acoustic vertical window blinds

Does anyone have  recommendations for manufacturers or suppliers of room blackening/darkening vertical window blinds for use in my mostly audio room? On each equal length side of each speaker ( a bit over 6' ) there are windows, on one side a standard double hung, on the other a rather large 4 panel bow window (over looking a fairly lovely private natural setting). I may or may not stay in this house for very long, so I neither want to overinvest nor shortchange my listening pleasure. I need to replace the current vertical blinds, and thought my fellow Audiogoner's might have some suitable suggestions.

Thanks in advance.

I have three windows behind my speakers and a patio door on the opposing wall. Last year I installed Hunter-Douglas Cadence Vertical blinds and I used to have acoustic panels on the walls and have not put them back up. These blinds when you look at each vane From the end have a S shape to them. They are fabric but very stiff to retain that shape. You may want to look at those they show them on the Hunter Douglas website.
have you checked lowes or home depot  ?
One solution that will work better than any blinds or shades is to attach a number of ASC or GIK absorber/diffusers (like the ASC sound planks) using Velcro tape. This will be fully removable when you leave and you can also take it with you. Finally adding a Marigo VTS window dot to the glass will also help
@folkfreak What do the Marigo VTS window dots do? Do they absorb the sound vibration on the glass?
My listening room has windows behind the speakers and also along one long wall. After trying absorbers and diffusers, I finally got a great sounding room using the Synergistic Research HFT products. They are easily removable and so can be removed and taken to the next house when the time comes. Also they are not visually distracting.

David Pritchard
Re Marigo VTS Dots: Marigo Dots come in various sizes depending on application - from capacitors to circuit boards to electron tubes to speaker cabinets to walls to windows. The dots operate via constrained layer damping. To whit,

”Beginning in the early 1930s a variety of theoretical and experimental research has been published regarding the development and use of damping. What began as an experiment to reduce noise and vibration in metals and plastics has become a common treatment in an amalgam of applications. Constrained-layer damping (CLD) is a specific method of treatment commonly used in the aerospace and military industries. CLD may be described as a type of shear-related energy dissipation achieved by interconnecting two or more structural materials using a relatively thin viscoelastic layer. Among the advantages of using CLD as a damping treatment are the ability to obtain high loss factors with relatively thin configurations and that the stiffness of the composite system is not markedly increased.”

Adding to Geoff’s description the window dots, which are actually quite large being about 2” across and 1/4” thick, when correctly placed help damp resonances in the panels of windows.

I also have HFTs (and SR ART resonators) on my window as well. Each of these tools serves a different purpose
1. The marigo dots damp the glass and make it more like a wall
2. The sound planks treat reflections from the glass/wall
3. The HFTs then focus the sound at the reflection points and make the glass/wall disappear

The good thing is all three are readily removable

ps my window is also an acoustically designed dual double pane setup without any parallel surfaces ...
OK. Thanks guys. This is very useful information. I won't try them in our current house as there is simply too much glass to treat. But our new house which is in the building stage, I can plan to incorporate similar tech for it. Cheers. A.
You might wanted to consider the current available vertical blinds from Blinds on The Net. I believed the Balmoral Textured Block Out Vertical Blinds is the one you are looking for.

Just an addendum to say there are a couple issues with glass doors and windows. There’s the fairly obvious vibration issue which, like room walls, can be dealt with a number of ways. But there’s also the RFI issue that might be less obvious. I suspect tiny little bowls will help with RF, although that’s not obvious. Maybe other things, too...Plus one can try to protect electronics from RF once you’ve allowed it into the room through the windows. Not to mention reflected acoustic waves.
You might also consider pleated shades. They aren't very expensive and they cover the glass vey well. I use them. and the pleats as well as the soft material is good for absorbing sound. 
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Thank you all for your considerations:

has anyone tried anything like these?:

You can buy blackout electric blinds for example
Hunter Douglas = good
but I learning something from @geoffkait and @folkfreak and will get some when I replenish my supply of microdot
seriously I have a 12’ window in my high end room - cantilever out over Puget Sound, so the view ain’t going away....

thanks for the cool cool and informative post !!!!
Hunter Douglas fabric verticals sound wonderful in my listening room.