The composition and performance of spatial music
Enda Bates · Arrow@dit (Dublin Institute of Technology) · 2009
The use of space as a musical parameter is a complex issue which involves a number of different, yet interrelated factors.The technical means of performance, the sonic material, and the overall musical aesthetic must all work in tandem to produce a spatial impression in the listener which is in some way musically significant.Performances of spatial music typically involve a distributed audience and often take place in an acoustically reverberant space.This situation is quite different from the case of a single listener at home, or the composer in the studio.As a result, spatial strategies which are effective in this context may not be perceived correctly when transferred to a performance venue.This thesis examines these complex issues in terms of both the technical means of spatialization, and the compositional approach to the use of space as a musical parameter.Particular attention will be paid to the effectiveness of different spatialization techniques in a performance context, and what this implies for compositional strategies which use space as a musical parameter.Finally, a number of well known works of spatial music, and some original compositions by the author, are analyzed in terms of the perceptual effectiveness of the spatialization strategy.The results of a large number of listening tests and simulations were analysed to determine the fundamental capabilities of different spatialization techniques under the less than ideal conditions typically encountered during a performance.This analysis focussed on multichannel stereophony, Ambisonics, and Wavefield Synthesis.Other methods which are orientated toward a single listener are not addressed in this thesis.The results indicated that each spatialization scheme has particular strengths and weaknesses, and that the optimum technique in any situation is dependent on the particular spatial effect required.It was found that stereophonic techniques based on amplitude panning provided the most accurate localization but suffered from a lack of spaciousness and envelopment.Ambisonics provided an improved sense of envelopment but poor localization accuracy, particularly with first order Ambisonics systems.Consequently it would appear that stereophony is preferable when the directionality and focus of the virtual source is paramount, while Ambisonics is preferable if a more diffuse enveloping sound field is required.Ambisonics was consistently preferred for dynamically moving sources as this in existing ambisonic hardware such as the Soundfield microphone.The FMH set of coefficients for encoding a signal into third order Ambisonics is shown in Table 4.1. Criteria Furse Malham N3D N2D Hybrid W SN3DExtensible to higher orders in a straightforward manner.Hence able to meet expanding users needs.