There are mistakes on the constant k, T, PI filters which are now corrected on the previous posts

At your risk. Please also note that these filters have by definition the useful property that ZL times ZC equals R times R for any frequency. (the impedance of an inductance L is 2 times PI time L, the impedance of a capacitance C is 1 over (2 times Pi times C). It would be interesting to use as image impedance the output impedance of a Shure SM58, eg R+320 ohms and calculate suitable imductors, capacitors for various high pass cut of frequencies, or even a band reject filter of say 5Khz to convert the peak to flat as is done of the SM7 microphone?