Room Treatments - Where to learn more?


Can you suggest some links to websites with practical advice on how to improve the acoustic properties of stereo listening rooms?

I'm about to do a major upgrade to my mediocre system. After reading Robert Harley's "High End Audio" Chapter 4, I gather that room treatment should be near the top of the list for areas to work on.

This is probably especially true since my room has so many hard surfaces.
Picture of my Room
Suggestions on practical ways to improve the sound of my room would be welcome. My thought for the first step is: install drapes on all those windows. The room size is 21 x 22 x 8 feet with 3 open extensions into other spaces.

What else would you suggest for me?
What has worked for you?
hdomke
Tobias suggestions are right on and two of four suggestions I would make.

At The Home Entertainment Show in NYC this year, I noticed that the rooms treated with Real Traps sounded noticeable better than other rooms. I spoke with Ethan Winer, the proprietor of Real Traps, who is very knowledgeable and helpful. I purchased some of his products and they have produced a phenomenal improvement in the sound in my room.

http://www.realtraps.com/

Also, "The Master Handbook of Acoustics," by F. Alton Everest, is the bible.
Acoustics circle

Realtraps, Ethan's articles

Ethan Winer: Acoustics Forum

gik acoustics

What kind of bass trap do I need? BBC/DIY

More DIY

absorption

Some links that I had lying around. There are more forums and DIY sites, but most of the forums have the same crew of experts.

I'm playing with fiberglas/diy panels, I'm treating a bad (tight) space and experimenting so that I can move on to a family space. It's well worth the effort, unfortunately I am finding the ceiling makes a really big difference in beautiful tone. Simple treatment (corners walls and ceiling err... not simple, sorry) will reward you in great bass (the holy grail).

Even my ridiculously simple attempts have yielded great results. I started off unintentionally deadening the area and learned about what worked and what took the energy away.

Otherwise take a look at some of the more respected names, it's worth the money not to have to build, and they do a better job that glued fiberglass and wood

Gregg
There is some basic info here http://www.decware.com/newsite/mainmenu.htm
I used Auralex foam products http://www.auralex.com/in a dedicated room but they may not fit your decor. I wouldn't use them in a living area.