Sound diffusion – the realtime (usually manual) control of the relative levels and spatial deployment during performance – is one of the most contentious issues in the field of electroacoustic music. There are parts of the world where the practice is virtually unknown; in other places it is the norm and appropriate facilities would be provided as a matter of course for any visiting composer or performer. These ‘local variations’ are not merely ripples on the surface of a standardised performance practice but stem from underlying attitudes to what composition and performance in this medium are about and, ultimately, to a definition of music itself. What follows summarises observations drawn from fifteen years of working with the BEAST concert diffusion system in numerous performance spaces in the UK and Europe, as well as experiencing, both as listener and performer, other systems in Europe and North America. Scientific rigour, in the normally accepted sense of tables of measurements etc., is not my goal – my portable measuring equipment has been my ears, and my conclusions are based on what I have heard.