Soffit mounting/bass traps

Is it possible to use the soffitmounts as bass traps. I mean there´s 50 cm of empty space there except where the speakers are. My control room isn´t exacly big 4,3 x 3,1 x 2,6 (height) m after treatment and I have little room for basstraps anywhere else. Another question is when you use the Helmholz calculator which wall is the one you use for calculating. The one with the treatment or the one behind it. I mean if you have a resonator that looks like a wall so is it the distance to the resonator or the distance to the plasterboardwall behind it. I have included a Smartdraw drawing of the place. PS the blue is the airgap between the walls, mostly made for myself to make sure I didn´t overlook anything.

If you check out this cross section of a soffit mount you can see that the area under the speaker is used as a bass trap. Regarding the Helmholtz resonator - the calculator specifies what dimensions to use. The depth is the distance from the slats to the wall behind them. hope this helps cheers john

Thank you very much for that drawing, I have a couple of questions. The plywood, are there holes in it or anything like slats or is it just plain wood. Another one, the timber finish in the top what do you mean by that. Is there a way to calulate which frequencies is likely to be in the room based on its measures. My controlroom is pretty much like you suggested 3 months ago but it´s not a room that can be measured easily with the non-paralel walls and all.

I'm sorry to keep going here but the "wood" attached to the bass hanger, what is that and how do you make it stick to the insulation.

The timber finish is just for looks. YOu could add a nother layer of plywood or MDF but a timber or timber veneer finish will look nicer. The plywood also separates the two boxes - the upper that holds the speaker and the lower the trap area. The hangers are made from celotex (soft fiberboard) wrapped in insulation and hung by wire or string. cheers john

Could that material be something like masonite (or anything cheap) instead. Celotex is not used in Denmark anymore, due to cancer risks I think. So the front of the soffit mounts are just plain wood without any slats, slots, holes or anything, right (except for the big one at the bottom). I have looked at the pictures in your homepage (it's an incredible source of info) and that's what it looks like on most of the pictures.