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
Post removed 

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 !!!!