I have multiple questions and most likely of basic knowledge nature. I need some help walking through all the speaker types for a room: Family Room Plan. I wish to start with the front speakers: fl, fr & center and will trickle through the other types later in this thread.
Note: The receiver is a Denon AVR-4400H, the selected subwoofer is an EP500. I am currently dabbling with a pair of M22 and one M2 for the center, all bookshelves speakers. I believe the speakers vintage to be the first version. Front speakers must sit on a bookshelf: Family Room Bookshelves, note: the current speakers will be removed.

I have recently learned that bookshelves speakers are not designed for bookshelves. It sounds to me like there is no speakers that where designed for existing bookshelves?
If you use a plug on bookshelves speakers does that make them equivalent to cabinet speakers?
Should I be using on-wall speaker in my bookshelves?
What changes could I expect if I upgraded to version 4 or possibly M5?

Thank you for your interest, more pictures of our Family Room.