Parametric Optimization of Acoustic Shell Geometry for Amphitheaters

A form-find model based on evolutionary algorithms

Abstract

The acoustic efficiency of shells in amphitheaters depends directly on geometry, which influences sound distribution in space. This article presents a simplified form-finding model for generating geometrically optimized acoustic shells using parametric modeling in Grasshopper and the Galapagos evolutionary optimization tool. The methodology defines geometric parameters and evaluates a single-criterion fitness based on early sound reflections. The optimization aims to maximize the homogeneous distribution of acoustic energy in the audience area by varying reflective surfaces for greater efficiency. Two audience configurations were tested: linear and radial. The results indicate how much more acoustically efficient the radial configuration is. The model enables comparison of dimensions and impacts on the acoustic shell, highlighting how simplified computational approaches can support open-air design in early project stages.