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.
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Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner
TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv
Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner