Conclusions

Solo, written in 1966 by Karlheinz Stockhausen, a pioneer of electroacoustic music, is an example of the evolution of the concept of `work' by means of technologies. From the beginning, in the conception of the composer himself, Solo is a piece in which we can find a character of open performance. In fact, in this work there is the possibility for the performer to organise the score in a personal way. The performer can choose inside the score the points and the passages to build his own composition. He can choose, from six different versions, his own performance version with specific characteristics. Also, one of the structural features of the piece is to be different even in each performance in the instrumental and in the electronic parts. These structural features are emphasized in the course of time by the technological evolution. In fact, the new technologies allow us to realise not only a personal interpretation of the score as in the original idea of the composer, but also a different conception of the work until we get an idea of open work and soundscape. This latter possibility has been tested recently in a waterside concert.