An Interactive Guide to the Fourier Transform

It's quite interesting that our ears implement a better-than-Fourier-like algorithm internally: https://arxiv.org/pdf/1208.4611

Article on how this might work (nonlinearity)

https://jontalle.web.engr.illinois.edu/Public/AllenSpeechPro...

Note the two electric circuit models figs 3.2 & 3.8