Answer: the poor seal and the low mass of the door must be remedied.
You must first make sure that the peripheral seals of the door are tightly sealed. The door must be closed as tightly as possible. Consider getting elastic or metallic seals to fill the gaps around the door or even acoustic threshold bars to make the closure completely airtight. It is also possible to add mass to the leaf. The heavier it is, the more it will be insensitive to sound vibrations. There are very dense products that can stick to the leaf. Also think of panels of medium or plaster that can weigh down the door and therefore increase its sound insulation. For more global issues, whether for a home, a factory or a music studio, professional acoustics experts like Solutions Elastomères offer you specific acoustic foams and tailor-made insulation projects. Do not hesitate to consult themvideo id = "0" / Our practical decoration recovery videos