Reply To: Use LR Output as HiPass + 1 Mix out for Sub

[AndreasModerator]

You probably want to read these threads first:
use equaliser to put low pass filter in place
Feeding subs via Mix 5-6 using LPF, as a substitute crossover
The first thread also contains some frequency plots showing the difference between a faked (using EQ) and real crossover.
If you just want to protect your tops, this may work. If you bought a Qu in order to make great sound, stay with or maybe upgrade your crossover.