I can see in my post that I wrote both bipole and dipole, but the speaker will be used as a bipole, and maybe I´ll try dipole just for fun.

The distance from the midwoofer and the horns are about 4,5cm, that´s a 1/4 wavelength of 1900hz.

Do you think I should use a crossover of 1900hz instead then ?

And what about putting the horns in series or in parallel ?