During the 17th, 18th, and 19th centuries, a room acoustic theory arose with design goal to avoid echoes from occurring by quantifying the perception threshold between direct sound and 1st-order reflections. The room acoustic design of the large 19th century concert hall Palais du Trocadero (1878-1937) was based on this theory. As the resulting acoustics were notoriously poor, an attempt was undertaken in 1909 to correct the acoustics by installing additional absorbing material following the same "echo theory" design approach. In order to study the consequences of this design theory, four configurations of this concert hall have been numerically reconstructed. Through calibrated simulations, it was shown that in the case of the Palais du Trocadero, design decisions based on "echo theory" had a positive effect on the acoustics; however, due to the many curved surfaces, echoes, and sound focusing, the acoustic conditions remained poor.