Abstract: It is of significant importance for adaptive active noise control within enclosed space to determine appropriate number and locations for error sensors. In this paper, the problem of optimum arrangement of error sensors is investigated for achieving maximum noise reduction under condition that the secondary source arrangement has been specified. It is shown by theoretical study and computer simulation results that the criterion of the errors sensor arrangement is similar to that of the sencondary source arrangement. Then,in order to keep maximum noise reduction and minimum number of error sensors,an approach for error signal interpolation is proposed.