Subband perceptual audio coding aims at providing the best subjective quality by decomposing the input signal into adjacent subbands. Every frequency component is then separately coded with a different number of bits in order to properly shape the quantization noise density power spectrum. In this letter, an optimum bit allocation algorithm is presented. As well as being applicable to either uniform or nonuniform frequency decompositions, it allows us to take into account the nonideal selectivity of the reconstruction filters. The effects of leakage for both short and long FIR filters have been investigated referring to a wavelet packet subband decomposition.