Input features are 40 mel-scaled log filterbank enegries (FBanks) computed every 10 ms with 25 ms window, concatenated with deltas and delta-deltas (120 features in vector). We also tried to use spectrogram and experimented with different normalization techniques. 
 Question: What features do they experiment with?
40 mel-scaled log filterbank enegries (FBanks) computed every 10 ms with 25 ms window deltas and delta-deltas (120 features in vector) spectrogram