I have a square room with a peak ceiling and struggled with bass issues. If I walked to the corners it was boomy and at the sitting position there was almost no bass.
I bought 16 Real Traps and placed them every place there was a wall to wall corner, a wall to ceiling corner, and along the ceiling peak per Ethan's instructions. There was an improved bass response and the mids also improved. However, I knew that the speakers still weren't sounding their best. I took the Real Traps out of the corners and used them at the first reflection points and put ASC 20" traps in the front corners with 16" traps on top. And, 16" traps in the rear corners. The bass tightened up and the mids improved even more. I then replaced the Real Traps that were in the first reflection point with RPG wood diffusers. I took the Real Traps and spaced them along the front wall. The room is so changed for the better that my wife thought that I had bought new speakers.
I don't know if every room would have such a dramatic improvement but, in my case the money I speant on tuning the room made a bigger difference than any other component I could have changed.