There’s only so much you can do to deal with a room, especially at low frequencies where traps have to be huge. The dipole approach of the Orion (Linkwitz’s design with open baffle midrange with front and rear firing tweeters and H-frame open baffle woofers) has much more consistent power response (sum of all on and off-axis output) from low to high, which improves the consistency of the direct and reflected sound.
http://www.linkwitzlab.com/orion-rev4.htm
If the reflected sound is delayed by a sufficient (but not too great) amount and is sufficiently similar to the direct sound then the brain ignores it.
Another approach pioneered by Earl Geddes uses big pro-sound woofers (12″ in his least compromised current model) crossed over to huge oblate spheroid waveguides. These are placed firing diagonally in, with their tightly controlled dispersion causing hugely reduced wall reflections. As you can’t control the dispersion at low frequencies (unless you use arrays the size of your house) the lows are then produced by multiple active subwoofers, each with independent control of level, cut-off and phase – by having multiple subs you can energise all the different room modes more evenly, resulting in smoother LF response. The main speakers are in sealed enclosures and run without highpass filtering so they too act as LF sources up in the 80Hz+ region.
http://www.gedlee.com/abbey.htm
http://www.gedlee.com/Subs.htm
Unfortunately the Gedlee designs don’t fit terribly well in small western European homes, being better aesthetically suited to huge US or Scandinavian houses, even though small rooms are where the acoustic benefits are greatest! Hopefully we’ll see mainstream manufacturers start to focus more on polar response because it matters far more than people realise.
