Consolidating Compression and Revisiting Expansion: an Alternative Amplification Rule for Wide Dynamic Range Compression

The fitting process of modern compression hearing aids is becoming increasingly more complex as the processing capabilities of modern hearing aid devices continue to grow. However, a simplification of hearing aid parameters would enable more accessible user customization of a hearing aid, which is especially applicable in the growing field of over-the-counter devices. This work presents an alternative to the conventional compression input/output curve which consolidates numerous parameters while retaining equivalent performance, and revisits the concept of expansion in compression devices. The consolidated amplification rule is a continuous function without knee points, controlled by two parameters – gain and compression ratio. Experimental results have shown that the expansion properties of the function reduce amplification of low-level ambient noise by up to 4 dB, and improves signal-to-noise ratio by up to 1 dB (25%) in moderate noise conditions.