How to attach a box to the wall

[trasker]

I am going to build a soundproof box to place over the fan unit of our mechanically ventilated floor to reduce the noise a bit.

The fan is mounted on a concrete wall, partially below and partially above ground.

I plan to build the box out of MDF and insulate it on the inside.

What's the best way to attach it to the wall? I could mount two hooks in the concrete wall and two loops in the box, but that seemed a bit too simple

 

[etompau]

Search for "vinkeljärn," there are a plethora of different sheet metal pieces with holes that might fit.

 

[Isakare]

I would have come up with some brackets on the top and bottom of the box/wall that slopes upwards. When the box is hooked on, gravity helps press it against the wall.