Situated and non-situated spatial composition (IEM #7)

What do I think I mean by space in spatial composition? In this post I want to outline a distinction between situated and non-situated spatial composition, at least as it applies to my use of the IEM icosahedral loudspeaker (ICO) and 24-channel hemisphere array. This distinction extends upon an earlier post arguing for the ICO as an instrument for electronic chamber music.

In multichannel composition, including ambisonic works (and the very few wavefield synthesis compositions that exist), space is generally understood as the acoustic space, as a virtual sound field (VSF) and its shaping over time, created within the listening space, whether this be via headphones or a loudspeaker array of some sort in a room. The VSF is a composed space, which may consist of multiple other kinds of spaces (outlined in considerable detail by Denis Smalley PDF) either real or virtual in provenance but which ultimately are all virtual spaces, regardless of this provenance. A microphone recording of a real-world scene (a field recording) is a real space rendered virtual through the decontextualisation of recording and recontextualisation within the VSF of the musical work. In some cases the spatial resolution of the recording and its reproduction (recontextualisation) may be very high indeed, such that it might pass a blind listening test (an odd idea, but it has a history). In other instances the recording might be of a lower resolution such that the listener can identify the scene captured in (not by) the recording but would acknowledge that a spatial transformation has been enacted (stereo recordings “flatten” real acoustic space even as they convey a strong sense of space). Where the VSF is created through entirely synthetic means, say additive synthesis with multiple delay lines creating a sense of the sound coming into being within a space (implying reflections and reverb), the VSF is not real but has qualities which are heard as spatial through reference to real world acoustic spaces. Between the fully virtual space heard as having real world (i.e. physical) qualities and the real world space that is rendered virtual through recording, there are hybrid spaces created by digital audio processing which may transform the spatiality of recordings or impart new spatial qualities upon any sonic materials (the VSF created by impulse response reverberation is paradigmatic here). Such digital events and interactions are of course virtual, even if they convey qualities that impart a sense of the real world. [Another way to say all this, but quickly: the spatial attributes of sound within the VSF are a product of reference to the physical-acoustic spatiality of the real world, regardless of the actual provenance of the VSF.]

Spatial composition is engaged with the VSF alone unless it engages directly with the sonic space that contains the VSF – the room – and with the interactions between the VSF and the space of its reproduction or audition (the real physical space in which sound is reproduced and heard) in a way that transforms the VSF itself. The room itself usually is not taken into consideration, or even considered, unless it in some way interferes with the the VSF. (One could think of the room in Heideggerian sense: it is a tool for presenting music and isn’t noticed until it itself speaks, which in this case means, speaks out of turn, interferes) Typically, such interference is something to be counteracted so as to ensure that the VSF is compromised to the least possible extent. A composer or sound artist working within this understanding is engaging in non-situated spatial composition. The musical work here is self-contained and can be transposed from from one space to another without transformation. However, if the real space is brought into deliberate interaction with the VSF, or at an extreme is entirely integrated with it, then we are talking about situated composition. The situated composition, like site-specific art, cannot be moved from the site for which it has been realised, without transformation.

There’s a great deal to be said about this topic, and many examples that could be discussed, but here I’m focusing on the way that the ICO requires an approach that is situated (unless one uses it simply as another – albeit prolific – loudspeaker, which is entirely to ignore its full potential, something I discussed in an earlier post). The ICO affords and encourages a situated approach because one of its most interesting uses is as an instrument to “orchestrate reflecting surfaces” (Sharma and Zotter, PDF) and to do this of course requires that the VSF itself is brought into close relationship with the room acoustic. This means that the way in which one spatialises music material with the ICO will have to be created anew, or at least adapted, if this material is shifted from one room to another, especially if the material itself has been created to allow space to be given emphasis in the composition (which seems to require a reduction in the complexity of the music itself). Furthermore, given that each room has its own acoustic qualities, it is the case that not all materials will afford equal spatiality in all spaces (an upcoming post will explore this topic). At an extreme, this means that a situated work might truly be site-specific – to move the piece is to lose the piece (so to say). The IEM hemisphere on the other hand, is simply yet another multichannel array. A carefully considered and constructed array, but more or less homogeneous with other arrays which have been designed to allow the realisation of non-situated VSFs (just like cinemas, which can be better or worse, but in the end are designed for cinematic experience, not the experience of a cinema).

Working with the ICO and the hemisphere together for Let x = required that I minimise the situated-composition potential of the ICO, constraining such usage to spatial effects (there must be a better word to use than this…) which either strongly contrasted with the VSF of the hemisphere, or which afforded smooth blending between the two. In the former I tended to use the ICO solo, used as a complex acoustic surface, with layered textural materials skittering and moving across its surface, emphasising direct sound (the half of the ICO oriented towards the audience) more than indirect. In the former I tended to use the ICO to create reflections in the front-left corner of the room (directly behind the ICO), which allowed blended transitions between ICO “solos” and sections in which the hemisphere predominated (this worked because it was difficult to distinguish between reflected sound from the ICO and direct sound from the hemisphere in this part of the room). Such usage was not necessary and certainly there are many other possible approaches to combining the ICO and the hemisphere, but this approach was taken partly as a response to the site-specific limitations of using the ICO in IEM’s smallish (for a concert hall) Cube space. The size of this space means that the audience sits quite close to the ICO, reducing the possibilities for orchestrating reflections (for most of the audience there’s too little difference between direct and reflected sound for this to be compositionally useful, excepting the cases just described). In other words: in using the ICO I took an approach that was situated, perhaps even site-specific, but which didn’t fully explore the ICO’s potential as an instrument. So when Let x = is presented in another space it will required fair amount of reworking (I’m ignoring the conundrum of what to do with music written for an instrument – the ICO – that only exists at IEM). In using the hemisphere I took a standard compositional approach, the creation of a VSF which can be realised using any similar multichannel system, and this approach was only minimally adapted to afford a certain set of interactions with the ICO.

What would be interesting as a next step is to move this hybrid (non-)situated piece into a larger space, to hear to the ICO in interaction with such a space and listen to the ways it demands that my materials and spatialisation be transformed in order to remain effective. If this isn’t possible, then I’ll know that Let x = is a fully situated work.





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