Hi Sadly my first post is nothing to do with AV but I think you can help I have been commissioned by a good friend to build a large sound proof room for a large piece of industrial machinery, If I get it right I might be able to afford to sort out my current music systems short comings (more about that later). This box is 4mx4mx12m so basically a small house! the aim is to drastically reduce the noise that spills out into the rest of the work space. The current plan from inside to out is sound block plasterboard on resilient bar this is fixed to a 140mm deep timber frame with 100mm acoustic mineral wool fitted between the frames. This is then sheathed in OSB board. I have started construction, the frames are 140mm timber and this is covered in OSB board (from what I have read on hear today this would have been better in MDF) but the infill and internal wall are still not finalized so all ideas would be welcomed. Cost and ease of construction are important but looks are not (within reason). I should add that this box is made in sections on wheels to enable access so weight is an issue.