I did try running them swept up to ~16K or so... pretty much followed the response found online on numerous forums... hence the panasonic supertweeter... down lower I didn't need as the peerless midwoofs are smooth up to > 1Khz and have plenty of wallop (>108dB @ 15 feet listening position)...

rather than pushing the RD75's w/eq, I added the ATC neoplanar 25's I found on ebay for ~$175 ea. they're good past 20Khz, @ ~92 - 93 db/w.. handle 150W RMS...had to pad them down abit to match the RD75's.

I would have probably built using only the neoplanars had I found them first, but this setup sounds incredible as is.. so I'm a happy camper... keep your eyes out for these planars... not withstanding the nay-sayers... I can never go back to pisstonic cone speakers (other than bass and subs) after building and hearing these line source dipoles... the imaging is staggeringly rock solid and lifelike...