Cross over question

Hello everyone. Not being completely satisfied with how the system was sounding in 2 channel mode (our system does double duty with HT and music) we decided to have someone trained in the Sumiko method take a crack at it. We have a Marantz 8805 into a Mc 8207 amp. Speakers are Kanta 3s with Rel S510 subs.  He did an amazing job and the music now is much richer, fuller and less forward. My only concern is he turned off the crossover setting in the Marantz which has allowed the Kanta 3s to deliver deeper bass than I thought they could do. Are the woofers in danger of damage with the crossover off? Should I turn the setting back on? The setting was set at 80 htz. He adjusted the sub crossovers individually by ear. Thank you for your advice