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

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.

Hilde45 - I have read several of your posts regarding your journey to manipulate your room's acoustics and they were a good source of motivation. Our reasoning and approach to improving acoustics seem to run parallel, including cost and resistance to use EQ technology (for now anyway) . Although I believe I have the added challenge of storage and convenient repeatable implementation.....uhhhhg:) 

Anyway I pulled the trigger on 12 panels of 703 and other materials, it's about $275 all in. So If it doesn't work....well, it's wouldn't be a big financial hit. Plus I have a consumer HT system in another room that SQ would definitely benefit from, and it would be easier to implemented without the added hurdle of portability and aesthetic restraints.

Speakermaster; 53B - unfortunately the addition of rugs and drapes aren't an option. But a quilted throw is an option.Thanks

By the way, if all goes well I plan to post images of room with panels implemented vs stored in "my virtual room". 

Thanks again