CHARACTERIZATION OF A DIFFUSE FIELD IN A REVERBERANT ROOM

An efficient modal approach to characterize the diffuseness of the sou nd field in a rectangular room is presented. Using two simple descript ors, the correlation function and the spatial uniformity of the pressu re field, a practical and convenient tool is proposed to study the dif fuse field in the room. A precise criterion has been given in terms of the least permissible number of room modes to achieve an adequate dif fusion. It has been shown that the criterion is in great accordance wi th the well-known ''Schroeder frequency'' limit for the diffuse field. Detailed calculations of the correlation function are presented to sh ow the importance of the Delta k/k correction terms to the well-known sin(kR)/kR prediction. A new closed form for the correlation function is thus derived. A discussion about the importance of having more than one descriptors is also presented. It is shown that a diffuse field c an be established in a room with strong modal behavior under certain a ssumptions. (C) 1997 Acoustical Society of America.