I agree with Chas...though my room is much smaller than yours, the 1070 does sound more powerful than the Yamaha 659 (which I had too). The speakers I had when I used the 1070 were much less efficient (~83 db) than I believe yours are and my room is carpeted but it filled the living room and adjoining dining room with sound.
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HT:
Pioneer VSX-1120
Salk Songbirds, SongCenter, SongSurrounds
Panasonic BDP-45
Outlaw LFM-2
2 Channel:
Red Dragon M-500 monoblocks
BAT-VK3i
Salk HT-1TL's
Apple TV
Beresford 7520 DAC
Surgex XS10