I have a problem with running the main speakers full range with only the subwoofer(s) bandlimited. IMHO, one of the advantages of using a subwoofer is to keep those large excursion low frequencies out of the main speakers, because they have an adverse effect on the midbass which the main speakers produce.
Also, I question the use of low (50) frequency crossover rather than high (90). Most people look at how low the main speakers go, and set that as the crossover. I contend that it is just as valid to look at how high the SW goes, and set that as the crossover. Of course this depends on your SW capabilities. In my case, I have selected 90 Hz over 50, and 70 which I have tried out. My main speakers, MG 1.6, can go to about 40 Hz. Of note is the fact that my six driver SW system includes three 15 inch JBL drivers that can go up to 800 Hz.
Also, I question the use of low (50) frequency crossover rather than high (90). Most people look at how low the main speakers go, and set that as the crossover. I contend that it is just as valid to look at how high the SW goes, and set that as the crossover. Of course this depends on your SW capabilities. In my case, I have selected 90 Hz over 50, and 70 which I have tried out. My main speakers, MG 1.6, can go to about 40 Hz. Of note is the fact that my six driver SW system includes three 15 inch JBL drivers that can go up to 800 Hz.