A field-matching method for sound field synthesis for large scale sound reinforcement systems

There have been ongoing attempts to adapt existing Sound Field Synthesis methods for large scale sound reinforcement systems. In comparison to smaller indoor setups large scale systems have significant distances between secondary sources and often irregular loudspeaker layouts due to rigging conditions. These restrictions make the use of WFS-related methods unfeasible. In addition, prominent and frequency-dependent directivity patterns of concerts loudspeakers obstruct the use of usual level and delay algorithm as it assumes omnidirectional secondary sources. The paper proposes an alternative method based on a Field Matching technique that bypasses the above-mentioned restrictions. Despite the typically low aliasing frequency of a concert sound system layout the Field Matching approach was shown to provide an accurate localisation and a stable virtual source across the audience area including front seats. The paper presents a theoretical background and a Matlab simulation along with listening tests results. Limitation and challenges of the method for live sound applications are discussed.