Both the BLS and the Heresy III are rated to 57/58 hz. It is hard for me to imagine the rating since the Heresys have 12 in woofers compared to the BLS at a little more than 5 in. The BLS are true bookshelf speakers whereas the Heresys aren't, unless you like really big books. The Heresys are much more efficient (+12 dB) and will not need nearly the power that the BLS will to fill a room. I have always thought that big woofers are the way to go for big sound. I have a set of original Advent loudspeakers with a 10 inch woofers in 12 inch frames. They sound great, but they sound even better with a good sub backing them. I would go with the Klipsch and an LFM1 EX.