Room Treatment Help

My room is somewhat similar (13x14) and have got 11 GIK 244s (some with the wood things on the front - I forget what they're called) and other just bass traps. Two stacked in each front corner, three along the front wall in the middle, two at the 1st/2nd reflection points and two on the ceiling. And since my head is pretty close to the back wall, I took a few unused down comforters and folded them into a box to place behind my head.

I have quite a good selection of speakers and the treatment seems to work pretty well with just about all of them. 

Like others have suggested, I'd just contact GIK and send them a photo of your room and they will make suggestions as to which of their products will more than likely work well for your listening room. I bought my treatments a few years back and the prices were reasonable. The shipping sucked, however. 

@keeferdog 

Unless you look forward to all the time (a lot) and effort with trial and error trying to dial in your room just consult an acoustician. Jeff at HDacoustics is extremely good with smaller rooms  and can design the treatments required for a great sounding room. Also a corner set up like mine might give you the best sound with your room being almost square. Good luck!

keeferdog,
The echo sound when you clap your hands is likely flutter echoes between two hard parallel and untreated surfaces while the weird resonance is likely a room mode.  Treating a room your size is challenging due to its small size.  For example,  the theoretical decay time based on your room dimensions is just over 200ms which is the bottom limit of a generally accepted 200 - 500ms rule of thumb.  You don't want to line your walls with absorption which would lower it further and make listening uncomfortable like a quasi-anechoic chamber.  Instead, you could opt for bass traps of 6" thickness with a wooden facia to help preserve the mids/high frequency decay times to avoid an overly dampened room.  For the sidewalls, use reflective boards on an angle to deal with 1st order reflections from the closest speaker (L speaker->L sidewall) and farthest speaker (R speaker->L sidewall, and vice-versa) to create a quasi-reflection free zone while maintaining mid/high frequency energy.  Behind you in the corners and centre of the back wall place thick absorption panels, and place on either side of the centred panel 2D Skyline or 2D QRD diffusion panels of about 4" - 6" depth in order for you to sit 5-6 feet from them to help kill slap/flutter echoes.  On the front wall place 1D QRD diffusion centred on the wall with bass traps in each front wall corner.  With the bass traps having a wooden facia (See GIK Acoustics for example), sidewalls having angled wooden boards and the backwall a combo of diffusion+absorption that leaves the floor and ceiling to treat.  Place a small wool rug and underpad just large enough to capture the floor 1st order reflection bounce and 2D Skylines for the ceiling.  This combination of reflecton/diffusion/absorption of bass should go a long way towards improving your sound quality.