Lateral low‐frequency components of reflected sound from a canopy complex comprising triangular plates in concert halls

Abstract

Applying the diffraction integral of Rubinowicz, the transfer functions (TFs) for reflection by canopy panels of various shapes were calculated. Numerical calculation of TF shows that the optimum interior angle of an isosceles triangle giving a flat response lies between 90° to 120°. And, the use of a number of canopy panels above both sides of a concert hall helps to control lateral low‐frequency components for the audience area, and produces a small value of interaural cross correlation (IACC). It is interesting to observe that the interior angle of the triangular panels composing the canopy in the Tanglewood Music Shed falls in the optimum range. The TFs of large triangular panels suspended in front of the top of the proscenium arch in Fujita Hall, a concert hall designed by us, indicate the existence of relatively strong low‐frequency components of reflection from lateral directions to a listener at the front section of the hall. Further, higher frequency components of the reflections tend to arrive near to the median plane of each listener.