new budget basement studio

hi all. i have been reading here since i purchased my property late last year. time has come to build some walls..... property is a 220sq meter basement (so no windows), the area intended for studio is 6x 9 meter section. there is nothing directly above (except garden) and nothing on any side (except dirt) basically it is a bunker in the city.... ceilings are 9 foot (2.75 meters) construction budget is minimal (say 3000 AU$) plan is for 2 control rooms (myself and a business partner) sharing one live space, and booth. attached is an early/ rough plan (please excuse my drawing skills) i would appreciate any suggestions, re the layout, and construction. thanks in advance.

some more info that i thought might help. the external walls that cannot be changed (west, north and east) are 12mm plaster, fixed on metal studs, to the solid concrete wall (with nothing but dirt on the other side) so i dont see any real problem with sound getting through there, BUT i guess it will be transfered between rooms down those walls. as i say, budget is minimal, so i guess i just have to live with that yes?