Are There Improvements that Can Be Easily and Quickly Made Without Buying More Stuff?

i spent 9 months treating every surface of my listening room through trial and error.

the cost was about $350 worth of cloth and thumbtacks, and about $600 worth of Aural T-fusor diffusers.

these changes were the biggest performance boost i ever experienced. this was after living in my purpose built room for 10 years somewhat frustrated i could not get things to sound better. since i did this in 2016 i have been completely satisfied with my room and system.

you can see pictures of my room in my details.

in the context of my room and system it was couch change.

@mikelavigne 

Wow!  I did look at pictures of your room.  I appreciate your advice!  And I will follow up on it.

You have a really beautiful house. Looks like a wonderful view.

I don’t think you need to know what is wrong… or what your objective is. By trial and error you can find out what it’s capable of. As soon I have optimized all wires (which of course is an expense)… then I go after the venue.
 

The answer to your question: all the things you say you cannot change (in your system description). Placement, floor and wall treatments. These can make large differences.

Is moving your system to a dedicated / or at least acoustically better room a possibility? That much glass and open flooring are the first thing I would go after. You can see my system and see what I did was incrementally work on these things.

start w the Jim Smith book mentioned above…it has many…. free…ideas 

I would say go through the virtual systems of other members and get ideas about room setup and placement. The other thing is to look at the recommended dolby placement guidelines for your setup re: the angles and dial those in exactly as you can. The other thing is all of the glass, can you get curtains?