I have 2 channels, but mainly only post on one. I tried to target multiple different audiences to see if I could increase subscribers, however I feel like having multiple different channels makes it harder to think of creative video ideas for each one. For example, if I only have one channel I already have to think of 2 video ideas for that channel, but adding an additional channel makes me have to think of 4 videos a week! In my opinion, having 1 channel with 2 maybe 3 different niches is good. I keep trying to narrow my niches down as I go, but for the most part, having a few different things has worked somewhat for me.