Duke, Cats and Curtain Liners

I know it's kind of a random mix but here goes.

I've noticed that my cats spend more time with me if I'm playing Duke Ellington.  While trying out an experiment with the Duke and the cats I also put up new blackout curtain liners to help reduce the amount of heat that makes it into my living room and, surprise surprise, they are actually helping improve the imaging of the speakers in the vertical plane.  I say I'm surprised because I thought just my normal curtains were enough.  They are thick linen curtains which let in too much light and heat until now.