Diffuser or absorber behind listening position....and is it worth doing??


I am a relatively new to serious two channel listening so I don't have a lot of experience to rely on. However, from what I have read on this site I do feel pretty confident that improving my room acoustics via absorber and defusers panels will be the best way to improve SQ at this point. Unfortunately, because my listening room doubles as my living room the only place I can only use panels ( no base traps) and only behind my listening position.... hence my title question. What say you.....will I benefit from adding diffusers? Or should it be absorbers? or forget it and be happy with what I have. (which I am.... )

Here are some room and placement specifics:
Room 12 ft by 18ft 
Speakers (ribbon tweeter) on Long wall with large window with wood blinds on right and drywall on the left
Speakers baffle are 32 inches off front wall and 48 inches off both side wall and are 10 ft apart with a 6x9 rug.
Sitting position can be either against the wall or 2ft off the wall (just slide couch forward....which I do because sound stage and imaging is better).

My main goal is to improve imaging and stage. If it is worth doing, would there be any other benefits? Also,
could you recommend how large a space should the panels cover..... how thick panels should be?

Thanks in advance



 
mrpsync
Bob- thanks for the compliment;  my fireplace is gas as well and enjoy it for the same reasons. 

You are correct that the wall and openings angles behind the speakers are different (though not as much as the Pano image suggests). With that said the baffle plane of the speakers intersects with the walls/blinds and not the opening....so I suspected it's  mostly low frequency from the speakers (rear ported) that is lost into the openings. But that is only my speculation,  you're probably right and will experiment with room dividers. Thanks you

Oh, and I appreciate the vote of confidence with Tomic601. I've read his posts in the past and concur.

Tomic601

It's reassuring the opening in the room are conducive to eliminating room nodes (one less thing to worry about). Sometimes I only hear issues after reading they exist on this forum.... It can be a curse :)

I like the idea of using lightweight diffuser panel over the TV, once the absorber is behind the couch. And I'll check out studio six and try to get familiar with it.

Also, if I may, does the information I provided to Bob regarding speaker plane and angles help with asymmetrical reflection quandry? or is my speculation misguided?

Thanks
If all you can do is the wall behind you then do that.

If the wall behind you is close, like immediately behind your listening position go with 100% absorption and as much as you can.

If it’s 6’ or more away, a mix of absorption and diffusion.

Another thing to do is consider speakers with more controlled dispersion. Klipsch Heresy’s for instance, line or ESLs are going to be better for you, as would open baffle.

If you can do the left wall, along with thick curtains on the right then do that too.

Keep in mind a lot of room treatment looks really good now, GIK art panels for instance let you pick any art at all. 
Area high-shag rugs are very useful. Home Depot DIY insulation fiberglass with foam wall panels work well behind the speakers and side walls help dampen brightness. Acoustic foam or pillows near your ear-level and ceilings are a plus. Additional foam behind your listening chair rounds-off the bounce-back. 
Don't be flummoxed into falling into a hole of improvements. GIK acoustics do picture panels so you can combine art with diffusers / absorbers. I have 3 art absorbers back wall with 2 corner tritraps. I have 2 diffusers on stands I move into place for serious music time for the side walls. I also have 2 thick pile rugs on top of each other in centre of room.

These all help.... I then went further and placed speakers on isoacoustics feet(massive differance but £500) and got a good mains stabiliser.