Reddit mentions: The best window treatment sets

That's my thought, but I'm not sure the best way to accomplish it, whether it's to use a double curtain rod and something like the absolute zero curtains, or to go with a curtain liner like This, or just mount a second curtain behind the decorative one on the same road (the issue being that it's a grommet curtain so I'd probably have to go through a high end store to get a velvet grommet blackout curtain (most are rod pocket, which wouldn't work on the same rod).

I know a few guys in here have probably found a solution for a similar situation.

these are what I bought. The material works really well and it has a backing layer really stops the light

the only downside to these is there is no magnets or anything so they aren't sealed perfect, not to say that you can't finagle it. also, they kinda look cheap, but I imagine most blackout curtains do under a certain dollar amount

but I ended up getting some of these magnets although they are silver colored and about the size of a half dollar, so your girl friend might object

they def aren't something you want to be opening and closing a lot

the longer your curtains past your window the better, sides and bottom

This one.

We have a really wide window, so these worked well. They are pretty heavy, but are a nice, silky material.

If you don't want to keep the (very likely expensive, custom) blinds, basic lock seam rods (the flat white kind) could probably be mounted in the recessed area where the blinds are currently. If you want to keep the light filtering blinds intact, you'll need to put drapery hardware on the ceiling. There are several types of decorative brackets (like these https://www.amazon.com/Umbra-Ceiling-Bracket-Drapery-Nickel/dp/B00FB6R8HQ?th=1) or, since you want blackout, track that wouldn't leave a gap at the top (https://www.amazon.com/Ceiling-Curtain-Wheeled-Carriers-4-Silver/dp/B01L6C2QQG). Flexible track is also a thing, which would work well with your wall angle.

Would something like this work as an acoustic drape?

Absolute Zero 11718050X084BK Velvet Blackout Home Theater 50-Inch by 84-Inch Single Curtain Panel, Black https://www.amazon.com/dp/B008FPMUIM?ref=yo_pop_ma_swf

You can buy noise-reducing curtains, such as [these] (http://www.amazon.com/gp/product/B008FPMWHG/ref=s9_dcbhz_bw_d0_g201_i1_bs)

curtain hook. they also make 3/4 finger types for pleated curtains