We discuss John Locke's ideas in his essay of 1690 on sound and its cognition and relation to bodily motion. The ideas have interesting implications for the construction of organised sound. We argue that our ecological and statistical experience of sounds in our natural (and man-made) environment is in several respects critical for our choices as soundsmiths and our impressions as listeners. Sonic repetition, both sensory and imag(in)ed, contributes to that environment. Input sounds may be ‘coupled’ to output sounds; and in some cases the physical processes generating sound and the cognitive processes of receiving them are joined. As music technologists we may think of the computer, our sonic vehicle, as a joined bodily sonic-prosthesis. ‘Simple’ sonic ideas may associate with each other through shared biological bases, and become tools for creation of ‘complex’ ideas, as Locke cogitates. Furthermore, we now have new routes towards such complex sounds, including our computer prostheses.