Acoustics of a traditional half-circle ampitheatre

I made the form in revit and uploaded it into Ecotect. Although Ecotect recommends making the forms without importing, it worked fairly well (largely because of the simplicity of the shape). Here you can see rays spreading out spherically and randomly from the source. The Ecotect model demonstrates that the concave curves of the ampitheatre are focusing the sound inwards back to the source, creating an unsavory acoustical environment. As mentioned before the theatre also would generate a picket-fence echo, which cannot be calculated by Ecotect. To avoid picket fence echo one must not make evenly spaced reflective surfaces. Next I will show how the opposite of this shape, a convex curve,distributes sound. I will also look into the acoustical properties of an ellipse to see if it upholds the even sound diffusion qualities of a circular curve.