In this paper, the authors propose a method of enhancing sound in a selected region by controlling multiple sources. The physical variables. of enhancing sound have not been well defined, but we may consider basic acoustic variables such as acoustic potential energy, sound power or intensity. A method of maximizing sound potential energy was found to be very straightforward [J.-W. Choi and Y.-H. Kim, J. Acoust. Soc. Am. 111, 1695 (2002)]. In this paper, the authors attempt to control the sound power or intensity of a zone in a desired direction. It is noteworthy that control of the direction and magnitude is needed to enhance the sound intensity. This control requires a new definition of the, direction and magnitude of spatially distributed intensity. For this purpose, the authors introduce two different kinds of cost functions, and the theoretical formulation based on the new definitions show the possibility of maximizing the sound intensity of a selected zone in a desired direction. (C) 2004 Acoustical Society of America.