In summary, we provided a brief theoretical justification to the direct use of microcanonical ensemble simulations for efficient computations of vibrational spectra. To further improve the efficiency, we proposed an NVE -eqp method in which all modes start with the same amount of energy. With the gas phase methanol molecule as an example, we showed that the NVE -eqp method can reach spectrum convergence faster with less total simulation time and thus is much more efficient for vibrational spectrum calculations for gas phase clusters.