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.

unsound
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?:


https://soundmanagementgroup.com/

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 !!!!