Abstract: Three-dimensional Virtual Sound Barrier(VSB)system can generate a quiet zone of a human head size in a normal room with noise coming from many different directions.Since a practical VSB system has to be implemented surrounding a human's head,the effect of such a diffracting sphere on the performance of the system should be considered. Due to the diffraction of the human head,the noise reduction distribution around the human head tends to be uniform. It can improve or reduce the performance of the system depending on the size of the zone surrounded by the error sensors and the noise frequency.Numerical simulations show the same tendency of the control performance with respect to the configuration of the system with and without the head.The head can move in the quiet zone of the VSB system.The control performance decreases with the increase of the distance between the head and the centre of the system.However, the noise reduction level keeps more than 10 dB even when the head is near the edge of the quiet zone.Finally,a 16 channels practical cylindrical VSB system has been developed.Experimental results in a normal room show that when the head is investigated,the control performance increases under this situation and the minimal noise reduction level can be up to 13.3 dB in the frequency range of less than 500 Hz with the head moving in the quiet zone.