Improve the consonants of 'dei' and 'dao' syllables in yali-lower by amplification and by copying the best 'd' sound to the other tones, to make it clearer that a 'd' is there. Still couldn't get the 'd' of dao1 very clear though, and I'm still not happy with some of the 'den' and 'deng' ones especially 'deng1', but there doesn't seem to be enough clear source material to get that any better on yali-lower. One thing that does seem to help a tiny bit though is inserting a tiny bit of silence at the start of deng1 so it's more clearly separated from whatever the previous syllable was (e.g. de5)