Most smartphones shift phases on the left/right channels to make it sound better in headphones (simulating bigger room), this means you can combine the two chan

Most smartphones shift phases on the left/right channels to make it sound better in headphones (simulating bigger room), this means you can combine the two channels (by connecting the positive wires or just wiggle a little in the headphone jack half way in) to extract the vocal track. Not as fancy as a CNN but I’m guessing it would be better to do something with the stereo information in preprocessing before training.