Deformation of a sound field caused by a manikin

Measurements of the deformation of a sound field by the presence of an anthropometric manikin are described. An approximate point source is placed at a distance of 3 m in front of the manikin at the height of the manikin's ears. In the horizontal plane at this height the resultant SPL is measured around the head at distances of 1 cm to 2 m, measured from the tip of the nose. The signals were pure tones at 1, 2, 4, 6, 8, and 10 kHz. It was found that the presence of the manikin caused changes in the SPL of the sound field of at most ±2.5 dB at a distance of 1 m from the surface of the manikin. Only over an interval of approximately 20 ° behind the manikin (i.e., opposite the sound source) did the manikin cause much larger changes, up to 9 dB. These changes are caused by destructive interference between sounds coming from opposite sides of the manikin. In front of the manikin, the changes in SPL at this distance are within ±1 dB.