Part I - B&C coaxials open baffle on top of closed box woofers
This is a concept I like a lot these days. Off course there are many ways to make great sounding speakers, this is definitely one of them. I like open baffle speakers, especially in midrange. On the other hand to achieve deep bass with open baffle is difficult. So the woofers are in closed box, which make speakers relatively slim.
I obtained 12" B&C coaxials from parts express for $50 each, the woofers are 15" Jamo for just $15 each. So for just under $100 per side one can put together extremely good sounding speakers. They are clean, coherent, dynamic and efficient. Few watts is plenty. They would, just like many other speakers, benefit from bi-amplification, which is going to happen soon.