The Rooms can also be evaluated on the Amount of Apertures and Aperture Dimensions.
Doors and Windows on External Walls and Internal Walls will have a strong influence on the balance of End Sound.
A Hollow Door used on the Room Entrance will most likely create a Reflected Colouration to the Sound being Produced.
It has been known for a inner panel to be produced and attached to the Internal Face of the door, where a Cavity of approx' 20mm is filled with a highly compressed fibre insulation or Koln Dried Sand. When a door is given this type of treatment there are usually additional seals used to prevent air movement between door and Door Fame and Door and Threshold.
Depending on age of Widows Air Movement might need to be controlled with a Clear Tape typically used for Winter Periods as an Air Seal on Leaky Windows.
Controlling reflections of the Glass is more complicated, but a Heavily Lined Curtain is the cheap option with limited effect. Padding the Curtain with a Fibre will help furthering the curtains function for controlling reflective sound.
https://perfectacoustic.co.uk/product-category/acoustic-curtains/
The Room is the Room, the Room will be much better as a Space to manage Sound being produced, when measures are adopted, to make sure the End Sound created by the Audio System is only heard once by the listener.
When the End Sound produced within a particular space is coming from Speakers that are adequately coupled to the space, the notion of being in a particular sized room of a particular ratio will quickly move on.
The Bliss being experienced, the sense that Sound is not adulterated and not coloured is to Supersede all other notions.