Mantra for two pianos and live electronics is an example of application of a new compositional method, called by Stockhausen ���Formel Komposition���. The piece includes a particular instrumentation (cymbales antiques and wood blocks) and a live sound processing of piano sounds. It is, according to the composer, related to the creation of a new idea of ���symbiotic��� and ���utopian��� composition. It is also a very structured composition based on the rules of a new compositional method. The different aesthetic interpretations of the piece in the context of theoretical studies suggest different outcome in the performances. These can be related to the aesthetic points of view studied in the musicological field. My analysis starts from this assumption and examines some recorded fragments of different performances compared by listening and by signal analysis.