What are the best Room Accustic Treaments members have found?


I  am looking into adding some room acoustic treatments to my room.  I am just looking for advice on some simple room treatments that fellow members found worthy of purchase. 
128x128davidrolson
One of my favorite GIK products is the soffit traps. In particular, for corner traps, really wide coverage in small footprint, and for an apartment dweller, easy to stack a pair in each corner.


If you are attempting deep bass, or have 2 way speakers you want to make sound bigger, highly recommend them.
Asc is the company I have used . They don’t charge you anything upfront for their recommendations. They even sent me equipment, free of charge, to record tones played back through my sound system, recorded from my listening chair so that they could assess articulation and the problem frequencies that needed taming. They then sent me blue prints on what they recommend to be done in phases, based on videos , pics of my room and the results from the above sound recordings.
Jordan  is the sound engineer i work with and he bounces all ideas through Art. They are always available to answer your questions and they were and still are a pleasure to work with.
Books, shelves, art & carpets.

But then, I spent a few decades in sound studios, so I'm probably odd man out here.
To trail onto this thread, does anyone know of room/wall treatments that are not a few inches thick? Is there such a thing?

Due to the room, anything thick sticks like a sore thumb. Thinner that can be painted would be a jackpot.

I apologize davidrolson, I do not mean to hijack the thread.
GIK service and products are very good and competitive.  Keep in mind, they carry NO inventory; everything is made to order.  It’s how they keep their prices down.  My salesman told me today, an order placed today would deliver 2nd week of January, at best.

The suggestion to read up on the subject is a good idea.  GIK has some good You Tube videos.  So does Acoustic Geometry but they’re very expensive.  Lastly, GIK list their suggestions in the order of importance.  If you have the patience, purchase one solution at a time.  I think you will make more cost effective decisions (if you can be patient).

Best investment you can make to maximize your investment.

Cheers