If you are not already doing so try using MFCC or MFE features, experiment with window size (typically 500-1500ms) and stride to balance temporal resolution and memory.
I tried MFCC with window size of 1200ms and increase of 200ms . beyond this the board starts rebooting non stop.
For now I have started to try other processing blocks like Spectrogram and next will be spectral analysis and raw data. I will train and test the model that can fit my board limits and have high accuracy in real world scenarios
Im still having a hard time understanding the Neural Network Architecture’s configurations and Im still studying on better sequence and blocks I can use to improve the models capability to classify sound and will still fit the board Im using
Hmm you can also try another configuration of blocks e.g. Spectrogram and Raw Audio see if that reduces the size a bit, but I’m not sure about the TTGO board, it may have some portion reserved for display?