Design of Compensated Multi-Channel Dynamic-Range Compressor for Hearing Aid Devices using Polyphase Implementation
Ziyan Zou, Yiya Hao, Issa M. S. Panahi · 2018
Dynamic-range compression (DRC) is widely used in hearing aid devices (HADs) to reduce the wide dynamic range of input speech signal to match the residual dynamic range of people with hearing loss. Most compression systems use multi-channel compression to provide more effective and accurate solutions to match input signal with hearing-impaired people's audiogram. However, multi-channel compression introduces distortion to the system, and increases computational complexity. It limits the sampling rate and results in systems latency, hence, introduces difficulty realizing it in real-time. In this paper, a compensation filter is proposed to reduce the distortion, and polyphase implementation is applied to reduce the computational complexity. Objective and subjective tests are conducted to evaluate the quality and intelligibility of the output audio (speech) signal under different noise types and signal to noise ratios (SNRs).