The Effect of Stage diffusers on the Stage Acoustics in a Concert Hall

The effect of diffusers on Early Stage Support (ST1) in a concert hall was investigated at 8 positions in a 1:25 stage scale model. Experiments were carried out when the stage floor was covered with and without absorption cloth to investigate the effect of stage floor reflection (absorption coefficient- 0.6 at 500Hz). To find out the effect of stage wall, three types of wall diffusers were used. As a result, absorption cloth on stage floor reduced the ST1 values at high frequency, but the average value of ST1 was not changed. Three types of stage wall diffusers were revealed as unaffecting, but it was observed that the ST1 values varied to positions of stage. The ST1 values were evenly distributed when hemisphere diffusers were used. Therefore, the use of floor absorption did not have much effect on the ST1 values, and the diffusers had some effect on the distribution of the ST1 values.