Acoustic Damping Behind Speakers?


My speakers are placed about 3.5 feet from the wall behind them, which is just drywall. I get a funny echo from the wall and have been using the cushions from the sofa as dampers, which actually work fairly well. I can't imagine why, but my wife does not think this is an ideal solution, so I'm looking into some sound deadening options.

I was looking at Acoustimac panels, which are reasonable at about $50 each. Does anyone have any other favorite - and reasonably priced - products?

Also, at this point I'm only contemplating using two, placed directly behind the speakers. It would be difficult to get any more past 'she who must be obeyed'. Would this be sufficient? The room has a lot of stuffed furniture in it.

Thanks!
grimace
In 1979 we had the entire wall covered in cardboard eggcrates behind the double Advents. I don't know if it really sounded better or not but people knew we were serious when they walked in. We were blowin' our brains out to Supertramp and Michael Jackson.
Yes, must be tried. I have the Furutech acoustical free standing panels. They work well. Also, putting round units in the front corners should be tried. The latter can be found in most exercise equipment stores and cost less then $25 for a three foot log.
I use these products in my dedicated audio room in North Carolina.

http://www.acousticsfirst.com/

They are very nice to deal with and the products look and work great. I was initially going to use Room Tunes or GIK tuning materials, but liked that Acoustics First did custom color at reasonable prices. The items were very easy to install, and look and sound great. It's nice that the wife likes the look of the product in her house too.....

I came across them by accident, but am glad I found them. Reasonable cost and nice folks too!!!
Fiberglass acoustic panels are readily available in most metro areas in 2'x4' panels, 2",3" & 4" thick. The 4" are under $20/sheet here. They can be covered by any cloth you desire...
The Acousticmac panels work very well for me. I use to bass versions behind the speakers and two "midrange", light thinner panels for side reflections. They also appear to be a bargain compared with others I have seen. I recommend them.