Using a mid-bass or a true mid-range

[Goodman]

Which is preferable for a tri-amped speaker? advantages and trade-offs?

 

[alex-z]

Usually a dedicated mid-range, something in the 2-4" range, so you get nice directivity matching to your tweeter even if the waveguide is small or not present.

You might use a mid-bass instead if you need a particularly low crossover point, like the Directiva R2 for example, which is around 200Hz AFAIK.