This thesis documents research in the field of sound diffusion for the live performance of electroacoustic music. Broad and inclusive ways of conceptual ising electroacoustic music are presented, with the intention of promoting the design of improved sound diffusion systems in the future. Having defined 'electroacoustic music' in terms of the technologies involved and the unique ways in which these creative frameworks are appropriated by practitioners (Chapter 1), a binary interpretation of the electroacoustic idiom, whereby musical philosophies can be regarded as either top-down or bottom-up, is given (Chapter 2). Discussion of the process of sound diffusion itself reveals two distinct performance praxes, which can also be characterised as top-down and bottom-up (Chapter 3). These differing ideologies, in addition to the technical demands of the electroacoustic idiom and the logistical demands of sound diffusion itself, must be accommodated by the sound diffusion system if live performances are to achieve the desired musical communication. It is argued that this is not presently the case. A system of criteria for the evaluation of sound diffusion systems is presented (Chapter 4). Two original concepts - the coherent audio source set (CASS) and coherent loudspeaker set (CLS) - are also presented; these are intended to be practically and theoretically useful in the field of sound diffusion. Several existing diffusion systems are evaluated in terms of these criteria (also Chapter 4). A description and evaluation of the M2 Sound Diffusion System, which was co-developed by the author as part of this research, is also given (Chapter 5). The final chapter describes ways in which superior future systems can be devised. These range from specific practical suggestions to general methodological recommendations. Overall, the intention is to provide an interpretation of the electroacoustic idiom that can be used as a heuristic tool 111 the design of new sound diffusion systems.