RAAL ribbons are great and the 70-20 can be crossed over as low as 1800hz in a 2-way. However, compared to a dome with good excursion they lack some dynamic punch in lower mids, so generally they are better off in a 3-way because of this.
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?