Do it Yourself (DiY) is a participatory culture which exemplifies a particular ethos in its approach to technology and materials. Rather than engage with ‘complete’ technologies, such as a technology supplied as ready-to-go item, the DiY practitioners examined in this thesis engage with the raw materials of garbage and recycling, ‘incomplete’, broken and discarded technologies. In this type of DiY practice the emphasis is towards creating individualised and custom-built forms of technology: often made from components and materials which have been re-functioned from their original intention to produce new and unexpected functionalities; practices which disrupt the dominant discourses of technology. This thesis involves a situated application of theory to DiY practices in the field: focusing on three case studies featuring New Zealand-based DiY sound practitioners and their embracing of functional ‘errors’ as a means of increasing the participatory potential of materials. My initial argument is, that the social perspectives and ‘human-biased’ view examined in current literature on DiY culture, depicts an attitude towards power and knowledge which obscures the recognition of material agency. In this thesis, ‘power’ is defined within a social constructivist, or as a ‘human-biased’ view, whereas ‘agency’, as the ability to make something happen, is more expansive and incorporates the capacities of materials to become active participants in the production of cultural artefacts. Through engaging with the work of contemporary theorists relevant to material agency (including Karen Barad, Jane Bennett, Levi R. Bryant, Susan Kelly, Lambros Malafouris and Bruno Latour), the limitations of the ‘human-biased’ view of DiY culture are highlighted and the emphasis is shifted from DiY participatory culture as a social phenomenon towards the idea of ‘extended agency’: agency which includes both human and material actants within the entangled assemblages of DiY practices and the material environment. When extended agency is applied in the three case studies, the initial question asked is: ‘How does the intra-action of human and material environment influence the processes of DiY practices and what specific strategies are used to increase the participatory potential of materials?’. In this sense, DiY culture challenges the way we see ‘power’ and ‘structure’ as being exclusively human traits, influencing our way of relating to the material environment and creating consequences and considerations which extend from the localised DiY practices examined in this thesis. The suggestion is that the extended agency of DiY culture represents a timely re-evaluation of the relationship between the human and the material environment, challenging prevalent discourses which place the human at the centre of power and knowledge.