Experimenting with Speaker Room Placement

Hi - was having troubles with my room, which is 12 wide by 20 long, so logically I was thinking put the speakers on the shorter 12ft wall and sit back about 11-12 feet so I'd have more room between listener and the speakers. But tried my PSB towers, PSB bookshelfs, Bose Bookshelves, JBL bookshelves (and tried PSB sub with each) and that placement was always boomy bass and fatiguing sound. Just didn't sound right. 

So I tried setting up speakers on the long wall, the 20FT wall. It looks odd since I'm sitting pretty close to the speakers, about 7-8 Ft vs. 12 Ft, and the speakers are right up against the wall, and my listening chair is right up against the opposite wall. But it's more listenable, and bass seems tighter. Both the floorstanders and the bookshelves sound better. 

I'm still trying to purchase a new pair of speakers for this room (the other speakers mentioned were just borrowed from other rooms and from my home theatre setup). 

So wondering if others have experimented and found the long wall is better? It's more of a near field listening experience and looks odd having large towers that close to the listener. Would this position get fatiguing after a while? Should I treat the back wall with something since that wall is right behind my ears? What speakers are you using that seem to work well in this type of close listening setup?  If I place the speakers back on the shorter wall, is my issue that I need bass traps along the shorter wall to tighten the bass? 

Thanks very much for any guidance!