A comparison of different surround sound recording and reproduction techniques based on the use of a 32 capsules microphone array, including the influence of panoramic video

摘要

This paper provides a comparison between the operational results obtained reproducing a three-dimensional sound field by means of traditional 1st order Ambisonics, and employing for the first time the virtual microphone technique 3DVMS. Audio and video were recorded at the same time, employing 32-capsules spherical microphone arrays and a panoramic video capture system of our design. In both cases, a matrix of FIR filters was employed, for deriving the standard 4 B-format components (Ambisonics), or 32 highly-directive virtual microphones pointing at the same directions of the 32 loudspeakers (3DVMS). A pool of test subjects was employed for comparative listening tests, evaluating some standard psycho-acoustical parameters. Furthermore, the same tests were repeated with and without the accompanying panoramic video. The tests were performed inside the 3Sixty room in the University of York, an immersive space with all-around video projection and a 32 speakers array. A complete set of IRs has been measured placing a microphone in the center of the room and sending a sine sweep test signal to each of the 32 loudspeakers. These IRs have been employed for equalizing individually each loudspeaker for Ambisonics and 3DVMS playback. In addition to this, we experimented with the capture of a live performance inside the room and with the virtual reconstruction of the complete audio-visual experience.