Question Where do I place these acoustic sound panels?

[83y]

I have 24 sound panels, each being 2inches thick and 30x30cm, my goal is to reduce noise when I am talking for the neighbors above, I am thinking of placing the panels on the ceiling, but I am not sure where the best placement would be.

My plan is to have around 19-20 sound proof panels, where the 8 panels is in the first photo to give you an idea of the space it is, and repeat it 3 times so its roughly 24, but I might not completely fill it as I want to put a foam panel in all corners of the room as I have heard this reduces the noise.

I am not sure whether to start placing the foam panels after all the products on the shelf or straight from the back of the wall because I am not sure if all those products there will already act as a sound barrier or not.

PS: I will mostly be talking from my setup / desk.

Images

 

[geofelt]

You are a good neighbor.

I think I might start the panels on the red line you drew and not above the shelf.
Sounds from you are likely to be deflected by the shelf.