Reply to comments on 'Absorbing surfaces in ray-tracing programs for coupled spaces'

摘要

The influence of diffuse reflections as calculated with the Epikul model can be found using the CATT-Acoustic ray-tracing model as well. However, to attain similar results the diffusion factors in Epikul should be chosen much lower than in CATT-Acoustic. Epikul predicts a mean free path equal to 4V/S in long, rectangular rooms for both specular reflections and pure diffuse reflections. When "some" diffusion is involved, a decrease of the mean free path is found which is of the order of 5%. When a non-rectangular room is used, an increase (which may be as high as 15%) was predicted. It would require much more research to give a definite answer to this problem, but for the moment we are not convinced that the mean free path will always be equal to 4V/S when diffuse reflections are involved in non-rectangular reverberation rooms. There is a huge influence of diffraction when sound travels through a gap at frequencies that are low compared to the dimensions of that gap. However, due to the combination of reflection and diffraction, the actual results from ray-tracing models are small compared to results from measurements.