I am fairly confident I understand this part of this project. I was planning on having 16 bandpass filters with resonant frequencies ranging from 20Hz to 20kHz. Without getting into too much math behind the filters, I believe a 2nd order filter should be fine to use for this. However, I should note that I am planning for some overlap of filters but not when the gain is greater than the half-power frequencies (cutoff frequencies). This leads to filter n's lower cutoff frequency matching up with filter n-1's higher cutoff frequency and filter n's higher cutoff frequency matching up with filter n+1's lower cutoff frequency. With resonant frequencies at 20, 31.7, 50.2, 79.6, 120, 200, 317, etc., a quality factor, Q, of only 2.15 is needed, which a second order BP filter should easily accomplish.