By the way, when making a module, channel mixing is just that. Mixing the notes for several different channels into 1 channel. The result doesn't always sound exactly the same, but sometimes, it does sound close enough. Usually, when mixing channels, if notes overlap, 1 channel must be proritised over the other. The best channel to prioritise is the channel that is the most important of the 2 at each time they overlap. Practising this would be a good thing to do. Trust me, I have practised this too. I was able to modify Ghidorah's Toilet Story 4 to use 8 channels instead of 16 and I've tried my best to make it sound like the original.