I used GIK. Very good people to work with. I have a 12 by 21 room. Cost about 1200.. they are 6 to 8 inches thick. I could buy more bass traps but haven’t put up on my list. I can walk around the room and the music sounds good with only a little bass peak in a corner.There are many things that come to play., sub placement and speaker placement are two items that need to be dealt with.
Recently, I put speakers and subs on springs. This helped as much as the room treatments. It is much easier when it is a dedicated room.