Development of open air sound barrier system using single microphone and speakers

Abstract

Music players usually build soundproof rooms in their houses. These rooms prevent noise problems among their neighbors when they practice at home. However, in soundproof rooms, vibrancy of musical sound is often lost, and music players feel as if the sound is cooped-up. Besides, installation cost of a soundproof room is usually high. We therefore aim to create a new sound barrier system. This system produces soundproof space in the open air by using single microphone and adequate number of speakers. The speakers cancel propagating waves which come from the musical instruments by outputting antiphase waves. The sound is muffled in the half sphere surrounding the player. Thus, the player can listen to their sound without losing vibrancy, while sound leakage outside the system is suppressed. Antiphase waves are predicted based on the wave equation with the signal picked up by the microphone as the boundary condition. In this presentation, a simulation for determination of the adequate number and position of the speakers is presented. Then, experimental validation is discussed in detail.