Two texts on electroacoustic music (PDF) available online

Two texts on electroacoustic music, written by Dariusz Mazurowski are available online now. The first one, about the history of sound processing and editing is in Polish:
The second one (Space, diffusion, perception. Selected techniques and processes concerning spatial sound in acousmatic and mixed music) is in English:
Supported by the Ministry of Culture and National Heritage of Poland as a part of “Culture on the web” program.