How do I insulate space in loft to create music studio
Have a look at my answer on this question regarding acoustic foam. You will be able to cut down sound propagation significantly using it, by coating the walls and ceilings of your rooms with the foam.

If you have the capability, you could make a significant difference by mounting the rooms on rubber bushings.

This may be overkill for your purposes, but it is used for recording studios etc. as it dramatically reduces vibration through the walls and floors being transmitted.