Location determination of acoustical sources using a microphone array

In case of mobile loudspeaker arrangements to enable virtual acoustic applications there is an essential need to know precisely the placement of each loudspeaker in the real room. Within common state-of-the-art 3D audio rendering approaches the real positions of the loudspeakers are directly related to the computed loudspeaker feeds. Beside deviations of ideal arrangements, permissible product tolerances, etc. digital audio signal processing can be used to compensate for. The proposed basic approach, based on the usage of a microphone array consisting of four elements, describes a convenient solution to determine the real position of any loudspeaker within the rendering arrangement in azimuth, elevation and distance in relation to a defined reference point. Caused by a centrally located microphone array, the complex compensation gains can be easily obtained, too. Omitting a signal form a loudspeaker will cause different arrival times on the microphone array elements. Calculating time of arrival differences for each couple of elements will lead to a set of distinct delays. To solve the problem to directly assign the obtained set of delays to the corresponding position of the regarded loudspeaker in the three dimensional space, additional information based on the synchronisation between the loudspeaker arrangement and the microphone array is applied.