I wrote a full review of digital filter design methods matching an analogue prototype (2nd order sections), overcoming the frequency warp against Nyquist. I collected, implemented and tested a few other ones. Among them, the recent method found by Yuriy Ivantsov is probably the most interesting.

https://ldesoras.fr/doc/articles/decramp-comp/

Of course all these methods can be combined with light oversampling (2×) to achieve almost perfect results.

#audio #dsp #filter #filtering #equalizer #biquad