I’m surprised that nobody mentioned Strathearns that address a lot of the problems mentioned. They are great from around 400 Hz on up. There is no need for a transformer if you put a couple of resistors in line with the amp.
Ribbon midrange pros and cons
Ribbon tweeters are fairly common on some high end speakers. ...they sound great.....can anyone tell me why ribbon midranges are hardly ever used by some of the best speaker companies. ..what are the pros and cons?