I use some ACDA panels from Acoustic Fields and some diy stuff)....The ACDA panels are an eye/ear opener if it is in your budget, Fair warning: it is a lot more expensive than GIK, ATS, etc.
Room Treatment suppliers
I know about GIK and ATS. I stumbled across another supplier on here that had some really well done art panel and diffusers but can't remember who it was. What are some of the other supplier besides aforementioned?