Darkstar - read over my earlier response again. I think the details you need are included, but to try and clarify.
In a very small room like that, you need to cover most of your wall space with treatments. Not necessarily floor to ceiling, but 4 foot panels centered height wise with the speakers. In the corners you will need heavy bass trapping, again I'll recommend floor to ceiling GIK tri-traps in at least 2 corners, and preferably all 4. A GIK soffet trap would work as well, and could be considered.
For the front wall behind the speakers, you'll have about 6 - 6.5 feet of wall left after the tri-traps. I'd put 3 2'x4' panels there which would cover the entire width of the wall. 2" thick panels will work, 4" might be better but more expensive.
Side walls, I'd suggest 2 2'x4' panels per wall, spaced close to each other, and centered on the first reflection point. I'd go with 2" thick panels here.
For the rear wall a diffuser would be the best option I belive. Quality diffusers aren't cheap though, and I'd think you will need about 4'x4' of coverage.
The cheaper panels will work just fine for the most part. Some more expensive panels have things like high frequency membranes, or a wood frame that stands them off from the wall for greater effectiveness. But get whatever fits your budget. You can even make your own for very cheap. I get 4'x8' sheets of rockwool, OC703 equivalent, for about $32 at my local commercial construction supplier ... and Roxul AFB for even cheaper per square foot.
Bottom line is you'll never be happy with that room until you treat it.
To the poster before you, Hew - there's a HUGE difference between a 12'x14' room and a 8.5' square room. I've heard 12x14 rooms sound pretty darn good with no treatments at all, the 8.5 square room however is just about a worst case scenario. Good luck!
In a very small room like that, you need to cover most of your wall space with treatments. Not necessarily floor to ceiling, but 4 foot panels centered height wise with the speakers. In the corners you will need heavy bass trapping, again I'll recommend floor to ceiling GIK tri-traps in at least 2 corners, and preferably all 4. A GIK soffet trap would work as well, and could be considered.
For the front wall behind the speakers, you'll have about 6 - 6.5 feet of wall left after the tri-traps. I'd put 3 2'x4' panels there which would cover the entire width of the wall. 2" thick panels will work, 4" might be better but more expensive.
Side walls, I'd suggest 2 2'x4' panels per wall, spaced close to each other, and centered on the first reflection point. I'd go with 2" thick panels here.
For the rear wall a diffuser would be the best option I belive. Quality diffusers aren't cheap though, and I'd think you will need about 4'x4' of coverage.
The cheaper panels will work just fine for the most part. Some more expensive panels have things like high frequency membranes, or a wood frame that stands them off from the wall for greater effectiveness. But get whatever fits your budget. You can even make your own for very cheap. I get 4'x8' sheets of rockwool, OC703 equivalent, for about $32 at my local commercial construction supplier ... and Roxul AFB for even cheaper per square foot.
Bottom line is you'll never be happy with that room until you treat it.
To the poster before you, Hew - there's a HUGE difference between a 12'x14' room and a 8.5' square room. I've heard 12x14 rooms sound pretty darn good with no treatments at all, the 8.5 square room however is just about a worst case scenario. Good luck!