Normal domestic doors are too light and ill fitting to provide effective sound insulation. If more sound insulation is required, they can be replaced with plaster filled fire doors, fitted so as to be airtight when closed which will entail the fitting of a threshold. Good seals can be achieved using good quality draughtproofing. Mortice locks and open holes through the door should be avoided.
A double door entry system will be more effective at reducing noise breaking through. This entails two plaster filled fire doors fitted so one opens outwards and the other opens inwards. Both should be fitted so as to be sealed when closed as previously described.
In order to prevent leakage of sound around the edge of the door a number of seals may be used these are normally soft rubber strips fixed into recessed channels
Before installing sound insulation as described above, your room would have had a very poor insulation value which would no doubt, be very disturbing for your neighbours.
The newly insulated room will substantially reduce noise nuisance in other rooms but it must be appreciated that loud noise will still be heard, particularly low frequency sounds as emitted by drums.
Thin pressed steel up and over doors are impossible to insulate so should ideally be removed and bricked up or replaced with heavy, solid wood swing doors, fitted so they are sealed when closed. If this is not possible, assuming there is an alternative entrance, a timber stud partition should be built on the inside of the door, infilled with Acoustic Mineral Wool (AMW) and clad with two layers of 12mm plasterboard.
A double door entry system will be more effective at reducing noise breaking through. This entails two plaster filled fire doors fitted so one opens outwards and the other opens inwards. Both should be fitted so as to be sealed when closed as previously described.