Abstract: A hearing aid device is provided in which wireless data transmission and reception are established between a first hearing aid and a second hearing aid, worn one on each ear, wherein in a case where wireless transmission and reception are not possible, the first hearing aid and the second hearing aid are switched from a liaison operation mode in which both hearing aids are interactively adjusted to a solo operation mode in which each hearing aid is independently adjusted. In a case where wireless transmission and reception are possible, the first hearing aid and the second hearing aid are switched from the solo operation mode to the liaison operation mode.

Abstract: A hearing aid device is provided in which wireless data transmission and reception are established between a first hearing aid and a second hearing aid, worn one on each ear, wherein in a case where wireless transmission and reception are not possible, the first hearing aid and the second hearing aid are switched from a liaison operation mode in which both hearing aids are interactively adjusted to a solo operation mode in which each hearing aid is independently adjusted. In a case where wireless transmission and reception are possible, the first hearing aid and the second hearing aid are switched from the solo operation mode to the liaison operation mode.

Abstract: An acoustic echo erasing apparatus which generates a pseudo-echo component from an audio reception signal (a vector x.sub.1) using an adaptive filter, and removes the pseudo-echo component from an audio transmission signal (a vector y). The apparatus extracts a feedback component depending only on the audio reception signal from the audio transmission signal, and passes the audio reception signal through the adaptive filter to generate the pseudo-echo component while setting a transfer characteristic of the adaptive filter in accordance with the feedback component.