Flute Elena D’Alò
Electronics Giuseppe Silvi

The S.T.ONE project grew up from the need of an electroacoustic environment in which acoustical and electronic instruments have the same impact on listeners. The first stage of development involved a spherical sound diffusion technique of acousmatic music (exposed during EMUFest 2014) while a research path concerning the Sound Shape of traditional instruments was taking place. Sound Shape is the perceived shape of an acoustic object. During the recording of 13 Degrees of Darkness (Alvin Lucier, 2013, for flute and pre-recorded flute, italian premiere during EMUFest 2014) the TetraREC technique, for Sound Diffusion recording of acoustical instruments, was developed. Through acoustic S.T.ONE it is possible to read about state of the art research and to listen to instruments which are both recorded and analysed to describe their Sound Diffusion.

13 Degrees, Elena D'Alò Flute, TetraREC


TetraREC is a spaced microphone technique which consists in surrounding the complex sound object (musician plus instrument) with four microphones, each at the vertices of an ideal tetrahedron.

The TETRAREC technique took its inspiration from Michael Gerzon’s A-Format (four coincident microphones placed along the sides of a tetrahedron). The difference between the two techniques are the distance (coincident vs. spaced) and the purpose (3D reproduction of music/environment vs. 3D reproduction of acoustic objects).

The TETRAREC technique was developed to achieve the following objectives:

  1. Capture the Sound Shape of acoustic instruments
  2. Preserve the body shadow on sound propagation
  3. Preserve the movements performed by the musician
  4. Collect data on Sound Shapes of different acoustic instruments
  5. Collect data on Sound Shapes of similar acoustic instruments with different performers
  6. Analyse data and prototype a graphic visualisation of 3D Sound Shapes

Forthcoming Research

The largest corpus of contemporary music for solo instruments is represented by Luciano Berio’s Sequences. In this research about recording Sound Shapes through the TetraREC technique while diffusing them by S.T.ONE, where instrument performances are displayed over printed maps which are then used to improve their musical listening, a Sequenza could focus the listener’s attention on every nuance of the Sound Shape. At the same time reproducing a complex sound object like a musician performing a Sequenza (which very often implies a complex panoply of 3D movements) is the best possible research goal for a loudspeaker.

acoustic S.T.ONE - Track List

  • Density 21.5 - Edgar Varèse - flute Elena D’Alò
  • improvvisazione - Bayan - Alessandro Sbordoni
  • Sequenza IXb - Luciano Berio - Alto Sax Danilo Perticaro
  • Suite for toy piano - John Cage - Toy piano Francesco Ziello