If it's still a 2 1/2-way, you might be able to hear a bit more midrange/upper midrange content from the woofer with the mechanical/acoustical crossover.
By the way, an M50 was put into a double-blind test I was doing recently up at the plant. I don't have the rating sheet in front of me, but I remember writing down: "this is a very nice speaker. Very natural solo male and female vocals, but I wish it had a bit more detail on orchestral and choral works."
The other speaker in the comparison was a competitor's model that had so much detail, I called it "shrill".
Alan
