Constant Q Transform (CQT)
It would be interesting to implement a method for generating CQT spectrograms, in addition to the standard FFT spectrogram.
CQT is an alternative frequency representation of acoustic signals in which frequency bins become wider with increasing frequency (while the time resolution increases). CQT is described in this paper: https://asa.scitation.org/doi/10.1121/1.400476
Librosa has an implementation of CQT that we could use: https://librosa.github.io/librosa/generated/librosa.core.cqt.html