Eric doesn’t publish anything but this for the DI speakers:
20Hz-30kHz frequency response
±1dB deviation from 70Hz-20kHz
Personally, I would like to know what the ± is for 20Hz. I suspect it is more than -3dB.
Based on that, you would not want the crossover frequency to be higher than 70Hz and probably a lot lower. I would not crossover at all and just add a single subwoofer. Then see how that sounds.
20Hz-30kHz frequency response
±1dB deviation from 70Hz-20kHz
Personally, I would like to know what the ± is for 20Hz. I suspect it is more than -3dB.
Based on that, you would not want the crossover frequency to be higher than 70Hz and probably a lot lower. I would not crossover at all and just add a single subwoofer. Then see how that sounds.