Audio signal processing by filters self-adjustable to spectral power distribution

This paper presents two-channel and three-channel complementary filter banks self-adjusting to the power spectral distribution of its input signal. The filter banks are based on EMQF or Butterworth double-complementary filter pairs. The adjustment of the 3dB-crossover frequency is achieved by a simple tuning algorithm that is suitable for the EMQF and Butterworth filters. A new algorithm for changing the 3dB-crossover frequencies as a function of the power spectral distribution of the input signal is proposed. The algorithm is based on the well-known binary search algorithm and is simple to implement in non-real time applications.