Method for improving sound projection performance based on linearly constrained minimum power algorithm

Sound projection is a technique that utilizes directional sound sources to project sound wave onto reflective surfaces, aiming to create auditory events in the direction of projected sound, which can be achieved via loudspeaker arrays beamforming. Being limited by the focusing capability of loudspeaker array, the direct sound that reaches the listener earlier than the projected sound can influence the localization perception of projected sound due to the precedence effect. Therefore, for sound projection, it is crucial to reduce the direct sound intensity relative to the projected sound. In this study, a beamforming method of weakening direct sound is proposed to improve the performance of sound projection. Based on the linearly constrained minimum power algorithm, where a beamforming null is set in the direction of direct sound, a beamformer for a 16-unit linear loudspeaker arrays is designed to reduce the level of direct sound. Then, the ratio of reflected sound to direct sound (R/D ratio) is used as a criterion to evaluate the performance of the proposed method by simulation. The results show that the proposed method has significantly higher R/D ratio compared to the traditional time delay method, which validates the effectiveness in reducing the level of direct sound.