Outdoor oratory and performance space

Spoken sermons and oratory in the West have usually been confined to the interior of churches or parliaments that bear similarities to traditional concert halls. However, the largest crowds in history are described as being outside due to the size constraints of most interior spaces. Historical estimates of crowd sizes or the intelligible range of speakers have generally been quite speculative. However, recent work has used an acoustical experiment by Benjamin Franklin to estimate the 1 m on-axis average SPL of the Anglican preacher George Whitefield at 90 dBA. Computational simulation of Whitefield’s preaching in London confirms Franklin’s estimate that he could have been heard by crowds of 30,000 or more depending on weather conditions and crowd noise. Using Whitefield as a benchmark, other historical orations may be evaluated based on geometric and acoustic factors. Within this framework, speeches given by Pericles, Demosthenes, Alexander the Great, and Julius Caesar are examined based on the size and noise of the crowd as well as the level attainable by each speaker. In each case, outdoor oratory possesses unique performance considerations distinct from interior or musical settings.