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
From my reading, acoustic experts state that the listener needs to be a minimum distance from diffusers for them to work correctly. Any less than that distance is not advised, absorption is recommended instead. So what is that distance? I'm not positive, but I believe it is in the neighborhood of 5-6 feet. I may be mistaken.

I have to sit very close to the rear wall, so made a 4' X 4', 6" deep frame into which I installed a 6-pack of Owens Corning 703 (each 2' X 4' X 2"). Works pretty good, and in any event will have to suffice until and if I ever have a larger room, which appears at this point unlikely.
Synco de- I made 12  2' x 4' fabric wrapped panels using 1 x 3 cheap wood with inlaid corner bracing on the back. I I could ever figure how to post pictures of my system on this site I would show you.

Bottom line I was about $300 all in for wood, 703, fabric and stapler.
(buy/borrow a pneumatic) Sold six at $25 each and kept the other
6. My cost into the ones I kept was $150. Can beat that. 




Lined drapes on the windows and a large fiber art piece behind the listening position will help. Both can enhance the living room feel and fiber art piece, large handmade rug or handmade quilt can be an investment as well. If a TV is involved, a quilted cover for that will work wonders.

Good luck.
Change the wood blinds to heavy drapes and you do not mention the floor but that can have a detrimental effect on the sound especially if it is hardwood, ceramic, or some other hard surface. If it is a hard surface floor try a heavy area rug in front of the speakers. With just these small tweaks you will have a much better sounding room.
I have been at this in my room for 7 months. I started off just trying things here and there and listening. The number of places to put things seemed infinite. I had blankets and towels everywhere, bought some panels, moved them around. It was time consuming and crazy making. Then I took some advice I had been resisting -- buy a $100 mic and download REW, Room EQ Wizard. Learn the basics. Measure, treat, listen. Repeat. Learn where your room’s reflection points, peaks, and nulls are -- for real. In some cases, theoretical predictions were correct, in other cases, they were way off -- because I have an odd room.

I bought OC 703 panels and wrapped them in fabric. With 6 of them I made two 2" panels and 2 4" panels (doubled up in side a fabric pillowcase). These proved to be very effective tools to test out various effects in the room, especially when doubling them up and leaving space between them and a wall. They were excellent preliminaries -- in conjunction with REW and listening -- and gave me confidence about how much treatment to invest in later. Throwing money at the room acoustic problem is more wasteful than throwing it at gear because it's much harder to recoup by selling. And it's hard to integrate into an existing domestic arrangement.

Set some goals, get the right tools, work patiently and incrementally. My two cents.