[colanderman]

Nice! I've used a homegrown CQT-based visualizer for a while for audio analysis. It's far superior to the STFT-based view you get from e.g. Audacity, since it is multiresolution, which is a better match to how we actually experience sound. I have for a while wanted to switch my tool to a gammatone-filter-based method [1] but I didn't know how to make it efficient.

Actually I wonder if this technique can be adapted to use gammatone filters specifically, rather than simple bandpass filters.

[1] https://en.wikipedia.org/wiki/Gammatone_filter

[mofeien]

If you already have the implementation for the CQT, wouldn't you just be able to replace the morlet wavelet used in the CQT by the gammatone wavelet without much of on efficiency hit? I'm just learning about the gammatone filter, and it sounds interesting since it apparently better models human hearing.