No way, go with the RF-83, maybe an RC-64 in addition, the center channel does add presence. As a guy who has grown up with Heritage series equipment, I see the RF series as a serious step in evolution. As an owner of both Heritage and RF series, I prefer the RF series for listening.
Geez, the Cornwall is a good efficient speaker w/alot of pesonality, but I think the RF-83 has much better detail and clarity in sound. Things move forward and although the Cornwall is 2db more efficient, the RF-83 is real progress, detailed and fine not just a bright, airy, loud sound. My mom has a pair of KHorns she bought for the house back in '62, I have owned both a pair of Heresy's and now I've had the Heresy II's for 22 years, I like my RF-52's and the RC-52 much better. Evolution in technology is a great thing.
Given the 2 db in efficiency, 100 db/1watt/1meter v 102 db/1 watt1 meter, either way you're moving a lot of air, the subwoofer for sure means you are reinforcing the lower frequency range of the RF-83, which has a better frequency response range than the Cornwall II. Although there hasn't been much evolution of the human ear, there certainly has been in the reproduction of analog wave lengths, the RF series represents some of the finest progress in the art of speaker making.
You have my vote on the RF-83's. Traditonalists may flame me, but when I got my RF-52's and RC-52, I put the Heresy II's under a blanket, and I haven't looked back. Heck, even my girlfriend likes them. Throw in an RC-64 for good measure with the money you save, you'll have a great sonic investment. You are setting up a home stereo, not a theater or PA system.
Either way, enjoy, I vote RF series.
Check out the link below:
http://myhometheater.homestead.com/splcalculator.html
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