The worse the room, the greater the advantages of the Swarm. Do that first, then wait and see. Odds are you won't need any bass traps.
As for panels, find a local hardware store that will sell you a couple sheets of Owens Corning 703 insulating panels. They're what GIK and everyone else wraps inside their fancy acoustic panels. In raw form the panels are ugly yellow but very light weight and dirt cheap making them a perfect way to experiment and determine what (if anything) you need, and where.
Diffusion panels are a little more involved. But remember, everything in the room is either reflecting (diffusing) or absorbing. You could hang framed art on the wall, tilt it down slightly, you got a diffuser.
As for panels, find a local hardware store that will sell you a couple sheets of Owens Corning 703 insulating panels. They're what GIK and everyone else wraps inside their fancy acoustic panels. In raw form the panels are ugly yellow but very light weight and dirt cheap making them a perfect way to experiment and determine what (if anything) you need, and where.
Diffusion panels are a little more involved. But remember, everything in the room is either reflecting (diffusing) or absorbing. You could hang framed art on the wall, tilt it down slightly, you got a diffuser.