Actually you're a prime contender for open baffle or dipole spkrs, as Nsgarch aptly notes above. ANyhting else will prbably make yr life a misery (it'll be near impossible to control 300Hz downward).
Probably the best open baffle design is Linkwitz's Orion -- but that requires ~3k + diy or 6k ready made (that includes amplification; some consolation). It would be easy for you to get excellent sound in yr environment (possibly better than you'd get in an untreated conventional room).
Another open baffle choice at a more reasonable price is the Bastanis (www.bastanis.com) something or other -- which also requires a little diy.
As your room is large, appropriate stators would be frightfully expensive (think of big Soundlabs).
Probably the best open baffle design is Linkwitz's Orion -- but that requires ~3k + diy or 6k ready made (that includes amplification; some consolation). It would be easy for you to get excellent sound in yr environment (possibly better than you'd get in an untreated conventional room).
Another open baffle choice at a more reasonable price is the Bastanis (www.bastanis.com) something or other -- which also requires a little diy.
As your room is large, appropriate stators would be frightfully expensive (think of big Soundlabs).