versão portuguesa english version

The Project AUDIENCE

Sounding with AUDIENCE

Scientific and Technological Production

Call for Works, Contributions and Opportunities

Team, Colaboration, Support, Partners, Associated Projects and Groups





Known since the 70’s when first coder/decoder proposals showed up, the Ambisonics sound coding system is based in an elegant mathematical formulation where both spatial and temporal sound information is coded into 4 vectors – x, y, z, and w (for 1st. order Ambisonics), as if it were projected onto cartesian axes.

Initially conceived to register a real sound field recorded by soundfield microphones, this format can be adequately adapted to permit the computer simulation and creation of artificial sound fields. To reproduce the sound, the vectors are accordingly transformed in outputs for loudspeakers distributed in a known configuration around the audition area. A clear advantage of this method is in its flexibility to choose the number of loudspeakers one wants to use, and their positions around the audition area.

Ambisonics scheme (both sound objects and loudspeakers
have their location in the space parameterized by the system)

Wave Field Synthesis

The second format (Wave Field Synthesis – WFS) is more recent, and is based on a more computational complex formulation involving the physical modeling of the sound waves propagation in the environment, and takes into consideration a discretization of the physical space of the audition area.

In this technique the main goal is to emulate a wave front that would be produced by real sound objects in a specific acoustic environment, through the usage of a densely distributed loudspeaker array around the audition area. An advantage of this technique is its higher tolerance to more listeners inside the audition area and its capability to induce the perception of sound fields located on a larger audition area, including the possibility of positioning objects in the middle of the area, around or among the listeners, and formed ahead of the loudspeakers.

The wave front synthesis is a critical task, and may implicate in a high computational cost, which we intend to approach using cluster computing, distributing the computational tasks and calculus associated to the auralization process over the nodes of a computer cluster.

Wave Field Synthesis. (left) sound source behind the wall. (right) sound source inside the listening area.



  Laboratório de Sistemas IntegráveisEscola Politécnica