Ditto what wid said. Hsu and SVS are much, much better than Klipsch.
And they have a few outstanding performers in the $400-$600 range
SVS PB10-NSD @ $429 is an outstanding performer. I have the earlier ISD version and it is very impressive. I get strong, quick and flat response down to 20hz, with useable response down to 17hz.
SVS PB12-NSD @ $600 is the PB10's bigger brother. Flatter and more extended response.
Hsu VTF-2 Mk3 @ $469. I can't personally speak to the performance of this one, but several board members can and it's gotten nothing but rave reviews everywhere I've looked.
Hsu STF-3 @ $479.
