MIMO Technique applied to the Greek Theatre of Tyndari

Spatial Multiple Input Multiple Output (MIMO) is an innovative technique developed to provide an appropriate filter array required to virtually reconstruct the perceived sound field at the listener's position, generated by a sound source with arbitrary and time-varying directivity. This is particularly useful when the sound source has a complex directivity pattern (e.g. the human voice or specific musical instruments). To mimic the directivity of a real sound source, a “DodecMIMO” was developed. This prototype loudspeaker is capable of simulating the directivity of any dynamic sound source as well as a standard omnidirectional sound source. Prior to field applications, the sound source was measured in an anechoic chamber to obtain its acoustic characterization. The first on-site application took place in the Greek-Roman theatre of Tyndaris (Sicily, Italy). The measured impulse responses (IRs) were analyzed and compared with previous acoustic studies performed with omnidirectional sound sources. The outcomes were used to compute the acoustic maps for each measuring point by overlapping the panoramic image acquired at each position with the acoustic response recorded by the microphone. This innovative technique is very well suited to create a virtual 3D audio reproduction, technically called auralization, which can faithfully reproduce a complex real sound source.