I too have a 14x25 room, but it's a bit asymmetric, and because there's a 7' grand in the front, I've been forced to set up a 7.5' triangle about 10 feet out from the front wall. Sidewall splatter is tamed by stuffed furniture with throw pillows propped on top to stifle window and fireplace reflections. Wall-to-wall with a pad is absolutely CRITICAL
(train the damned puppy and get one of those child barriers for the doorways in the meantime if you have to!).
I like the short wall placement, as with a nearfield setup the room is less involved, and the stage is incredibly deep!
You may be able to get away with a throw-rug in front of and between the speakers if you set up in the nearfield, too. I just think your room is WAY to live for any other placement. The brightness is due to all those reflections and resonances. A warm cable won't help much, although it's not a bad idea.
Alhough I don't fully ascibe to the acousticians' "deader is better" rule fully, I find it's a better starting point then a "shouty" box! Good luck.