[rollo]

  We have used hollowcore wood doors. Luan for less reflection. baltic birch for more. Used at the front wall from floor to clg. To take it up a notch wood mouldings in a series of squares.
 Absorbtion the ole Persian rug trick hang it on the rear wall and smaller versions at the first reflection points of the side walls.
  If all fails call Brian or Ethan, spend some money and do it right .



charles 

[Roc]

Home Depot, building supplies, roofing/siding panels, 4'x7', painted asphalt, sine wave/corrugated profile,  $20.  Work very well to get started.
Give them a "bow", don't keep flat against wall.

[oboaudio]

Roy is right. For "quick and dirty" take a lesson from some of the shows.  Go to Walmart, Hobby Lobby, Michaels, or wherever and get some artificial (plastic) plants. They won't match commercial treatments but work well, give you flexibility, and can look great!

Paul

This is what I built for diffusing and absorbing bass behind the listening seat.  They are called poly cylindrical diffusers.
I used tempered Masonite that is stretched over curved plywood members.  These devices are filled with fiberglass and
are completely sealed with weather stripping, providing a airtight chamber.   Different sizes were used to provide bass
absorption and helped to redirect high frequencies.   My entire wall behind the listening position was treated this way and
worked very well.    Not the easiest project but cost was low.     

     

[Big Red Machine]

A little work to make your own as I did, but QRDude is very helpful:

http://www.subwoofer-builder.com/qrdude.htm

If you aren't handy, then, well, probably best to purchase for best results.

[Roc]

Big Red,

I also used QRdude (V2.0) to design and build full frequency QRD's (500-20000 hz).
Notice that the back plates are not flat, they are Dado cut to make high freq. diffusion.
Materials $116 per QRD.  Labor 16 hrs each.
A high end table saw was required to cut the high freq. diffusers.

[hum4god]

here is an interesting diffusor project by stigerik on diyaudio , not quick and dirty thou:

http://www.diyaudio.com/forums/multi-way/142015-my-open-baffle-dipole-beyma-tpl-150-a-114.html

[Rclark]

^

That might be the easiest of all though! You don't even need glue,you can just cut,and lay into the pattern. Interesting.

[richidoo]

Stig's wall reminds me of these BBC articles. Worth posting again:

http://www.pmerecords.com/Diffusor.cfm
http://downloads.bbc.co.uk/rd/pubs/reports/1990-15.pdf
http://downloads.bbc.co.uk/rd/pubs/reports/1995-01.pdf