Al-Khafaji, S.J., Mety, P.K. and Al-Khoja, S.M. 2009. The Effect of the Geometrical Relations of the Opera Spaces on the Acoustical Performance. Iraqi Journal of Architecture and Planning. 1, 1 (Jan. 2009). DOI:https://doi.org/10.36041/iqjap.v1i1.415.