I disagree, It's not a good idea to have multiple crossover points. Bass is not dedicated to the LFE. It is often common among all three front channels + LFE. The problem (aside the inherent phase issues) is summing a mono bass signal from the different crossover points. If your center channel is crossed over at 100 HZ and your mains are crossed at 60Hz then the bass from 60-100 will be 6db louder than the original level because the mains and the sub will both be voicing it. So, after the summing, the combined level has to be attenuated back to the original level. Good bye signal to noise ratio and hello phase irregularities.