Sound Source Localization of Reflective or Diffractive Field near the Sound Source by means of Near-field Acoustic Holography

The sound source localization can be carried out by the Near-field Acoustic Holography (NAH), and optimal treatments against the machinery noise are planned out from these results. In this work, a handy 2-D microphone array, which has 64 microphones, and is combined with real-time acquisition system, is proposed for on-site measurement of real machinery noise. This handy array can be moved easily around the object, so measurements and analyses at various viewangles by the NAH are carried out sequentially. Reflection and diffraction because of the shape of machinery often complicate the sound field near the sound source. So in this report, the results of sound source localization of such a complicated sound field by the NAH with the handy 2-D microphone array are investigated experimentally by means of a model of machinery noise. It is shown that this method is effective and practical for the source which yields the complicated sound field.