Speech levels at the ear of a talker and their implication for a hearing‐impaired person taking part in a discussion

Abstract

Speech levels at the ear of a talker and corresponding levels at a listener's ear were measured near the ear‐canal entrance. Eight subjects, each serving both as listener and as talker, were tested two by two in an anechoic room at a distance of 1.5 m. Below 1000 Hz, levels at the talker's ear appear to be about 15 dB higher than at the distant listener's ear. Above roughly 1000 Hz, the head progressively shields the talker's ear and the level differences between talker's and listener's ear diminish at a rate of about 6 dB/oct. Weighted according to the articulation index, speech is a 9 dB more efficient masker at the talker's ear than at the ear of a listener at 1.5‐m distance. A voice interrupting at the same level as the primary voice is still intelligible for a normal‐hearing talker (speech‐reception threshold about −12 dB), but a hearing‐impaired talker is forced to choose between talking and listening. With a compression hearing aid, the chance of understanding an interrupting voice is even less, because the compression system will strongly act upon the listener's own voice.