was composed at the Studio di Fonologia Musicale della RAI  in Milan. It was the first work in which Bruno Maderna made  extensive use of recorded instrumental sounds and their transformations—including ring modulation, reverberation and filtering—alongside synthetically generated sounds. It is also among  the earliest works to combine live performance on an acoustic  instrument with sounds played back from a fixed electroacoustic  medium.

The first performance of a preliminary version of the piece, without the opening section, took place on 11 June 1958 at the Conservatorio di Musica San Pietro a Majella in Naples, with Severino  Gazzelloni as flute soloist. The complete version was first performed only a few weeks later in Darmstadt, again with Gazzelloni.

Two editions of the work were published by Suvini Zerboni  (S.5573), in 1959 and 1960 respectively. Only the later edition is  currently available.

The original concept of the work grew out of an earlier project  exploring the possibility of combining acoustic and electronic  sound. Maderna initially planned an extensive serial composition which was to include other instruments as well; technological constraints and lack of time, however, eventually led him to  reshape the project as a work for flute, cymbal and magnetic tape.  The tape part was realised at the Institute of Phonetics of the University of Bonn, with technical assistance from Werner MeyerEppler, and the work was first performed on 21 July 1952 during  the International Summer Courses for New Music in Darmstadt. The 1958 version marks an important stage in the development of  Maderna’s compositional language, since the 1952 work had not  yet achieved a genuine integration of acoustic and electroacoustic sources. Musica su due dimensioni (1952) is in three sections:  the first is for tape alone, the second for solo flute, while the final  section again uses tape, together with a single stroke on the cymbal. The work is closed in form and contains no aleatory elements  of indeterminacy. The tape and flute material is entirely different  from that used in the 1958 version.

By contrast, Musica su due dimensioni (1958) offers a genuine  integration of flute and tape, while leaving performers considerable interpretative freedom. The music is notated without  bar-lines and offers various possible modes of realisation, allowing a relatively free interaction with the tape. The work can be substantially longer, up to approximately 11 minutes and 30 seconds vs ca. seven minutes in the 1952 version. The 1958 version  is divided into five sections. The tape may be described as a sequence of fragments separated  by pauses of varying length, pauses which are difficult to interpret  as musically measured articulations, silences, breaths, or fermatas. This suggests that the material was conceived as a substance  capable of being organised in different ways. 

The tape includes  both electronic sounds and recorded flute sounds subjected to  varying degrees of transformation. The electronic sounds are  morphologically highly diverse, ranging from impulses and gestures to pitched or noise-based textures, distributed across different registers, dynamic levels and spatial configurations.

The title Musica su due dimensioni explicitly invokes the idea of  a synthesis between two different sound sources. The boundaries  between them are not clearly defined. On the contrary, Maderna  organises the sound material in such a way that the listener is  not provided with an unambiguous perception of the differences  between instrumental, transformed and synthetic sound. What  the composer creates is a vivid, prismatic texture, from which  individual elements emerge in a constant oscillation between  foreground and background.

Source: https://ppeam.zhdk.ch/song/musica-su-due-dimensioni/