Although Halffter’s electronic production has enjoyed some international prestige, it continues to be little known. The three compositions on this CD are interesting, not only because they represent an important period for the composer, but also because they are good creative examples of Halffter's use of electro-acoustics. One of the most characteristic elements of these compositions is the use of live electronics to broaden the instrumental possibilities and communicative potential. The 'Variaciones sobre la resonancia de un grito' relates to the tension accumulated through dictatorship and to the simultaneous cry of a multitude: the cry which circles the earth is an image which Halffter borrows from Chardin’s 'noosphere' (Pierre Teilhard de Chardin in 1922[4] in his Cosmogenesis: the noosphere/noösphere) is the sphere of human thought.

As Halffter himself asserts: “I believe the freedom we can achieve with electro-acoustic means is not only greater but also of a different nature, as long as it is we who dominate the means and not the means which dominates us”.