Conference_programme: 18.9 - Archeo-Acoustics

Lecture: Acoustic Simulation of Julius Caesar's Speech at the Battle of Pharsalus

Author(s): Boren Braxton

Summary:
History contains many accounts of speeches given by civic and military leaders before large crowds, prior to the invention of electronic amplification. Previous research has shown that several thousand people could intelligibly hear an unamplified speaker, depending on the speaker’s oratorical ability and vocal level, as well as the level of crowd noise. Some accounts of such speeches are certainly plausible, such as a speech to a quorum of 6,000 members of the Athenian assembly. Others are almost certainly acoustically impossible, such as Aemilius Paulus’s reported speech to his army of 86,000 before the battle of Cannae during the Second Punic War. One borderline historical speech is that given by Julius Caesar to his army of approximately 22,000 men before the battle of Pharsalus during the Roman Civil War. Caesar’s background and education are discussed, including his training in rhetoric and oratory, which would have affected his articulation and effective sound pressure level while addressing his troops. Based on subjective reports about Caesar’s oratorical abilities, his effective SPL is assumed to be 80 dBA, about 6 dB above the average loud speaking voice but lower than that of trained actors and singers. Background noise, one of the most important considerations for intelligibility simulations, is assumed to be quite low due (around 45 dBA) due to the discipline of Caesar’s troops and the intense loyalty they held toward their commander, leading to a signal-to-noise ratio of 35 dB. It is shown that, depending on assumptions about environmental conditions and troop formation, Caesar could likely have been heard intelligibly by up to 20,000 troops, making the account of his speech acoustically plausible.

Corresponding author

Name: Prof Braxton Boren

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Country: United States