/diy/ - Do It Yourself

I'm making a bluetooth speaker, partially to understand audio and electronics better but mostly for the fun of it.
I have a few issues though;
1. are tweeters really just a voice coil with an x-material dome over it? Pic related
2. I'm using a crossover to seperate highs and lows, but have 4 Ohm speakers and probably 4-6 Ohm tweeters, the amp supports 4-8 Ohm. So if I have the amp at 4-8 Ohm range, then the crossover going to two speakers at most likely both 4 Ohm, will that work properly?

That's the important ones
3. 50W per audio channel, 40W speaker and 30W tweeter, how will it share that power? Because I think 30W for a single tweeter is insane, especially when it'll take away from the barely existing oomph the speaker already has.
4.1 do li-ion 18650's really need to be balanced at the same voltage first? I'll be connecting them to a charge/balancing board anyway.
4.2 such a board wont produce too much heat charging at 1A/5V right? Though I might need a better charger as that'd take 12 hours for 4 3000mAh 18650's

Many thanks in advance. If this works out you'll probably see me again sometimes, as well as in woodworking.