I don't know, but it could be a number of reasons why my 4343 seems to sound a bit muddled in the mid to low-highs to me. Marty Paich orchestra versus a piano trio. What I'm aiming for is to have more clarity and definition in the vocal range, as well as more delineation when playing sources with broader range - i.e. Thank you to both Ian and porschedpm for your informative replies.
Ultimately I believe bi-amping is the best way for the large format studio monitors, but it takes a lot of adjusting and comparison listening to really get it right. I'm convinced that bi-amping is certainly not the cheapest way to go and if you try to economize too much, and introduce a weak link into the system, you may be better off not bi-amping at all. What I found was that the active xover can either make or break your bi-amped set up. What I found was that I lost a little bit in bass authority and definition, but it was more than made up by the improvement in the clarity and detail in the mids and highs. Then another LH forum member dared me to try my system non-biamped running thru just the 250w/ch amp. I thought it all sounded great and was an improvement over the the non-biamped set up. For the active xover I was using an Ashly XR1001.
I was using a Mac MC-150 (150w/ch) and a Pass X250 (250w/ch) amp. In my own case, I first bi-amped my 4343B's well over a year ago. In other words, as you add different components, be prepared to critically listen to your system with and without bi-amping to determine what sounds better to you. I would suggest you approach bi-amping the 4343B monitors with the thought that bi-amping can improve your system but it's not guaranteed. Here's a generic article on the basics of biamping: Here's a copy of the 4343 brochure although there's not much on bi-amping in there: