Statistical Energy Analysis is an accepted method for NVH model development at high frequencies. This paper explores hybrid methods to expand SEA to the mid and low frequency range where the assumption of high modal density is not valid. The newly developed hybrid method is particularly useful for structure-borne noise and vibration studies. The method is based on use of mobility functions to improve calculation of power input, modal densities and coupling factors. Comparison of the hybrid model predictions with measured data show good agreement down to 100 Hz.