This paper presents a new method for noise source identification in a multiple noise sources environment where the noise sources may be coherent to each other. It is found that the major characteristics proportion of the noise source is generated in vibration of forge machine by using multi-dimensional spectral analysis. This analysis is modelled as a multiple input/single output system when the noise generating system of forge machine is very complicated. In this analysis the concept of residual spectral analysis and the partial coherence function are applied. For contributions relation-ships between noise sources and radiated sound pressure are computed by micro-computer system. Finally, overall level for radiated sound pressure obtained by multi-dimensional spectral analysis are compared with those measured.