EFFECTS OF MICROPHONE POSITION AND AZIMUTHAL SOUND-INCIDENCE ANGLE ONPEAK SOUND PRESSURE LEVEL OF ACOUSTIC IMPULSES

A laboratory study was conducted to compare peak A-weighted sound pres sure levels measured at four locations on a Knowles Electronics Maniki n for Acoustic Research (KEMAR) to those measured in the same sound fi eld without KEMAR present. Acoustic impulses were generated in a parti ally-reverberant room and measured using a sound level meter set to '' peak hold.'' Measurements on KEMAR were made at four azimuth angles wi th the microphone mounted at the eardrum, ear level, shoulder, and che st, for a total of 16 measurements. As expected, peak sound pressure l evels measured at the eardrum consistently exceeded the peak sound pre ssure level measured in the reference sound field with the manikin rem oved due to the pressure gain of the external ear. Peak sound pressure levels measured at the chest approximated the reference sound field m easurements within 1 dB. When the influence of room reflections was el iminated from the measured peak sound pressure levels, variability inc reased dramatically at all microphone positions and azimuth angles.