Acoustics Tips for my Controlroom

Hi My room is Lenght 455cm, Width 341cm, Height 276cm (in the middle off the rom) Left hight is 288cm and the right side height 267cm any suggestion how to acoustic treat this room. My door is on the lenght wall in the corner and i have one window. Have thought about to build one small "box" for vocal/speaking recording down in the left corner, can i do that or is the room to small. Thanks for any tips Dennis

Dennis - could you try something like this?? cheers john

Yes and thanks, this one look nice!! But i forgot to mention the air-condition pipe in the ceiling/wall (sorry). But if i build like this how about the acoustis? I mean the rear wall would be very close and i get one window on my right side. Thanks Dennis

Update for the image Dennis