RTS Speakers and subwoofer settings

I have installed 7 of the RTS speakers. 4 - 105 rts (front and rears) one rts center and 2 rts fx as surrounds. I have it set up in my basement which is all sheetrock including ceiling with carpeted floor. I am running an Outlaw 7700 amp and an Integra 9.8 pre-amp. The sub I have is a Monitor Audio ASW 210 subwoofer.

All my speakers are set to cut just wondering what the recommended setting for the subwoofer to crossover should be. The room is rather large about 32 ft by 25 ft. with 8 foot ceilings. I can set the crosover on the sub to anywhere from 40 to 140 i believe.

Thanks for the advice in advance.