Wolfgang Thomas

Aspects of sound perception in absence of visual stimulae in relation to the ‘Brain Drain’ installation

1. General prerequisites of the installation

The basic principle of the installation is to use sound as an input into a performer’s brain, picking up his reactions by means of a portable EEG device – which translates brainwaves into four channels of emotional states – and then to output these states as projected visuals.

In order to obtain the least amount of brain data distortion – where the performer would be distracted by stimulae outside of sound – and so as to not feed back visual impressions into the brain, the person wearing the headset needs to be placed in a fairly dark room, and be blindfolded.
By nature, this alludes to the principles of acousmatics (Cp. Schaeffer 2004, p.76ff), and in turn to Chion’s “Listening Modes” (Chion 1994, p.25ff).

Aspects of both phenomena need to be investigated in the following, as do general observations relating to auditory perception and cognition, and their relevance to the installation.

2. Specifics of auditory perception and how they relate to the installation setup

In principle, our auditory sense allows us to perceive signals located at any point on or in a sphere, i.e. we are able to hear sound on three axes. Further it provides us with the ability to gauge sound source distance. Having said that, there are various limitations to each of these capabilities, especially when deprived of simultaneous additional visual information. (Cp. Raffaseder 2010, p.125/Farnell 2010, p.81)

Generally, our ears provide us with more precise information where the x-axis of spatial depth (left-right) is concerned, and less precise information where the y-(above-below) and z-(front-back) axes are concerned. (Cp. Raffaseder 2010, p.125) Head movement is employed to augment the process of spatial localisation. (ibid)

Judging distance fundamentally works by way of assessing loudness or sound volume, and to a lesser extent frequency content. However, absence of comparative values, based on our expectations of how loud a specific sound would be (Cp. Farnell 2010, p.80), can easily confuse our judgement regarding this. Consequently, not being able to gather any visual information on sound sources further distorts our assessment of sound source distance.

Of equal importance is the fact that we are able (and constantly using this ability) to gather a multitude of further informations about sound sources: We make assessments of their size, material, and even their cause and thus their situative context, deriving meaning from them in the process. (Cp. Raffaseder 2010, p.46 ff) In effect, a large part of our everyday listening practices consists of what Chion famously classified as “Causal Listening”. (Chion 1994, p.25ff)

Knowing about these phenomena of course provides us with the possibility to consciously influence the listener’s perception in an installative context such as the one we are working on.
Possible means of doing this, and routes we are exploring, concern such as creating various sounds that are in themselves limited to relatively narrow frequency spectra and pitch ranges – while between them covering a wider range of frequencies, pitches, and timbres – and experimenting with spatial placement as well as distance to the performer.

Further, employing surface loudspeakers provides us with the opportunity to change the reverberation characteristics of a given space, by means of adding material reverberations to those prevalent in the room where the installation takes place. A practical example would be the application of such speakers to metal sheets, which give an impression of a fairly large space, even when set up in a small room.

Another area we are exploring is that of acousmatics, which by definition is very much a core element of the installation by virtue of the performer being blindfolded, and thus only able to hear but not see. (Cp. Schaeffer 2004, p.77)

Furthering on the concept, we have so far deliberately tried to create sounds that are generally not readily classifiable as coming from an easily identifiable sound source, by means of either altering or changing the way sound objects are ‘played’, or by building pukka ‘instruments’.
Indeed, the augmentation of spatial and timbral characteristics as explained above might help in intensifying the acousmatic effect.

The idea is that, when exposed to it long enough, the listener might begin to concentrate purely on the sonic features of any given sound, in the process being less and less concerned with questions of cause and the implications and connotations thereof.

This alludes to what Chion calls “Reduced Listening” (Chion 1994, p.29), and we are hoping to derive from it insight on how sound characteristics, as opposed their source and meaning, affect the emotional state of the listener. An interesting sub-aspect of this will be to find out whether it is actually possible to deliberately cause a listener to enter a state of Reduced Listening.

However, this would not likely be discernible from his emotional response but would have to be investigated by means of having the performer verbally describe the listening experience.

3. Concluding remarks

The techniques I explained above will naturally have an effect on the performer’s sensual perception, simply by way of him/her being exposed to sensual input.

How they specifically affect his/her emotional state is what we are looking to find out about, and represent. Having said that, it needs to be taken into consideration that factors other than sound will affect the performer’s emotional state – even just being deprived of sight will have a considerable effect, more so when combined with auditory input, which is likely to create – at least initially – a feeling of unease, as no visual confirmation of sound sources is possible. (Cp. Connor in: Coyne 2010, p.55)

Still, we are trying to obtain as much information as possible about the performer’s emotional state when exposed to sound, which will on the one hand enrich the visual part of the installation, on the other hand will hopefully provide us with usable data and experience for future work.

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Reference list:

CHION, M. (1994) Audio-vision: sound on screen/Michel Chion; edited and translated by Claudia Gorbman; with a foreword by Walter Murch. Columbia University Press, New York.
COYNE, R. (2010) The tuning of place: sociable spaces and pervasive digital media, The MIT Press Cambridge, Massachusetts, London.
FARNELL, A. (2010) Designing Sound, The MIT Press Cambridge, Massachusetts, London.
RAFFASEDER, H. (2010) Audiodesign, Carl Hanser Verlag, München.
SCHAEFFER, P. (2004) Acousmatics. in Cox, C., Warner, D. (eds.), Audio culture – readings in modern music, Bloomsbury Academic, New York, London, pp 76-81.