Solved by superunification in post #2 
              
              
                I’m not sure of the motivation for this ‘unfolded’ tensor. The data is 99.5% redundant, and the 200-sample window can be created at train-time from the audio-data tensor. Just take a slice audio[i:i+200] of the 8m audio tensor, and audio[i+201] as your target. 
The only extra ingredient, then, is th…