On the rafters introducing unwanted reflections...I would imagine some sprayed in insulation would help a lot with that. If this a 'home theater' area or just a listening room, using a rattle can or two of flat black paint on the applied insulation would make the look uniform and avoid reflections from the Video display in the room. Lets think of good ways to do a nice listening environment on the cheap. Once the tariffs have their way with us, and the IRS has their way with us, and inflation has its way with us, figuring out ways to pursue this expensive addictive hobby with clever low cost improvements is going to be key to moving forward.