This paper presents an implementation of a near real-time timbre morphing signal processing system, designed to facilitate an element of ‘liveness’ and unpredictability in a musical installation. The timbre morpher is a hybrid analysis and synthesis technique based on Spectral Modeling Synthesis (an additive and subtractive modeling technique). The musical installation forms an interactive soundtrack in response to the series of Rosso Luana marble sculptures Shapes in the Clouds, I, II, III, IV & V by artist Peter Randall-Page, exhibited at the Peninsula Arts Gallery in Devon, UK, from 1 February to 29 March 2014. The timbre morphing system is used to transform live input captured at each sculpture with a discrete microphone array, by morphing towards noisy source signals that have been associated with each sculpture as part of a pre-determined musical structure. The resulting morphed audio is then fed-back to the gallery via a five-channel speaker array. Visitors are encouraged to walk freely through the installation and interact with the sound world, creating unique audio morphs based on their own movements, voices, and incidental sounds.