. In fact, it was Isabel who recorded them. I invited her and told her about what I had found, and that I want to write a piece based on this very special eight-tone scale which is the only material of the piece. I said: ‘Because you play the piece, I want you to make the recording with only these eight notes’. With this material, I developed the electronic soundtrack which is a sort of micro-tonal canon that exclusively uses these eight notes in several layers with very slight transpositions. And by this, the toy piano sound finally becomes something very dense and large and orchestral.

2005, there was the first toy piano composition competition of the Clark University in Worcester, MA. I submitted Kalimba, and to my surprise it won a prize. Included was a performance, of course, but it was clear that it couldn't be Isabel because another toy pianist,Phyllis Chen, was supposed to play the final concert. So I had to find a possibility for Isabel to play the première of ‘her’ piece before. By coincidence, I was invited to the Komponistenforum Mittersill and I suggested that Isabel would play the world première of Kalimba  and it really succeeded. And then she took the piece into her program and played it dozens of times until now. And this was not the last piece that I wrote, because I was so happy that I had somebody who is interested in playing my music, that immediately I wrote another pieceWebernSpielWerk, which had its first performance by Isabel at the same venue.

Artacho: Kalimba is a very successful piece that has been played again and again.

Essl:       Well, if you look at my list of performances, Kalimba has been played around 200 times until now. Not only by Isabel who played most of the performances. It's really written for her and for her instrument. The playback sound is the sound of her instrument (she always plays it on the same instrument), so when she plays it, it really sounds like it's the same instrument.

Artacho: So, bespoke to the instrument. You mention that she provided the initial recording, those eight notes, and also that the piece written for her was performed by Phyllis Chen in America. Was the notation encompassing enough that somebody else could play using the score alone? Did that change over time as you went on collaborating with Isabel?

Essl:       All pieces that I wrote for her and for others are fully notated (except for Pachinko which is improvisation between a toy pianist and a computer). In fact, Isabel never asked me to write an ‘open form’ piece where she could improvise. There was no question about that. It was clear that I would deliver a fully notated score. Soon afterwards, I discovered that it's very interesting to use the toy piano with live electronics and live sound processing. And Isabel was also very interested, but she had no experience so far. So I told her how to do this. A couple of years laterin 2008I composed Sequitur V for her. This piece uses the live input of a toy piano, which goes through a computer program written in Max, which creates a sort of generative accompaniment in real time. The sound of the toy piano is so-to-speak thrown into a house of mirrors, reflected by various electronic manipulations. Of course, I had to tell Isabel how to do that all. I showed her the right microphone, we chose the computer, the audio interface, the loudspeakers, and then we had a lot of rehearsals in my studio. There she learned how to master the live-electronicsand she became really a professional. Finally, she was traveling all over the world with her toy pianos and with her computer, her audio interface and microphone, playing my pieces. This motivated me to continue our collaboration by writing even more pieces, because I knew if I wrote a piece for her, she would perform it beautifully and often.

Artacho: And I'm guessing that was also fulfilling for her, in the sense that she is kind of commissioning or instigating these pieces to go in the direction that she would like her toy piano to go.

Essl:       In fact, there was never a commission, and there was never any money involved. It was a mutual collaboration between two artists. We also needed each other; she needed me to write a piece, I needed her to play it. But she also commissioned other composers, so it was not exclusive. Our collaboration resulted in very different pieces as I didn't want to compose a similar piece. I always tried to explore new things. Isabel showed me that playing a toy piano also means to maintain the instrument. Sometimes you need to open it and to adjust some things inside the mechanic, using some tools, etc. It was interesting to me to see that you can also go inside the guts of the instrument and start manipulating its acoustic, mechanical properties. And this is where we were making some very interesting experiments together, which resulted later in pieces like Miles to go, which was a piece for four prepared for toy pianos, and also Whatever Shall Be where she plays a lot inside.

Artacho: Which is on the CD Whatever Shall Be...

Essl:       It is on the CD. The good thing is that I had these instruments in my studio as I've bought different types of toy pianos. Frankly, I don't know how many I have, not as many as Isabel (she has lots) but I have at least eight or maybe ten.

Artacho: You just said that at the end of every piece, you wanted to go in a different direction. Would you say that the result, the piece you just wrote for Isabel, is the springboard that leads to the next idea? Or could these pieces have been written separately from each other, without this connection?

Essl:       I don't know. Of course, there is some development, but this is not a linear process. Sometimes it was like building up from an experience, but sometimes it was jumping into something completely new. Once I wrote a piece for music box with punch tape. I made some experiments by composing my own three-part setting of the famous Christmas carol Stille Nacht. I punched the score into the tape and tried different orientations of the punch tape. You can play it, so to speak, like dodecaphonic row manipulations: straight, reverse, inverted, and the reverse inversion, just by inserting the punch tape in different directions. The result of these operations sounded beautiful! And then Isabel suggested – this is something I owe to her! – ‘Can you imagine that I play that on the toy piano?’ So I made some sort of a transcription of the punch tape. She played it on the toy piano, and we also made a very nice video which you may know.

Artacho: Yeah, I think I've seen it! So the idea comes first, like in the case of the music box. In the first rehearsal when you meet with Isabel, is there already a full-fledged score? I also read from you this distinction between ‘Notat’ and ‘Notation’, which is also interesting. Is it already a finished text?

Essl:       It was always a finished text. Our first recording session for Kalimba was just for generating material that I needed for composing the electronic soundtrack. Afterwards, I gave Isabel the finished score and also the playback. During the rehearsal, of course, some things had to be adjusted or changed.

Artacho: Would you say that all the information required for the performance is in the score in a way that another performer could play it?

Essl:       That was always clear for me because there is a growing community of toy pianists worldwide. I think it started after 2005 after the Extensible Toy Piano Project at Clark University when a lot of musicians became acquainted with the instrument and wanted to play it. So I came in contact with this scene, and I was also collaborating with other musicians. Unfortunately, I could not meet all of them in person. Phyllis Chen I met once in New York. I wrote Whatever Shall Be for her. She commissioned me to write this piece, and we worked together in New York a few days before the first performance. Then she played the piece completely on her own. Then others did it as well, and also Isabel, of course.

Artacho: Clearly, these pieces are very successful; they’ve been played a lot, there's this community that plays them, Isabel has played hundreds of times. And there's a topic we also come to which is, how to evaluate a piece? In a concert, there’s the feedback of the applause. And there's of course the feedback of the performer, whether he or she's happy to play it. It is somehow a very difficult thing to grasp, like how do you deem a piece successful? Do you have a heuristic?

Essl:       Yeah, my heuristic is not the amount of applause, but the interest that it creates. For my toy piano pieces, I get a lot of responses and requests from outside. Many people want to play them, ask me about the score, the software, and the playback sound. For me, the indicator of success maybe are the number of performances, not only by one person, but by different performers in different parts of the world.

Artacho: Definitely, that must mean that performers like it.

Essl:       I must say that the performances are quite different. There are some people who can play very, very nice and wonderfully, and bring in their own personality and play differently. But I must say Isabel is still my favorite interpreter for my music. And she really has played ‘all’ of my pieces.

Artacho: That gives her a particular perspective over the pieces.

Essl:       The largest piece that I wrote was this ensemble piece for Ensemble Die Reihe. This was a sort of micro-concerto for toy piano and micro-orchestra. I received a commission to write an ensemble piece for Die Reihe, and I said: ‘Okay, I would like to write a toy piano concerto’. So I introduced the toy piano, so to speak, as well as Isabel into this context.

Artacho: It’s very interesting to me that you have another facet where you perform your own music. It is probably different from the pieces you write for specific instruments like the toy piano, but you also have these other pieces where you perform the live electronics yourself. Does it change the way you go about it? Do you focus less on a finished music text in that case? Or do you revise it more often?

Essl:       This is very different. There's a big bandwidth between fully notated scores and scores with live electronics, where the live electronics include random operations. This guarantees that each performance will sound differently. And this is also very interesting for the performers because when they can't rely completely on the electronics, like with a playback, they play differently, with more open ears, more awareness, and they are more involved. This is the concept of Sequitur and Whatever Shall Be. In general, each piece always has the same shape and you play the same notes, but the temporal development differs. There are some recordings of Whatever Shall Be for example, played by Isabel, by Phyllis Chen and others; if you compare their durations they are quite different. On the other side of the scale, there is this free improvisation stuff that I did for a very long time. The last few years it ceased a bit. I had this project with Agnes Heginger, Out Of The Bluea free improvisation duo for voice and electronics. Based on the concept that we only play on stage and never rehearse. We always played completely free without plans, although everybody's preparing him/herselfAgnes selecting lyrics and texts, whereas I might be selecting music material, respectively, creating computer programs. Then we come together on stage. We don't know what we’ll do. And we do music together. People often think that these are compositions, or songs, or something prepared, but it's not; it's always completely on the fly.

Artacho: So that's the main rule, it cannot be prepared.

Essl:       Absolutely! And this is an interesting concept of our collaboration, because nothing is written. There’s no master and slave, no composer and interpreter. We are acting on the same level and what happens comes out of the blue, this was the title of our first CD, and for us it is always a surprise what comes out. We never repeat the same piece, so it's always different.

Artacho: Yeah, that reminds me of the aesthetics of free jazz.

Essl:       Yeah, but aesthetically it's different. Agnes Heginger has a jazz and also a very strong classical background. But she also experiments with her voice and she knows lots of extended singing techniques. She's extremely good at hearing, listening and reacting. So she can immediately mimic what I'm doing on my computer with the electronics, and I can mimic what she's doing. So we are sending out our musical ping pong balls back and forth... and sometimes it's like a duel, some sort of Asian martial art. We're not hurting each other, but we are very quick and reactive and try to throw the other down, help him up in order to develop something together.

Artacho: Great. So there's no preparation, there's no score, there's no rehearsal. You could say that, in a way, the performances are the rehearsal. 

Essl:       The performance is the piece, it is the composition, so to speak. And I'm sort of proud of it, because we have done maybe 50 different pieces together, and each one can also be regarded as a composition. It's not just improvisation where you noodle around some material; there’s always some sort of formal development. And the dramaturgy, which we don’t know before, builds up, changes and reflects what has already happened before. It is like building a composition, where you're not only composing in a single direction, but also trying to remember what happened and develop this memory.

Artacho: Would you say that, over these 50 pieces you made together, a kind of a shared practice develops, where you begin to predict how the other one will react?

Essl:       Yes. I think in this case, there is an interesting development because in the beginning it really started out of the blue. And then we thought, ‘This was nice, we should do that again, but maybe differently’. Agnes Heginger always supplies the lyrics. She knows a lot of poems, and she also tries to find them in a way that they make up a good program together. She comes with lots of sheets that she has on her note stand, and she decides on the fly what to use. She may combine a line of Falco (the Austrian pop singer) with lyrics from Eichendorff, Ingeborg Bachmann, Ernst Jandl or Friedrich Achleitner. She's actually making a sort of real time collage of different texts. This has developed over the years in a very virtuosic way. What is interesting in this project is also playing with virtuosity, always trying to reach another peak of the mountain and not going the same way again.

Artacho: And everything live, which is even more difficult.

Essl:       But it's not a question of difficulty. It's just that we don’t want to repeat something that we have already done. There is, at least on my side, always the attempt to go further and further, arriving at different horizons. Unfortunately, our last concert Sommerwellen happened couple of years ago, and we haven't played since. Things have changed: currently I am more into writing scores again, so this improvisation part doesn't play a big role at the moment. But maybe it will change again, who knows?