This may have changed with newer receivers but there used to be a problem with setting the Xover to less than 80Hz. It had to do with the mix being designed (THX) to have an 80Hz Xover and setting the reciever Xover at say 60Hz would cause all the LFE info between 60Hz and 80Hz to get lost. I would think that newer receivers with individual Xover settings for each channel would have overcome this problem but I'd still check.