Timo62 - Because the amp in the 2Wq rolls in, 1st order, below 80Hz, reaching full output at 40Hz and below, and the high pass filter rolls off below 80Hz, first order, your mains should be able to output smoothly down to about 40Hz or below. If not, you might get a dip in power response in that 40Hz zone. But if you speak with Richard Vandersteen, there may be a work around, but I don't know. I think the M5-HP battery powered crossovers are hinged at 100Hz instead of 80Hz, as they were designed for the Model 5 rather than the 2Wq. Richard Vandersteen told me how to set the dip switches inside the M5-HPs so that the hinge point of the roll-off would be 80Hz, as required by the amp in the 2Wq for flat response.
Bob - My 2Wqs are in the corners, behind and outside the speakers, about 2.5 feet away. Before I had two, I had one, in one corner. I never had a localization issue with this setup. YMMV, I guess.
Halcro - The in-line filters are 1st order, "elbowed" at 80Hz, so they are only down 6dB per octave, meaning 40Hz. That's still a significant amount of signal for the main amplifier(s). FWIW, the Vandersteen in-line crossovers are good, but not totally transparent. A great upgrade is to the M5-HP crossovers, which, IME, are more transparent, and provided subtle, but easily heard, improvements in soundstage openness, imaging, and transient reproduction.
