An adaptive filter-bank equalizer for speech enhancement

A digital filter structure is proposed for fixed or adaptive spectral modification of speech and audio signals, which is derived from a reference filter bank. Main applications are audio equalization and noise reduction. The signal is filtered in the time domain, while the filter coefficients are calculated in the (short-term) frequency domain. In comparison to the usual short-term spectral-domain processing, the proposed structure exhibits distinct advantages with respect to signal delay, prototype-filter design, and complexity. The algorithm allows for uniform, as well as for non-uniform spectral resolution.