Micro Studio & Soffit Speakers Question

Hi! After all, probably my english is not the best so take pacience :) I have been working in a veeeeery little studio for 3 or 4 years. As is not possible for me to pay for a bigger place I have to conform with I have, and it's time to make some changes to the room to get a better sound. I can't isolate the room, if I do that only my cat will enter in the room. The first measure I want to apply is mount the speakers a la soffit. My question is: I have to build the structure until the ceiling or I can leave it as in the picture below? As the ceiling is about 340cm I want to make some bass traps behind a false cloth ceiling. When I learn to work with sketchup I will post my final idea. Many thanks

Sorry, there is no measures in that pic. This is the right one

That will be fine. What hard surface are you using as the "baffle" Will it cover most of the soffit?

Thanks for the help :) I think that I will use thin plywwod for the superior part of the soffit and cloth for the inferior. (The soffits of the picture are coppied and pasted from a design of John, and it are finished by this way). Between the soffits I will put a high absorber. To the side walls I will use slat absorbers. To the rear corners more slat absorbers. And below the ceiling, the bass traps. The only problem is that I can use high abosrbers in the rear wall because there is the door. O yes, and another problem is that the house is too old, the walls are not flat (it are plenty of dunes) and all the corners are not 90º, two are like 95º and the other two are OK, so If I mount the soffits with MDF like in the picture I will have a little gap in the side wall, I think that this is not a real problem with the simple design that I will do... Thanks again!

Don't go to thin with the plywood, you don't want it to vibrate.

OK, I understand, I've revised the sketchup file and it's covered with the same wood of the rest of the structure (20mm). Thanks, I'm making the design with sketchup...