2.5 way versus 3 way

[Mos Fetish]

I'm a little confused. Perhaps someone can help me.

A 2.5 way is where the second bass/mid driver rolls off higher in lower bass, right? Say, rolling off at 100hz whereas the other driver may go down to 35hz. Both drivers however go all the way up to the tweeter's crossover. OK?

In the equivalent 3 way design the mid driver might roll off at 300hz and be solely responsible for the midrange.

So, is the point of a 2.5 way design to give bass extension or to boost midrange, or neither.

Thanks in advance.

 

[JoeBob]

In a 2.5 way, both bass drivers would go as low as they could, but one would be crossed over at the tweeter xover point, while the other would be crossed over lower. This is done for added bass.