There are several reinforcing ribs in the burglar-proof door body sandwich and filled with foaming agent, rock wool and other fillers. Rock wool is a material that can be soundproofed, but there are also some security doors that do not put rock wool inside. The soundproofing effect will be much worse, and it is a bit difficult to modify the security door. The best way is to install a wooden door.
Security Door Supplements:
First, the key factor of soundproofing of security doors lies in the thickness of steel plates. The thicker the steel plates, the better the sound insulation.
Second, the secondary factor in noise protection of the security door is the damping of the steel plate, that is, the less the vibration of the steel plate, the better the sound insulation.
Third, the most important factor in noise protection of the security door is the sound-absorbing material filled inside. High-density rock wool is the first choice, and the cost is low. It is good for low-middle absorption and has a certain damping effect. Polyurethane foam and honeycomb paper do not help the sound insulation.