ABSTRACT The author describes various aural techniques developed as part of the origination of the sonic content of compositions themed on palimpsests of time and place. Field-based recordings, authentic and synthetic impulse responses, convolution reverb and the use of third-party sounds retrieved via open programmatic interfaces are considered. The role of usability feedback is also discussed, specifically its beneficial impact on informing the development both of the compositions and the techniques they utilize. An initial mobile phone application is described, together with continuing work to develop additional mobile experiences.