8When these matters are arranged with great care and skill, particular attention must be bestowed on the choice of a place where the voice falls smoothly, and reaches the ear distinctly without an echo. Some places are naturally unfavourable to the diffusion of the voice. Such are the dissonant, which in Greek are called κατηχοῦντες; the circumsonant, which the Greeks call περιηχοῦντες; the resonant, which they call ἀντηχοῦντες; and the consonant, which they call συνηχοῦντες. The dissonant places are those in which the voice, rising first upwards, is obstructed by some hard bodies above, and, in its return downwards, checks the ascent of its following sounds.
2The circumsonant are those where the voice, wandering round, is at last retained in the centre, where it is dissipated, and, the final syllables being lost, the meaning of words is not distinguished. The resonant are those in which the voice, striking against some hard body, is echoed in the last syllables so that they appear doubled. Lastly, the consonant are those in which the voice, aided by something below, falls on the ear with great distinctness of words. Hence, if due care be taken in the choice of the situation, the effect of the voice will be improved, and the utility of the theatre increased. The differences of the figures consist in this, that those formed by means of squares are used by the Greeks, and those formed by means of triangles by the Latins. He who attends to these precepts will be enabled to erect a theatre in a perfect manner.