MIMO auralization: An example of loudspeaker

Within the frame of SIPARIO, a project recently funded by the Italian region Emilia Romagna, it aims to virtually reconstruct both 3D audio and 360° video of real performances by recording and undertaking acoustic measurements inside the most historical theatres and concert halls spread all over the Europe. One of the most relevant topics of this project consists of the acoustic implementation of a new prototype of loudspeaker that will be necessary to properly determine the acoustic characteristics of these performing arts places. This loudspeaker can be employed in 3 different ways: one of the added values compared to a standard loudspeaker would be the simulation of a dynamic directivity pattern of any type of sound source that would be found in a performing arts place. This paper deals with the explanation of the other 2 types of techniques that the aforementioned prototype loudspeaker is able to perform. The loudspeaker can work like a traditional omnidirectional sound source by feeding the Exponential Sine Sweep (ESS) signal to all the 32 drivers in order to measure the room impulse response (RIR). Furthermore, it could have a complete spatial control of the sound propagation through the Multiple Input Multiple Output (MIMO) approach, owing to the spherical array of 32 channels for both source and receiver. In this paper the mathematical framework of previous articles has been applied to extract the arbitrary directivity of virtual microphones from real microphone array and for a virtual reality source from the spherical speaker array. Moreover, future developments of the new sound source are briefly described, including the applications for the specific project.