In this paper, two methods for improving the performance of DSBC (Dynamic bit allocation Sub-Band Coder) are proposed. One is to modify the bit allocation algorithm since conventional dynamic bit allocation algorithm is computationally heavy, while the other one is to weight the subband to reduce hissing noise. Instead of inserting the Gaussian noise in regeneration of empty band, the subband weighting method is to utilize shaped subband signal as empty band signal. The simulation result shows that computational complexity is reduced about 10%, and perceptual hissing noise is suppressed noticeably.