The article deals with group classes where educated pianists from eight to ten years of age experiment with a “prepared piano” approach to contemporary music. The aim is to show how the search for a musical aesthetic unknown to students is the pretext for interpreting, and how the teacher devolved to the students is responsible for the act of interpretation, which we will define. We will see how the aesthetic experience of searching for a ‘sound’ is anchored or not bodily. The data collected consist mainly of video films. They are addressed from an anthropological perspective as part of a joint action theory in didactic with ethnographic methodology. The use of the concepts of contract, environment, educational balance and devolution is specified.