This article presents Autocousmatic, an algorithmic system that creates electroacoustic art music using machine-listening processes within the design cycle. After surveying previous projects in automated mixing and algorithmic composition, the design and implementation of the current system is outlined. An iterative, automatic effects processing system is coupled to machine-listening components, including the assessment of the "worthiness" of intermediate files to continue to a final mixing stage. Generation of the formal structure of output pieces utilizes models derived from a small corpus of exemplar electroacoustic music, and a dynamic time-warping similarity-measure technique drawn from music information retrieval is employed to decide between candidate final mixes. Evaluation of Autocousmatic has involved three main components: the entry of its output works into composition competitions, the public release of the software with an associated questionnaire and sound examples on SoundCloud, and direct feedback from three highly experienced electroacoustic composers. The article concludes with a discussion of the current status of the system, with regards to ideas from the computational creativity literature, among other sources, and suggestions for future work that may advance the compositional ability of the system beyond its current level and towards human-like expertise.