Throughout the development of engines, it is important to analyse their acoustic radiation to get insight in which parts or auxiliaries are important noise contributors. Different techniques are available for this purpose. Acoustic holography has become more and more feasible as an alternative to sound intensity measurements. This paper compares sound intensity and acoustic holography analysis performed on measurements taken on an engine running on an engine test cell. Care was taken to have identical test circumstances. This provides a perfect database to make a comparison between the two techniques. Sound intensity scans enable to obtain a 2-dimensional view of the acoustic field radiated by an engine. Acoustic holography on the other hand provides a 3-dimensional image of the acoustic field by measuring phase referenced sound pressures in a plane. Both techniques are discussed regarding acquisition as well as analysis issues. Especially the choice of the set of reference signals for acoustic holography is addressed. Results of both techniques are compared.
