The perception of internal circuit noise in hearing aids by listeners with normal hearing

Internal circuit noise in hearing aids is distracting to a listener and, if loud enough, may interfere with intelligibility, either by direct masking of weak components of speech or through the generation of undesired intermodulation products, which can also act as a source of masking. The objective characteristics of noise may be measured; however, wearers of hearing aids often differ in their subjective reporting of the perceived characteristics of the internal noise. This study reports on the results for four listeners with normal hearing of matching pitch and amplitude to the internal noise generated within a series of hearing aids. Results of these experiments showed that the listeners (a) primarily matched the perceived pitch of the noise to the frequency of their most sensitive hearing, and (b) matched the perceived level of the noise approximately to the total SPL noise level.