Xu J., Shimada S.

Room acoustic modelling software packages, such as CATT Acoustics and ODEON, have been widely used during the design stage of rooms to provide predictions of acoustic parameters. Using such packages, rooms can be modelled on the basis of their coordinates. The main drawback of this method is that it is very time-consuming so to expedite the room modelling process the facility for importing the 3D CAD models is available in CATT Acoustics and ODEON. However, often the imported models have some holes, which will result in rays leaking out of the room model, and the amount of time required to detect and fix these holes may be substantial. Both programs advise users to make room models watertight but no results of investigations of the effect of leakage on the accuracy of results are available. In the initial concept design stage what the architect usually requires is the quick acoustic feedback to his/her scheme for the room so it is important to determine whether to invest a large amount of time in making the room acoustic model watertight. The present paper uses a church auditorium with simple room geometry to investigate the sensitivity of predictions to the positions of holes and the extent of leakage and results indicate that the difference between predicted room acoustic parameters on the basis of a watertight model and those on the basis of a leaking model can be within the subjective difference limen and therefore can be insignificant.