Window Treatments to Remove reflected sound

I have a listening room with hard wood floors, two French doors beside one speaker, two more across the room and two walls full of windows. Any thoughts on the best window treatment to improve sound? I'm assuming metal blinds are just as bad as the glass and am considering cellular blinds, which seem to be made of polysester but have an air pocket in the middle. Any experience on what works best? Thanks for the input
Wood slated blinds work better than metal but are very expensive. Fabric blinds/carpets/curtains - heavier the better.
I have what you are referring to as "celluar" blinds behind my listening position. (It covers a large bay window, and two smaller windows, at the side angle points, behind the couch.) BTW, I refer to them as "black-out" blinds, since that is why they have the "air pocket" that you mentioned. It keeps the light from coming in and messing up the picture on the RPTV on the wall opposite of the bay window.

They seem to work very well, IMHO, as it disperses the sound pretty well, and I don't get much in the way of sound reflections from the rear.
(Whether this is the perfect solution, from an accoustical standpoint, I am not sure. But since it does not add rear sound reflections to mess up the imaging and soundstaging from the direct sound coming from the speakers, I am okay with it.)

Perfect? Probably not, but since I am constrained by the old WAF, I don't really have a choice.

My two cents worth anyway.

Good Luck!
Your best bet if not using specific room tuning devices would be draperies with 'blackout' linings.
Double or Triple Honeycomb cellular shades work well too.
If you get curtains, err on the "too much fabric" side. The more folds the better.

I have a related question. Anyone know how to treat "ringing" of large pane windows. I've got a 48"x56" double pane that rings, becomes excited at various voice frequencies. Man, they don't make windows like they used to (thin glass for double panes).
Fabric of any sort is better than anything else. Long, too, like to the floor.
Pleated fabric blinds work well.
Marigo window tuning "dots". check for these at
It's hard to tell what the Marigo dots are made of, but for substantially less than $79, I'd suggest experimenting with several sizes of felt chair feet and flat rubber "bumpers" available for about $3.00/sheet at Home Depot and other hardware stores.

BTW, I can see how these would work. Kind of like felt dampers used on drum heads.
This is not necessarily the "best" accoustic solution, but it does have some advantages. Behind the listening position in my rental apartment is a standard two-panel sliding glass door that leads to a balcony. The landlord furnishes apartment-grade, hard plastic vertical blinds, each blind being about 4" wide. I simply set the blinds at a 45 degree angle to the room. In theory, sound waves hitting the slanted blinds will reflect at various angles, depending upon the angle of attack. A few will bounce back into the room, but most will reflect into adjoining blinds or to the glass behind and then reflect into the back side of the other blinds.

Does it work? Aside from the sliding glass doors, my room leans toward the bright side, but I don't experience any noticeable listener fatigue, muddy textures, compressed soundstage or confused imaging.

One advantage of slanting blinds, as opposed to draperies or shades, is that you don't have to banish sunlight during daytime listening. Of course, slanted blinds will work even better when they are made of wood or are covered with fabric. And if outside noise is also a concern, thick draperies or black-out shades would be preferable.
No set blinds will have any effect below mid-frequencies and exactly where they will change from dispersing the audio to reflecting it is somewhat unpredictable. The glass is transparent to bass and reflective of HF so, in order to have a nearly equal effect across the spectrum, you need some heavy absorbtion from the low midrange up. I've used velvet drapes interlined with dacron acoustic batting. Since the coverage is adjustable, you can titrate the effect you want.

Thanks for the good input. What exactly do tuning dots do? There is no explanation of them on the web sit referenced.
Tuning dots, if they work like drum head dampers, reduce vibration and ring. Sort of like when you lightly touch a ringing wine glass. Depending on how softly or firmly you touch the glass, the ringing will be reduced or eliminated.

At least that's how I believe the tuning dots...or felt/rubber furniture protectors...would work.
A previous room had three large windows that were covered with "cellular blinds" and then the windows had heavy fabric over treatments. This proved to be very effective. You could even discern differences that resulted from opening the blinds differing amounts.
I agree with Dougmc. I have plastic 3 in. regular shutters on all windows. Turned at 45 deg., they provide good mid/high diffusion and light control to boot! Wood might work even better. (Lets, see... maple? (:-))