The Sigberg Audio SBS.1 speakers are actually large (concept explanation)

[EJ3]

That kind of refinforces my point, you didn't list midbass!

But my question was focused on what the advantages of a midbass driver brings to the listener, I think I know the answer, but it's an educated guess, and I think stupid questions might help @sigbergaudio clarify his products advantages.

I did list mid bass, just not directly:
Subtract 63.33 from 250 = 186.67 Hz is the top of mid bass.
Add 63.33 to 60 = 123.33 the bottom of mid bass.
Therefore:
Mid Bass would be 123.33 Hz to 186.67 Hz
So divide BASS region (190)/3 equal 63.33.
Subtract 63.33 from 250 = 186.67 Hz is the top of mid bass.
Add 63.33 to 60 = 123.33 the bottom of mid bass.
One can round a bit an get 125 Hz - 185 Hz as mid bass.
So 125 Hz- 185 Hz is mid bass (unless you round it differently).