Acoustical Modeling in Architectural Acoustics

Abstract

It is imperative to investigate the acoustical properties of roms with the aid of models prior to construction. Two sound sources have been developed to facilitate these investigations. An air jet utilizing four intersection jets provides a nondirectional random noise, over a frequency range of 2400 cps to over 100 kcps for the study of the steady-state properties of rooms. A repeating spark generates an acoustical pulse having a rise time of less than 2 μsec and a duration of 20 μsec, providing a source for the study of the reflection of pulses within a room. These sources, with a 14-in.-diam microphone, are used in 1/50 scale models. Results utilizing these acoustical tools are illustrated by data on the absorption of direct sound over a sloping audience surface, reflection of sound from a canopy, side-wall reflections, and the acoustical performance of an orchestra enclosure.