Lasher:
Please be careful. Most likely even where you live, the building code will not allow MDF board to be used as part of wall assembly due to its combustibility. You want to use gypsum board but proven assembly that gives required sound insulation. There are many combinations available. I’d suggest getting a professional opinion first even if you do the construction work yourself. You want this to work at first attempt because nothing is more frustrating than having to tear down the wall you’ve just put up and do it over.