material for curtains? best absorbers?

My listening room is on the bright side of things and I'm going to add curtains over the current sheers. I want to know if any particular material or weight of fabric are better for the purposed of absorbing sound and hopefully taking the edge off of the brightness in my room?

thanks in advance
If you are not covering windows I would suggest hanging wool area rugs instead of curtains.
You can get a lot of reflection from glass, especially large picture windows. I have Pottery Barn curtains over mine and it is a noticeable improvement when listening at night with curtains closed. I would expect the denser, more tightly woven, and thicker materials would be best for having higher absorption.
Go to klone-audio for information and pictures that you may find interesting. I built some panels for my room and they improved the acoustics in my room tremendously. Good luck!