Ken and Adrian,
It's been so long, I can't remember! That used to be the M50 design, but it may have changed. I'll ask Ian.
In effect, Ken, what you say is also correct: the 2 1/2 way does use a different crossover arrangement for each woofer. It's just that on the second woofer of the M50, it's a mechanical/acoustical crossover, so it will carry some midrange content (no low-pass on the second woofer). The same arrangement is used on the M3's single woofer. It's allowed to mechanically roll off rather than using an electrical network. The M3 still has a crossover with a high-pass filter to keep low frequencies out of the tweeter. There just isn't a low-pass on the woofer.
Regards,
Alan
