An objective study of the steady-state interaural time difference (ITD) was performed on a manikin comprised of a head and torso. Data were taken for both a bare and clothed torso. The measured ITD’s correspond reasonably accurately at the low and the high frequencies to the computed theoretical values for a rigid sphere of an effective radius a. The theoretical ratio of the low-frequency (<500 Hz) ITD to the high-frequency (≳2000 Hz) ITD is 3/2. The measured ITD is a minimum between 1.4 and 1.6 kHz for angles of incidence, ϑinc, of sound between 15° and 60°. At both the low and the high frequencies the data can be expressed by universal curves when the ITD is normalized by (a/c0)  sinϑinc, where c0 is the speed of sound in air and ϑinc is the angle of incidence. Both the steady-state ITD and the interaural sound-pressure-level difference (ILD) show differences between measurements made with the bare torso and those with a clothed torso. These objectives results support the subjective measurements of past experiments, which showed that in man there was no localization improvement below approximately 500 Hz, poor localization between 1000 and 2000 Hz, and a change in the localization cue around 1400 Hz from ITD to ILD.

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The sound-pressure-level transformations from a diffuse sound field to the head surface and the torso surface were measured. Transformations were measured on a manikin and on two subjects for frequencies between 0.2 and 10.0 kHz using 1/3-octave bandwidth random white noise. The pressure-level transformations to the center of the concha volume and to the ear canal entrance as well as to a microphone in an earlike coupler (using a manikin and six different-sized pinnas) were also measured. the maximum gain at the coupler microphone is approximately 15 dB at 2.7 kHz. This transformation to the head and torso surface depends strongly on the distance between the microphone and the heard or torso, and on the absorption of the head and torso, but not on the fine features of the head. Variations in pinna size have their greatest effect on the pressure levels in the outer ear above approximately 6 kHz, where higher-order acoustic modes are strongly excited in the pinna.

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Published and unpublished data on sound pressure distributions about the human head and torso were collected and analyzed. The results of the analysis are presented graphically. The data include measurements on both humans and manikins in both progressive wave and diffuse fields. The results can be used to aid selection of locations for the microphones of noise dosimeters and hearing aids and design of spectrum shaping circuits for these microphones. An appendix discusses procedures for determining whether it is appropriate to assume a progressive wave or diffuse field when these data are applied to actual situations in the field.