Spent half the day gathering together some of my crude, out of date measuring equipment to better determine (or possibly confuse me even more) the band of frequencies I need to control, including some contact microphones (acoustic instrument pick ups, although not calibrated for any kinf of scientific measuerments, they are very sensitive) I actually attached to the glass.
My research on our windows tells me they are not really glass, but a triple pane affair made of poly-some crappy long name plastic compound designed with aluminium in the panes, mainly to block heat transferrence. That felt really positive knowing that we have really awesome, modern windows throughout this house. The poly-messy-named "glass" still makes a boom at around 800 to 1200 hertz resonance when you just tap on them.
That's an area of concern if the memory of having pitch imperfect ears and still instantly knowing how to find a problem frequency band on the EQ (from my sound reinforcement days) has any bearing, at this late date in my ''Hearing Career."
The actual hard surface reflections are still to be determined exactly, but the testing with frequency generator has only begun. I have a long way to go.
My wife just shakes her head and asks why I can't just enjoy My New Room. My explanation of how this is a part of my enjoyment just frustrates her more.

One thing I haven't talked about is that we have these high grade/high dollar blinds over all the windows in the house, which help quite a bit. They are painted solid wood slats two inches deep and about 3/16 inch thick. I am still hoping that there is a magic angle where the blinds take me part way to where I need to be. Only been listening in this room for three weeks now.
One thing I do not want to develop is an acoustic numbness that lowers my sensitivity to the point where I just get used to it all and don't try to help what needs help.
I have a challenge!! But it is MY challenge. I have work to do.
Any ideas from any amaruer acousticians would be welcome.