2.5 or 3 way; why one over the other?

@yogiboy 

A 2.5 way is missing 1 filter section. The "mid" has no high pass filter. 

Typically, the two woofers are the same, but Focal and possibly others, have used slightly different models. 

@erik_squires
Take a look at this Spendor. Does the mid have a high pass filter? What Focal is a 2.5 way? Am I missing something? If so please explain? Thanks!
https://store.acousticsounds.com/d/94323/Spendor-Spendor_D7_Stereo_Speakers-Speakers

@yogiboy 

In a 3-way the midrange has 2 filter sections. A high pass, and a low pass. 

In the case of a 2.5 way, the "midrange" is missing the high pass filter. 

That is exactly how you define the 2.5 way speaker system. 

The woofer and tweeter filters are otherwise the same in either. 

I'm not sure about Focal's current line up, but the Focal Profile 918's were an example of a 2.5 way. 

@erik_squires
Thanks for the info!

Because the two identical drivers sound more "of a piece".

Because it's cheaper to use two identical drivers than buying separate mids and woofers.

These and a hundred other reasons.