I can see this space being an acoustical nightmare. Before adding permanent or retractable walls I would suggest you consider:

1. Adding a rug to the dining area.

2. Cladding the entry arch with wood.

3. Putting acoustic panels in back of your paintings.

4. Hanging more artwork and adding some potted plants.

I see 2 straight/horizontal ceilings at your entry - what if one of those were designed to be a secure wall of part glass. Dining is different with its chandelier and I wonder if that could become more secluded? People walking in wouldn't have immediate views of it. Already living rug, and was suggested adding more, but it might be too many for also a foyer rug!

* Install acoustic tiles on your flat ceilings. They will absorb some of the sound waves;

* Hang larger paintings, tapestries or drapes on your walls (or columns);

* Use larger area rugs and a rug in your dining room.

* Fabric wall panels will also muffle sound.

Upper East Side · More Info

24"x24" White Decorative Ceiling Tiles, San Diego Design, Set of 8 · More Info

FPB's fabric panels could be great, drawn or not....probably better brought back with ties/ropes?

Thanks Everyone! Great ideas - and I agree with the rug suggestions as well.

Trying to find some pictures of what this might look like @felix-pradas ! Curtains AT the pillars? Or Curtains between the pillars?

Also - I had thought about putting in a wall to the left and right of the door/entry area (where the wall would be straight from the front door wall to the next pillar - lining the tile area). The openings would be where the archways are currently located for both the dining and formal sitting areas. Thoughts?

Just a quick rendering if you decided to put up walls. ( Click picture to enlarge )

isnt it awful, how you buy a perfectly wonderful house and suddenly one night someone comes and steals the interior walls?

consult an architect, it might not be so hard to replace at least some of the walls that are missing.

Another thought is a coffer ceiling in the dining area - perhaps even the formal sitting area. The more you add the less the sound can travel, echo and resound.

This is an example of a barrel vault arch (wood clad)

Is this your furniture or the previous owner's? I'd get rid of the red fireplace accent wall. You can add screens in strategic places to give some definition to your space.

Fabric covered screens and wall hangings can help dampen reverb.

Heavier drapes at the windows would help, along with the previously suggested rugs.The heavier drapes will stop some of the reverb coming from the windows.

Is this your home as it is presently? It is gorgeous. I would keep the red accent on the fireplace, otherwise you could end up with too much of the same from room to room.

You could consider buildings walls and creating a foyer or a long hallway to section off the rooms on either side. This would give your home time to transition from entering into dining and entertaining.