Adaptive Parameters in Mixed Music

Introduction

During the last several years, the interplay between processed and acoustic sounds has been the focus of research at the department of music technology at NTNU. So far, the project “Cross-adaptive processing as musical intervention” has been mainly concerned with improvised music such as shown with the music of T-EMP. However, through discussions with Øyvind Brandtsegg and several others at NTNU, I have come to find several aspects of their work interesting in the world of written composition, especially mixed music. Frengel (2010) defines this as a form of electroacoustic music which combines a live and/or acoustic performer with electronics. During the last few years I have especially come to be interested in Philippe Manoury’s conception of mixed music which he calls real-time music ( la musique du temps réel ). This puts emphasis on the idea of real-time versus deferred time which we will come back to later in this article.

The aspect of the cross-adaptive synthesis project which makes the most resonance with mixed music is the idea of adaptive parameters in its most basic form. A parameter X of a sound, influences parameter Y of another sound. To this author, this idea can be directly correlated to Philippe Manoury’s conception of partitions virtuelles which could be translated into English as virtual partition or sheet music. In this article, we will explore some of the links between these concepts, and especially how they can start to influence our compositional practices in mixed music. A few examples of how a few composers have used adaptive parameters will also be given. It is also important to point out that the composers named in this article are far from being the only ones using adaptive parameters, they have done it in either an outstanding and/or very pedagogical way when it comes to the technical aspect of adaptive parameters.

Partitions virtuelles, R elative Values & Absolute Values

Let us first establish the term virtual partition. Manoury’s (1997) conception comes originally from discussions with the late Pierre Boulez, although it was Manoury that expanded on the concept and extended it through Compositions such as “En écho” (1993-1994), “Neptune” (1991), and “Jupiter” (1987).

Virtual partition is a concept that refers directly to the idea of notation as it is used with traditional acoustic music. If we think of Beethoven’s piano sonatas, the notation tells us which notes to play (ie. C4 followed by E4, etc). It might also contain some tempo marks, dynamic markings and phrasing. Do these parameters form the complete list of parameters that a musician can play? The simple answer is no. These are only basic, and often parameters of relative value. A fortissimo symbol does not mean “play at 90 dB”, the symbol is relative compared to what has come before and what will come after. The absolute parameter that we have in this case, is the notes that are written in the sheet music. An A4 will remain an A4. This duality of seeing absolute against relative is also what has given us the world of interpretation. Paul Lewis will not play the same piece in the exact same way as András Schiff even though they will be playing the exact same notes. This is a vital part of the richness of the classical repertoire: its interpretation.

As Manoury points out, in early electroacoustic music this possibility of interpretation was not possible. The so-called “tyranny of tape” made it rather difficult to have more relative values, and in fact also limited the relative values of the live musicians as their tempo and dynamics had to take into consideration a medium that could not be changed then and there. This aspect of the integration of the electronics is a large field into itself which interests this author very much. Although an exhaustive discussion of this is far beyond the scope of this article, it should be noted that adaptive parameters can be used with most of these integration techniques. However, at this point this author does believe that score following and its real-time relative techniques permit this level of interactivity on a higher plane than say the scene system such as in the piece “Lichtbogen” (1986-1987) by Kaija Saariaho where the electronics are set at specific levels until the next scene starts.

Therefore, the main idea of the virtual partition is to bring interpretation into the use of electronics within mixed music. The first aspect to be able to do so is to work with both relative and absolute variables. How does this relate to adaptive parameters? By using electronics that have several relative values that are influenced either by the electronics themselves, the musician(s) or a combination of both, it becomes possible to bring interpretation to the world of electronics. In other words, the use of adaptive parameters within mixed music can bring more interpretation and fluidity into the genre.

Time & Musical Time

The traditional complaint and/or reason for not implementing adaptive parameters/virtual partitions in mixed music has been its difficulty. The Cross-adaptive synthesis project has proven that complex and beautiful results can be made with adaptive parameters. The flexibility of the electronics can only make the rapport between the musicians and computer a more positive one. Another reason that has often been cited is if the relationships would be clear to the listener. This author feels that this criticism is slightly oblique. The use of adaptive parameters may not always be heard by the audience, but it does influence how much the performer(s) feel connected to the electronics. It is also the basis of being able to create an electronic interpretation. Composers like Philippe Manoury for example, believe that the use of a real-time system with adaptive parameters is the only way to preserve the expressivity while working between electronic and acoustic instruments (Ramstrum, 2006).

Another problem that has often come up when it comes to written music, is how to combine the precise activity of contemporary writing with a computer? Back in the 80’s composers like Philippe Manoury often had to use the help of programmers such as Miller Puckette to come up with novel ideas (which in their case would later lead to the development of MaxMSP and Pure Data). However, the arrival of more stable score followers and recognizers (a distinction brought to the light in Manoury, 1997, p.75-78) has made it possible to think of electronics within musical time (ex. quarter note) instead of absolute time (ex. milliseconds). This also allows a composer to further integrate the interpretation of the electronics directly into the language of the score. One could understand this as the computer being able to translate information from a musical language to a binary language.

To give a simple example, we can assume that the electronic process we are controlling is a playback file on a computer. In the score of our imaginary piece, in 5 measures the solo musician must go from fortissimo to pianissimo and eventually fading out niente (meaning gradually fading to silence). As this is happening, the composer would like the pitch of the playback file to rise, as the amplitude of the musician goes down. In absolute time, one would have to program the number of milliseconds each measure should take and hope that the musician and computer would be in sync. However, by using relative time it is easier, as one can tell the computer that the musician will be playing 5 measures. If we combine this with adaptive parameters, we can directly (or indirectly, if preferred) connect the amplitude of the musician to the pitch of the playback for those 5 measures. This idea, which seemed to be most probably a dream for composers in the 80’s has now become reality  because of programs like Antescofo (described in Cont, 2008) as well as the concept of adaptive parameters which is becoming more commonplace.

The use of microphones and/or other sensors allows us to extract more information from the musician(s) and one can connect these to specific parameters however directly or indirectly one wishes. Øyvind Brandtsegg’s software also allows the extraction of many features of sound(s) and map these to audio processing parameters. In combination with a score follower or other integration methods, this can be an incredibly powerful tool to organize a composition.

Examples from the mixed music repertoire should also be named to give inspiration but also show that it is in fact possible, and already in use. Philippe Manoury has for example used parameters of the live musician(s) to calculate synthesis in many pieces ranging from “Pluton” (1988) to his string quartet “Tensio” (2010). In both pieces, several parameters (such as pitch) are used to create Markov chains and to control synthesis parameters.

Let us look a bit deeper into Manoury’s masterpiece “Jupiter” (1987). Although this piece is an early example of the advanced use of electronics with a computer, the use of adaptive parameters was used actively. For a detailed analysis and explanation of the composition, refer to May (2006). In sections VI and XII the flutist’s playing influences the change of timbre over time. The attack of the flutist’s notes (called note-incipits in May, 2006) control the frequency of the 28 oscillators of the chapo synthesizer – a type of additive synthesis with spectral envelope (Ibid, p. 149) – and its filters. The score also shows these changes in timbre (and pitch) throughout the score (Manoury, 2008, p.32). This is around the 23:06 mark in the recording done my Elizabeth McNutt (2001).

Several other sections’ temporality is also influenced by the performer. For example, in section II, the computer will record short instances of the performer which only be used later in section V and IX in which these excerpts are interpolated and then morphed into tam-tam hits or piano. As May (2006) notes, the flutist’s line directly affects the shape, speed and direction of the interpolations marking a clear relationship between both parts. The sections in which the performer is recorded is clearly marked in the score. In several of the interpolation sections, the electronics take the lead and the performer is told to wait for certain musical elements. The score is also clear about how the interpolations are played and how they are directly related to the performer’s actions.

The composer Hans Tutschku has also used this idea in his series “Still Air” which currently features three compositions (2013, 2014, 2014). In all the pieces, the musicians are to play along to an iPad which might be easier than installing MaxMSP, a soundcard and external microphone for many musicians. The iPad’s built in microphone is used to measure the musicians’ amplitude which varies the amplitude and pitch of the playback files. The exact relationship between the musician and electronics vary throughout the composition. This means that the way the amplitude of the signal modifies the pitch and loudness of the playback part will vary depending on the current event number which are shown in the score (Tutschku, personal communication, October 10, 2017). This use of adaptive parameters is simple and still permits the composer to have a large influence between performer and computer.

A third and final example is “Mahler in Transgress” (2002-2003) by Flo Menezes, especially its restoration done in 2007 by Andre Perrotta which uses Kyma (Perrotta, personal communication, October 6, 2017). Parameters from both pianists are used to control several aspects of the electronics. For example, the sound of one piano could filter the other, or one’s amplitude could affect the spectral profile of the other. Throughout the duration of the composition, the electronics are mainly processing both pianos, as they influence their timbre between each other. This creates a clear relationship between what both performers are playing and the electronics that the audience can hear.

These are only three examples that this author believes shows many different possibilities for the use of adaptive parameters in through-composed music. It is by no means meant to be an exhaustive list, but only as a start to have a common language and understanding on adaptive parameters in mixed music.

A Composition Must Be Like the World or… ?

Gustav Mahler’s (perhaps apocryphal) citation “A symphony must be like the world. It must contain everything” is often popular with composition students. However, this author’s understanding of composition especially in the field of mixed music has led him to believe that a composition should be a world on its own. Its rules should be guided by the poetical meaning of the composition. The rules and ideas that will suit one composition’s electronics and structures, will not necessarily suit another composition. Each composition (its whole of the score and the computer program/electronics) forms its own world.

With this article, this author does not wish to delve into a debate over aesthetics. However, these concepts and possibilities tend to go towards music done in real-time. For years, it was thought that the possibilities of live electronics were limited, but in recent years this has not been the case. The field is still ripe with the possibilities of experimentation within the world of through-composed music.

At this point in time, this author is also experimenting directly with the concept of cross-adaptive synthesis written into through-composed music. I see no reasons as to why it shouldn’t be used both in and out of freely improvised music. We should think of technology and its concepts not within aesthetic boundaries, but as how we can use it for our own purposes.

Bibliography

Cont, A. (2008). “ANTESCOFO: Anticipatory synchronization and control of interactive parameters in computer music.” in Proceedings of international computer music conference (ICMC). Belfast, August 2008.

Frengel, M. (2010). A Multidimensional Approach to Relationships between Live and Non-live Sound Sources in Mixed Works. Organised Sound , 15 (2), 96–106. https://doi.org/10.1017/S1355771810000087

Manoury, P. (1997). Les partitions virtuelles in « La note et le son: Écits et entretiens 1981-1998 » . Paris, France: L’Harmattan.

Manoury, P. (1998). Jupiter (score, originally 1987, revised in 1992, 2008). Italy: Universal Music MGB Publishing.

Mcnutt, Elizabeth (2001). Pipewrench: flute & computer (Music recording). Emf Media.

May, Andre (2006). Philippe Manoury’s Jupiter. In Simoni, Mary (Ed.), in Analytical methods of electroacoustic music (pp. 145-186). New York, USA : Routledge Press.

Ramstrum, Momilani (2006). Philippe Manoury’s opera K…. In Simoni, Mary (Ed.), in Analytical methods of electroacoustic music (pp. 239-274). New York, USA : Routledge Press.