Just like acousticians, acousmaticians derive from Pythagoras. They were the philosopher’s disciples who could only listen to him, and only off-stage – they were separated from the teacher by a thick curtain. It is said that this made them move their attention from the medium to the heart of the matter. By analogy, to listen in an acousmatic way, you should forget about the measures and indulge in the ‘heart of music.’ The role of the heavy curtain is most commonly a speaker which allows the sounds to stay more or less incognito. When there are sixty or more speakers, you can be pretty sure it is the Acousmonium – created by François Bayle in 1972 speaker orchestra. The instruments making up the orchestra vary in size and reach, and are placed at different points in the concert hall.