Electret condenser microphones for hearing aids

Specifications of ECM for hearing aids were compared with those of ECM for cellular phones and MEMS microphones. The size of ECM for hearing aids was almost the same as other microphones. However, as for microphones for hearing aids, high sensitivity, low noise level, low current consumption and low operation voltage were demanded compared with general microphones that are use with cellular phones and other devices. Frequency spectrum of sensitivity showed a peak in 2 kHz ~ 8 kHz in ECM for hearing aids while other microphones showed constant sensitivity.