Mani+ Marty have pretty much nailed it.
I'd only add listen first before adding treatments. They are easy to add and may or may not be needed.
Also I find any wall adornments/decorations, including even block style picture frames with an inch or so of depth to help break up large parallel surfaces usually only helps.
Then of course room furnishings applied in the end like chairs or sofas and other decorative items that lack hard reflective surfaces can be used to help dampen the room acoustically (similar to how internals of speaker enclosures are dampened with sound absorbent material) if needed to provide some final tweaks to whatever extent needed.
Also thin but dense carpet over the concrete foundation works best from what I have personally experienced over the years in many rooms and houses.
USe your imagination to find things you like and want in your room that serve a purpose and also might help with the sound. Most room furnishings that can help a room sound good is not marketed to audiophiles and sound engineers!
You are a lucky guy! Having/building a room that works good for audio is a huge advantage that can elude many music lovers!
I'd only add listen first before adding treatments. They are easy to add and may or may not be needed.
Also I find any wall adornments/decorations, including even block style picture frames with an inch or so of depth to help break up large parallel surfaces usually only helps.
Then of course room furnishings applied in the end like chairs or sofas and other decorative items that lack hard reflective surfaces can be used to help dampen the room acoustically (similar to how internals of speaker enclosures are dampened with sound absorbent material) if needed to provide some final tweaks to whatever extent needed.
Also thin but dense carpet over the concrete foundation works best from what I have personally experienced over the years in many rooms and houses.
USe your imagination to find things you like and want in your room that serve a purpose and also might help with the sound. Most room furnishings that can help a room sound good is not marketed to audiophiles and sound engineers!
You are a lucky guy! Having/building a room that works good for audio is a huge advantage that can elude many music lovers!