@article {Tanaka:2023:0736-2935:2164, title = "A diffuseness of a sound field in the domains of spherical harmonics and plane waves", journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings", parent_itemid = "infobike://ince/incecp", publishercode ="ince", year = "2023", volume = "268", number = "6", publication date ="2023-11-30T00:00:00", pages = "2164-2171", itemtype = "ARTICLE", issn = "0736-2935", url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/2023/00000268/00000006/art00018", doi = "doi:10.3397/IN_2023_0319", author = "Tanaka, Tatsuhiro and Otani, Makoto", abstract = "Sound field diffuseness plays a key role in room acoustics. Although several attempts have been made to characterize diffuseness quantitatively, how to quantify the extent of diffuseness has yet to be understood. This paper considers a directional diffuseness of a sound field from a viewpoint of statistics. Using an existing approach to the evaluation of diffuseness that employs a covariance of electric acoustic signals in the spherical-harmonics domain, a limited-degree directional diffuseness is formulated. In addition, a spherical design is used to model the diffuse sound field composed of finite number of plane waves. The formulation and the model can contribute to a better understanding of the evaluation of the diffuseness. Results also suggest that Gaussianity of a sound field in the spherical-harmonics domain can be interpreted as Gaussianity of plane waves in the diffuse field model.", }