The acoustic pressure field alongside KEMAR's head with a view towards in situ hearing aid tests

Abstract

To simulate actual usage conditions, it is expected that the frequency response of heating aids will be measured on the head of the KEMAR manikin over the frequency range of 0.2 to 8 kHz. The acoustic pressure around the head can vary rapidly with both the frequency and the location. In order to compare and interpret the hearing aid response at various frequencies and locations on the head, it is necessary to precisely know the pressure variations. The amplitude and phase of the acoustic pressure were measured in increments ranging from 2 to 5 mm alongside KEMAR's head with frontal sound incidence. The acoustic driver was located in front of EMAR at a distance of 1.0 and ∼ 3.5 m from the ear canal axis. The test frequencies were the octave band center frequencies from 0.5 to 4.0 kHz and the third octave band center frequencies from 4.0 to 8.0 kHz. It will also be shown that pink noise of 6% and 29% at 6.3 and 8.0 kHz has a smoothing effect on the acoustic pressure variation with location.