Not sure I understand the question. If you set them to "small" all the bass will go to that big subwoofer in the front and (as always, in theory) you can't tell where in the room the bass is coming from anyways.

If you don't have a sub, the bass from the surrounds will go to your mains as long as your receiver supports it (HKs don't but everything else seems to).

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8