Are projector screens transparent to sound?

Ok. So i geuss i just put wall treatments to the side of the screen. Are most people using absorption or diffusion on the front wall?

Unless you have a retractable screen and intend to use the panels for music only then yes it is worth a look at, but as said if your screen is to remain down then no use in treatment the sound wont reach.

If you want acoustically transparent screens, then you would have to consider:
http://www.stewartfilmscreen.com/micropx2.htm

Another company that makes acoustically transparent screens is Screen Research. Their web address is below.

http://www.screenresearch.com/

Are these "better" than reflective screens? Do they have the same picture quality?