Free listening‐point synthesizing method in a large microphone array using acoustic transfer function

Abstract

In this research a free listening‐point synthesizing method is proposed by using the measured acoustic transfer function (ATF) in a large microphone array for future 3‐D audiovisual systems. ATFs at the location of far‐field microphones are estimated in frequency domain by using a recorded time‐stretched pulse (TSP) signal broadcasted by speakers at the location of sources. Then an ATF pool is generated with a chosen density by synthesizing the estimated ATFs for each sound source. The ATF pool contains all the microphones’ locations, plus synthesized ATFs with a chosen density from sound sources to any point on the arc which passes all of the microphones. The free listening‐point is generated by selecting the ATF for each source from the ATF pool. Then the source microphone sounds are convolved with the chosen ATFs and added. The proposed method is evaluated by an array with 38 microphones in the far field on an arc with r=4 m with 20 cm between each pair of microphones, and two microphones close to two sound sources with 1.5‐m distance. Experimental results have been shown for the estimated ATFs and comparison of the synthesized arbitrary listening point with the actually recorded sound for a given point that shows satisfactory results.